Thursday, December 21, 2017

Breastfeeding Lowers the Risk for High Blood Pressure and Other Problems in Mid-Life

Photo credit: La Leche League
A new study indicates that breastfeeding can lower the risk for hypertension in middle-aged African-American women.

Interestingly, the study did not find much protection against EVER getting high blood pressure, but it did find a modest protective effect of breastfeeding on getting high blood pressure in your 40s. In other words, it had a temporary but important protective effect as women approached menopause, when high blood pressure often develops. In addition, the longer the duration of breastfeeding, the more protection there was.

This seems to echo other studies in other groups that have found similar protective effects against blood pressure issues in early middle age (the 40s) but not as much difference in older ages (after 65 or so).

It's disappointing that breastfeeding doesn't have the long-term, permanent effect everybody hoped for, but even so, this delay in development of high blood pressure is very important because the longer you have high blood pressure, the more complications like heart disease or kidney disease develop. Even just delaying it can reduce the cumulative disease burden on the body.

Breastfeeding can hopefully help people minimize their risk for these diseases. This is especially important for African-Americans, who are particularly susceptible to early onset of hypertension and cardiovascular issues.

More support  is needed in helping African-American women initiate and breastfeed long-term because it could make a critical difference in their health, as well as their babies' health. Here are some resources that might be helpful:

And here are some general breastfeeding resources:
Implications Beyond Hypertension 

Photo Credit: Center for Disease Control
Breastfeeding has important lifelong benefits beyond the obvious immediate benefits to the baby.

One of these is the delay of development of hypertension in the mother. Research also shows the breastfeeding, especially long-term breastfeeding, helps prevent or delay diabetes and heart problems, and lowers the incidence of cardiovascular mortality (see studies in References below).

Biologically speaking, women evolved to have children and then breastfeed them for extended periods of time. When women have children but don't breastfeed (or breastfeed only briefly), there is inadvertent metabolic fallout. As one study summarizes:
Researchers hypothesize that pregnancy and lactation are part of a continuum, with lactation meant to "reset" the adverse metabolic profile that develops as a part of normal pregnancy, and that when lactation does not occur, women maintain an elevated risk of cardio-metabolic diseases.
This is not to shame or scold women who don't or can't breastfeed long-term. Not every woman can breastfeed fully, some women's situations prevent breastfeeding for long, and of course it's always up to the woman to decide how she will feed her baby.

But from an evolutionary point of view, breastfeeding, especially long-term breastfeeding, keeps women healthier longer. 

We need to do everything we can to help support breastfeeding women, and especially breastfeeding women of color.


Breastfeeding and Hypertension

Am J Epidemiol. 2017 Oct 15;186(8):927-934. doi: 10.1093/aje/kwx163. Cumulative Lactation and Onset of Hypertension in African-American Women. Chetwynd EM, Stuebe AM, Rosenberg L, Troester M, Rowley D, Palmer JR. PMID: 28535171
Hypertension affects nearly 1 of 3 women and contributes to cardiovascular disease, the leading cause of death in the United States. Breastfeeding leads to metabolic changes that could reduce risks of hypertension. Hypertension disproportionately affects black women, but rates of breastfeeding among black women lag behind those in the general population. In the Black Women's Health Study (n = 59,001), we conducted a nested case-control analysis using unconditional logistic regression to estimate the association between breastfeeding and incident hypertension at ages 40-65 years using data collected from 1995 to 2011... Overall, there was little evidence of association between ever breastfeeding and incident hypertension (odds ratio = 0.97, 95% confidence interval: 0.92, 1.02). However, age modified the relationship (P = 0.02): Breastfeeding was associated with reduced risk of hypertension at ages 40-49 years (odds ratio = 0.92, 95% confidence interval: 0.85, 0.99) but not at older ages. In addition, risk of hypertension at ages 40-49 years decreased with increasing duration of breastfeeding (P for trend = 0.08). Our results suggest that long-duration breastfeeding may reduce the risk of incident hypertension in middle age. Addressing breastfeeding as a potential preventative health behavior is particularly compelling because it is required for only a discrete period of time.
Am J Obstet Gynecol. 2013 Jun;208(6):454.e1-7. doi: 10.1016/j.ajog.2013.02.014. Epub 2013 Feb 7. Association between parity and breastfeeding with maternal high blood pressure. Lupton SJ, Chiu CL, Lujic S, Hennessy A, Lind JM. PMID: 23395924
...Baseline data for 74,785 women were sourced from the 45 and Up Study, Australia. These women were 45 years of age or older, had an intact uterus, and had not been diagnosed with high blood pressure before pregnancy...The combination of parity and breastfeeding was associated with lower odds of having high blood pressure (adjusted OR, 0.89; 99% CI, 0.82-0.97; P < .001), compared with nulliparous women...Women who breastfed for longer than 6 months in their lifetime, or greater than 3 months per child, on average, had significantly lower odds of having high blood pressure when compared with parous women who never breastfed. The odds were lower with longer breastfeeding durations and were no longer significant in the majority of women over the age of 64 years....
Breastfeed Med. 2015 Apr;10(3):163-7. doi: 10.1089/bfm.2014.0116. Epub 2015 Mar 18. Breastfeeding and maternal hypertension and diabetes: a population-based cross-sectional study. Zhang BZ, Zhang HY, Liu HH, Li HJ, Wang JS. PMID: 25785993
...A cross-sectional study was conducted in four urban communities of Beijing, China, with 9,128 parous women 40-81 years of age who had had only one lifetime birth...After the analysis was adjusted for the potential confounders...the odd ratio (OR) of hypertension was 1.18 (95% confidence interval [CI], 1.05-1.32) for women who did not breastfeed, compared with women who did. In addition, the ORs for >0 to 6 months, >6 to 12 months, and >12 months of breastfeeding were 0.87 (95% CI, 0.76-0.99), 0.83 (95% CI, 0.68-1.00), and 0.79 (95% CI, 0.65-0.97), respectively, compared with women who did not breastfeed. With adjustment for age, WHR, working status, educational level, family history of diabetes, and postpartum BMI, women who did not breastfeed increased the risk of diabetes (OR=1.30; 95% CI, 1.11-1.53) compared with women who did. Moreover, women who breastfed for >0 to 6 months (OR=0.81; 95% CI, 0.67-0.98) and >6 to 12 months (OR=0.46; 95% CI, 0.26-0.84) had a lower risk of diabetes, compared with women who did not breastfeed. CONCLUSIONS: Chinese mothers who did not breastfeed were more likely to develop hypertension and diabetes in later life.
Am J Epidemiol. 2011 Nov 15;174(10):1147-58. doi: 10.1093/aje/kwr227. Epub 2011 Oct 12. Duration of lactation and incidence of maternal hypertension: a longitudinal cohort study. Stuebe AM, Schwarz EB, Grewen K, Rich-Edwards JW, Michels KB, Foster EM, Curhan G, Forman J. PMID: 21997568
Never or curtailed lactation has been associated with an increased risk for incident hypertension, but the effect of exclusive breastfeeding is unknown. The authors conducted an observational cohort study of 55,636 parous women in the US Nurses' Health Study II... In conclusion, never or curtailed lactation was associated with an increased risk of incident maternal hypertension, compared with the recommended ≥6 months of exclusive or ≥12 months of total lactation per child, in a large cohort of parous women.
Breastfeeding and Diabetes

Obstet Gynecol. 2016 Nov;128(5):1095-1104. Breastfeeding Initiation Associated With Reduced Incidence of Diabetes in Mothers and Offspring. Martens PJ, Shafer LA, Dean HJ, Sellers EA, Yamamoto J, Ludwig S, Heaman M, Phillips-Beck W, Prior HJ, Morris M, McGavock J, Dart AB, Shen GX. PMID: 27741196
This retrospective database study included 334,553 deliveries (1987-2011) in Manitoba with up to 24 years of follow-up for diabetes using population-based databases... RESULTS: Breastfeeding initiation was recorded in 83% of non-First Nations mothers and 56% of First Nations mothers (P<.001)... With 24 years of follow-up or less, breastfeeding initiation was associated with a 17% lower risk of youth-onset type 2 diabetes in offspring (HR 0.83, CI 0.69-0.99, P=.038)... CONCLUSION: Breastfeeding initiation is associated with a reduced risk of diabetes among women and their offspring in Manitoba. The results suggest that breastfeeding might be a potentially modifiable factor to reduce the risk of diabetes in both First Nations and non-First Nations women and children.
Diabetes Care. 2010 Jun;33(6):1239-41. doi: 10.2337/dc10-0347. Epub 2010 Mar 23. Parity, breastfeeding, and the subsequent risk of maternal type 2 diabetes. Liu B, Jorm L, Banks E. PMID: 20332359
...Using information on parity, breastfeeding, and diabetes collected from 52,731 women recruited into a cohort study, we estimated the risk of type 2 diabetes using multivariate logistic regression... Among parous women, there was a 14% (95% CI 10-18%, P < 0.001) reduced likelihood of diabetes per year of breastfeeding... CONCLUSIONS: Compared with nulliparous women, childbearing women who do not breastfeed have about a 50% increased risk of type 2 diabetes in later life. Breastfeeding substantially reduces this excess risk.
JAMA. 2005 Nov 23;294(20):2601-10. Duration of lactation and incidence of type 2 diabetes. Stuebe AM1, Rich-Edwards JW, Willett WC, Manson JE, Michels KB. PMID: 16304074
...Prospective observational cohort study of 83,585 parous women in the Nurses' Health Study (NHS) and retrospective observational cohort study of 73,418 parous women in the Nurses' Health Study II (NHS II)...RESULTS: ...Among parous women, increasing duration of lactation was associated with a reduced risk of type 2 diabetes. For each additional year of lactation, women with a birth in the prior 15 years had a decrease in the risk of diabetes of 15% (95% confidence interval, 1%-27%) among NHS participants and of 14% (95% confidence interval, 7%-21%) among NHS II participants, controlling for current body mass index and other relevant risk factors for type 2 diabetes. CONCLUSIONS: Longer duration of breastfeeding was associated with reduced incidence of type 2 diabetes in 2 large US cohorts of women....
Diabetologia. 2008 Feb;51(2):258-66. Epub 2007 Nov 27. Duration of breast-feeding and the incidence of type 2 diabetes mellitus in the Shanghai Women's Health Study. Villegas R1, Gao YT, Yang G, Li HL, Elasy T, Zheng W, Shu XO. PMID: 18040660
...This was a prospective study of 62,095 middle-aged parous women in Shanghai, China, who had no prior history of type 2 diabetes mellitus, cancer or cardiovascular disease at study recruitment... RESULTS: Women who had breastfed their children tended to have a lower risk of diabetes mellitus than those who had never breastfed [relative risk (RR)=0.88; 95% CI, 0.76-1.02; p=0.08]. Increasing duration of breast-feeding was associated with a reduced risk of type 2 diabetes mellitus. The fully adjusted RRs for lifetime breast-feeding duration were 1.00, 0.88, 0.89, 0.88, 0.75 and 0.68 (p trend=0.01) for 0, >0 to 0.99, >0.99 to 1.99, >1.99 to 2.99, >2.99 to 3.99 and >or=4 years in analyses adjusted for age, daily energy intake, BMI, WHR, smoking, alcohol intake, physical activity, occupation, income level, education level, number of live births and presence of hypertension at baselines....
Breastfeeding and Cardiovascular Health/Mortality

Annu Rev Nutr. 2016 Jul 17;36:627-45. doi: 10.1146/annurev-nutr-071715-051213. Epub 2016 May 4. Lactation and Maternal Cardio-Metabolic Health. Perrine CG, Nelson JM, Corbelli J, Scanlon KS. PMID: 27146017
Researchers hypothesize that pregnancy and lactation are part of a continuum, with lactation meant to "reset" the adverse metabolic profile that develops as a part of normal pregnancy, and that when lactation does not occur, women maintain an elevated risk of cardio-metabolic diseases. Several large prospective and retrospective studies, mostly from the United States and other industrialized countries, have examined the associations between lactation and cardio-metabolic outcomes. Less evidence exists regarding an association of lactation with maternal postpartum weight status and dyslipidemia, whereas more evidence exists for an association with diabetes, hypertension, and subclinical and clinical cardiovascular disease.
Am J Obstet Gynecol. 2009 Feb;200(2):138.e1-8. doi: 10.1016/j.ajog.2008.10.001. Epub 2008 Dec 25. Duration of lactation and incidence of myocardial infarction in middle to late adulthood. Stuebe AM, Michels KB, Willett WC, Manson JE, Rexrode K, Rich-Edwards JW. PMID: 19110223
We assessed the relation between duration of lactation and maternal incident myocardial infarction. STUDY DESIGN: This was a prospective cohort study of 89,326 parous women in the Nurses' Health Study. RESULTS:... Compared with parous women who had never breastfed, women who had breastfed for a lifetime total of 2 years or longer had 37% lower risk of coronary heart disease (95% confidence interval, 23-49%; P for trend < .001), adjusting for age, parity, and stillbirth history. With additional adjustment for early-adult adiposity, parental history, and lifestyle factors, women who had breastfed for a lifetime total of 2 years or longer had a 23% lower risk of coronary heart disease (95% confidence interval, 6-38%; P for trend = .02) than women who had never breastfed. CONCLUSION: In a large, prospective cohort, long duration of lactation was associated with a reduced risk of coronary heart disease.
BMC Public Health. 2013 Nov 13;13:1070. doi: 10.1186/1471-2458-13-1070. A prospective population-based cohort study of lactation and cardiovascular disease mortality: the HUNT study. Natland Fagerhaug T, Forsmo S, Jacobsen GW, Midthjell K, Andersen LF, Ivar Lund Nilsen T. PMID: 24219620
...In a Norwegian population-based prospective cohort study, we studied the association of lifetime duration of lactation with cardiovascular mortality in 21,889 women aged 30 to 85 years who attended the second Nord-Trøndelag Health Survey (HUNT2) in 1995-1997. The cohort was followed for mortality through 2010 by a linkage with the Cause of Death Registry...RESULTS:...Parous women younger than 65 years who had never lactated had a higher cardiovascular mortality than the reference group of women who had lactated 24 months or more (HR 2.77, 95% confidence interval [CI]: 1.28, 5.99)...CONCLUSIONS: Excess cardiovascular mortality rates were observed among parous women younger than 65 years who had never lactated. These findings support the hypothesis that lactation may have long-term influences on maternal cardiovascular health.

Sunday, December 10, 2017

Preventing Cesarean Complications in High BMI Women

In our last post, we discussed the best evidence-based practices for lessening the risk for infections and other wound complications after cesarean in women of all sizes. This is vital because 1 in 3 women in the United States has a cesarean these days, and many will have only cesareans because of lack of support for Vaginal Birth After Cesarean (VBAC). That's a lot of cesareans and a lot of chances for complications to happen.

However, if there are a lot of cesareans in women in general, there are even more in high BMI women, raising the potential for post-cesarean complications even further. 

The rate of cesareans in "obese" women is astronomically high, with rates in many studies hovering between 50-60% in high BMI women, and reaching as high as 70-80% at times. This is recipe for disaster because surgery is more risky in general in high BMI women and they have more wound complications afterwards.

Wound complications rise as BMI rises
Graph from Conner 2014
Research shows the risk for infection after cesarean in obese women is higher, and that infection risk rises as BMI increases. Surgical Site Infections (SSIs) are a real concern in very high BMI patients.

This is because fat layers have less vascularization and poorer oxygenation, making the healing process more difficult. Women of size also tend to have a higher risk for collections of fluid or blood in the wound (seromas and hematomas), which predispose to the wound coming apart and having trouble healing. Furthermore, the risk for blood clots after cesareans is increased in high BMI women as well, and blood clots can be deadly. So the implications of a high cesarean rate in women of size are very important.

The best way to lower cesarean morbidity in obese women is to lower the overall rate of unnecessary cesareans in this group. However, when cesareans are necessary, there are things that caregivers can do to decrease the risk for complications. These include:
  • Transverse incisions instead of vertical incisions 
  • Sutures instead of staples 
  • Increased or weight-based dosing of antibiotics 
  • Extended spectrum or extended regimen of antibiotics 
  • Thromboprophylaxis (blood clot prevention)
  • Closure of the subcutaneous space 
  • Avoidance of surgical drains 
  • Negative pressure wound therapy (possibly)
Transverse (Side-to-Side) Incision

Many providers have erroneously been taught that a vertical (up-and-down) incision will be safer and less prone to infection than a transverse (side-to-side) incision in obese women, especially as BMI goes up. They were taught that an overhanging belly (panniculus) would predispose to infection because of the potentially hot, moist environment under it.

For years this was an unquestioned belief, until a 2005 study found that there was TWELVE TIMES the risk for wound complications with a vertical incision compared to a transverse one in obese women.

A number of studies since then have also found increased wound complications and blood loss in vertical incisions in obese women and equivalent or better outcomes with transverse incisions.

Some doctors like to cite a 2014 study that supposedly found better results with a vertical incision. However, a further scrutiny of the data found that the researchers used the wrong variable in their analysis. When re-analyzed correctly, they found that a transverse incision was indeed superior. A retraction of the original study was made, but many doctors are unaware of it.

Some doctors use transverse incisions on women with moderate obesity but feel that vertical incisions are necessary on women with very high BMIs. However, one study on "super obese" women (BMI 50+) concluded that transverse incisions were preferable even in this group for many reasons:
Transverse abdominal incisions are less painful and allow for earlier mobilization and decreased pulmonary complications. Furthermore, vertical abdominal incisions were associated with vertical hysterotomy [uterine incisions] in our study, usually a result of inadequate access to the lower uterine segment. When the incision extends into the contractile portion of the uterus, a vertical hysterotomy has a profound impact on future pregnancy. Therefore, it is important to incorporate practices, like transverse abdominal incisions, that facilitate low uterine incisions.
At this time, most OBs have switched to transverse incisions in obese women, even very obese women. Although vertical incisions are sometimes indicated in rare cases or in true emergencies, it is usually not necessary to use a vertical incision even in very obese women. Low transverse incisions have been used successfully even in women of 400-500 pounds without poor outcomes. And higher transverse incisions (Joel-Cohen incisions done slightly higher, or transverse incisions near the umbilical in rare cases) are also an option if necessary.

However, some doctors stubbornly cling to a "vertical is better" policy, especially as BMI increases. Research shows that vertical/classical incisions are still more common in high BMI women than those with an average BMI.

Although most OBs today use the transverse incision on women of size, up to 20% prefer a vertical incision in women with a BMI over 40, despite its strong association with more wound problems. Using mostly transverse incisions is one obvious way to improve outcomes in high BMI women but one which some OBs are stubbornly slow to adopt.
Sutures Instead of Staples

Most OBs still use staples to close the skin incision after a cesarean. The advantage is that staples are completed more quickly, so the woman is not exposed as long to outside germs, which in theory may decrease the risk for infection. Staples are also relatively easy to apply; much easier than doing sutures.

Staples are used even more commonly in high BMI women. One large hospital in a major urban center recently documented that 63% of obese women in their institution received staples, while only 32.5% received subcuticular sutures.

If staples are used in obese women, some research indicates that it may be advantageous to leave them in slightly longer before removal. However, while there was a distinct trend towards less complications in the delayed removal group, the difference did not rise to statistical significance. Optimal timing of the removal of staples in obese women is a question still to be answered.

But the best choice for skin closure in women of size is probably subcutaneous sutures.

meta-analysis in women of all sizes found that sutures lowered the rate of wound complications considerably, even when obesity was controlled for. One hospital in Alabama found that staples was associated with more than five times the risk for wound disruption. Furthermore, a hospital in San Diego was able to lower its wound complication rate from 10.1% to 4.5% by making an institutional switch from staples to sutures.

Sutures do take longer to do, but the difference is only 5-10 minutes. Taking longer might raise the risk for infection slightly, but using sutures lowers the risk for infection far more than a slightly longer surgery raises it. This is a very reasonable trade-off.

Similarly, new research confirms that using sutures instead of staples lowers the risk for wound complications in obese women. One recent study found a 22% rate of wound complications in obese women who were closed with staples, versus a 9.7% rate in those closed with sutures. That's a striking difference.

Despite this, doctors are LESS LIKELY to use sutures as BMI goes up. It is not clear why this is true, but probably many OBs don't want to take the time and effort to do subcuticular sutures on very fat women (which is harder), and they don't feel the same need to make the scar look seamless and "pretty" for very large women.

But it bears repeating that to improve outcomes in high-BMI women with cesareans, sutures should be used more often, even as BMI increases. It should not be about what saves the surgeon the most time, the technical difficulty of suturing adipose tissue, or about whether a larger woman "needs" to have a beautiful scar; it should be about what decreases the risk for wound complications, and sutures clearly do that best.

Staples vs. sutures is one area that needs a major change of practice, both among women of average size and among high BMI women. Yet many surgeons greatly resist changing this practice.

Weight-Based Dosing of Antibiotics

We have written before about the importance of weight-based dosing for certain types of antibiotics. Not every type of antibiotic needs weight-based dosing, but some do. It all depends on their mechanism of action.

The class of antibiotics called cephalosporins is one of the most commonly used antibiotics before a cesarean and many other surgical procedures. It is chosen because it is generally well-tolerated, is effective against skin-borne pathogens, and has a low incidence of allergic reactions. Cefazolin is the most commonly used cephalosporin in cesareans.

The right dosage of antibiotics is very important. Too high a dose and serious side effects like severe diarrhea or organ damage can occur. Most of the good bacteria in your gut can be obliterated, leaving the bad antibiotic-resistant bacteria like C. difficile to take over. But too low a dose and the infection may not be completely wiped out, enabling the bad bacteria to develop resistance, causing a resurgent infection that does not respond to antibiotics. This can cause a prolonged recovery or even death. So finding the right dose is a balance between too much and too little.

Most of the research on dosage of antibiotics has been done on people of average size but applied to people of all sizes. Obese patients were frequently excluded from dosage studies. Only recently have researchers begun asking what the best dosage is for high BMI people, and they still have only limited data to guide them.

Historically, underdosing high BMI people has been a serious problem. Doctors assume that most obese people have impaired liver and kidney function, so they erred on the side of conservative dosing in order to minimize possible side effects and organ damage. But in doing so, they have been exposing obese patients to higher risks of infection and wound issues.

Some pharmacological research is now being done to determine optimal dosing by body weight, but guidelines are sparse and have major gaps in knowledge. Even when optimal dosing guidelines do exist, doctors often do not follow them.

The standard dosage used to be 1g of cefazolin before cesarean for all sizes of women, but now 2g is recommended to improve outcomes in obese women.

Some guidelines and researchers have suggested that very high BMI patients having various types of surgery might need a 3g dose (or more) instead in order to reach the minimum inhibitory concentrations needed to prevent infection.

Research on whether 3g does improve outcomes has been mixed. In non-cesarean surgeries, outcomes do not seem improved by the higher initial dose. However, in cesareans in class III and IV obesity (BMI over 40 and 50) there is some research to suggest improved outcomes, but other research disagrees or is inconclusive.
At this time, most moderately obese women are given 2g of cefazolin and generally do well. Beyond that, more research is needed.

Best guess is that it is probably not necessary to increase dosages beyond 2g in women with BMIs between 30 and 40. However, we need additional research, stratified by BMI, on the optimal dosage for women in class III (BMI 40 or more) and super obesity (BMI 50 or more). This research is urgently needed, but until we have it, it seems sensible to err on the side of 3g when BMI nears or exceeds 50, or to consider the use of additional antibiotics (see below).

Extended Spectrum or Extended Regimen Antibiotics

It may be that improving post-surgical outcomes in high BMI people is about both how much antibiotics they receive initially and whether they receive additional antibiotic agents during or after the surgery. Weight-based dosing and extended antibiotic regimens is something size-acceptance activists have been pushing for for years, but only now is the medical community really starting to take it seriously.

Old standards called for antibiotics to be discontinued after surgery or within 24 hours. New research has shown that a combination of antibiotics and/or the addition of more antibiotics during surgery or post-operatively lowers the risk for infections and other complications in women of all sizes, and particularly in high BMI women.

For example, a multi-center large study on women of all sizes showed that cefazolin plus azithromycin was more effective in reducing post-operative complications. Serious infections were cut in HALF.

It would be interesting for this study to be duplicated in a group of diverse obese women, stratified by BMI. That would tell us whether the addition of azithromycin would be especially helpful in larger women, and at what BMI cutoffs.

One important recent study of obese women having cesareans found that an IV cephalosporin before surgery followed by an oral dose of both a cephalosporin and metronidazole 3x/day for 2 days afterwards decreased infections quite significantly. SSIs were diagnosed in only 6.4% receiving post-operative oral antibiotics, versus in 15.4% of the women receiving a placebo after surgery. That's an impressive decrease for just 2 more days of antibiotics.

An editorial accompanying this study called for more research on whether special subgroups might particularly benefit from post-operative antibiotics. They noted that in the group of obese women whose waters had been broken during labor, the infection rate was strikingly lower in those who received post-op antibiotics vs. those who received a placebo (9.5% vs. 30.2%). The difference was only minimal in the group whose waters were still intact (5% vs. 8.7%). So it may be that we don't need to give all obese women routine post-op antibiotics, but that its use should be prioritized to obese women with extra risk factors for infection.

Unfortunately, there is only very limited research on cesarean antibiotic regimens in obese women, so many protocols are extrapolated from bariatric or gynecologic surgeries. This potentially limits their applicability to obstetric situations but at least offers some guidance in the absence of other data.

During bariatric surgery, for example, one study found that an initial pre-operative 2g dose of cefazolin followed by an additional 1g of cefazolin given by continuous IV dosage during the surgery resulted in better outcomes than other combinations of various antibiotics.

In one gynecological study of obese women receiving a hysterectomy and panniculectomy (removal of extra belly fat and skin, which has a high risk for infection), a regimen of 2g of cefazolin at surgery and then oral ciproflaxin post-operatively resulted in far fewer SSIs (5.9% vs. 27.9%).

So bariatric and gynecologic data and preliminary research in obstetric populations suggest that additional antibiotics after surgery may be helpful in high BMI women, especially those with additional risk factors. But it's very frustrating that more work has not been done on this in high BMI women, given how many cesareans are egregiously being done in this group. How many problems could have been prevented if this research had already been done so providers knew the best practice?

Even the obstetric studies we do have tend to be sub-par. Most have been too small to be really meaningful. Some have focused only on concentrations of cefazolin in the blood at various times in surgery, rather than also including outcome data (how many women developed infections afterwards in the different dosing groups). Concentrations in the blood are an important potential indicator of problems, but what really counts is how this all translates into actual outcomes.

We need more data specifically on antibiotic dosage for CESAREANS in obese women, stratified by BMI, emphasizing actual outcomes, rather than doctors extrapolating dosages from other types of surgery or from blood and tissue concentrations. 

Until we have the data we need to confirm best practices, expert advice and common sense seem to suggest using at least 2g dosages in women above a BMI of 30-35, and to consider using 3g for women with a BMI over 50 or extra risk factors for infections like broken waters, diabetes, heavy blood loss, etc. Alternatively, adding extra antibiotics (either during surgery or post-operatively) should be considered in these women. As one guide summarizes:
Extended-spectrum antibiotic prophylaxis, with an agent such as azithromycin, may be beneficial in patients at higher risk of postcesarean infectious morbidity, such as those who are obese or diabetic.
Thromboprophylaxis Questions

Obesity increases the risk for blood clots in general, and so does pregnancy. Having cesarean surgery further increases the risk for blood clots. Therefore, obese pregnant women subjected to a cesarean are at particular risk for blood clots. Preventing this is an important part of improving cesarean outcomes in women of size.

Although the absolute risk of getting a blood clot  in this group is relatively small, the potential for great harm or death is very high if it does occur. Blood clots can travel to the lungs (pulmonary embolism), to the brain (stroke), or to the heart (heart attack), and can be fatal.

Sometimes caregivers don't take the possibility of blood clots seriously enough in obese women; there has been more than one story of an obese woman complaining of shortness of breath after a cesarean, only to have it shrugged off by a doctor as being caused by being "overweight and out of shape." Missing a pulmonary embolism can be deadly, so caregivers must take symptoms seriously and not blame obesity alone for symptoms.

On the other hand, some in the obstetric community overreact to the possibility of blood clots in high BMI women and prescribe blood thinners for every high BMI woman, even when there are no other risk factors and she gives birth vaginally.

Too little blood thinner when needed increases the risk for deadly blood clots. Too much blood thinner can result in hemorrhage and wound complications. Finding the right balance is critical.

The first question about thromboprophylaxis in obese women is whether these drugs should be routinely administered to all obese women to prevent blood clots, or used only when additional risk factors necessitate them.

At this point, there is little research on the topic. Standard protocol for preventing blood clots is getting the patient walking as soon as possible after surgery, and using pneumatic mechanical devices or compression stockings to stimulate blood flow while in bed. These approaches work very well to prevent blood clots in most cesarean mothers, including obese women, without blood thinners. The standard of care in the U.S. is to use blood thinners only when indicated by extra risk factors.

On the other hand, the NICE guidelines in the U.K. suggest using blood thinners prophylactically for 7-10 days with ALL obese patients with a BMI of 40 or more, regardless of how they gave birth. However, this recommendation was developed by the Royal College of Obstetricians and Gynaecologists based on "consensus," not on data that shows improved outcome with routine thromboprophylaxis in all obese women. We need recommendations based on actual data, not guesses and fears.

Some research suggests increased wound complications in obese women who receive thromboprophylaxis. Further research is needed to determine the benefits and harms of routine use of thromboprophylaxis in obese cesarean patients before such a policy is implemented widely.

It's doubtful that thromboprophylactic drugs need to be used routinely in every high-BMI woman. However, routine blood thinners probably are a wise precaution in those who are particularly at risk for blood clots, like smokers, those with a family history suggestive of clotting disorders, those who cannot move around freely, and perhaps in super-obese patients.

Another important question is thromboprophylaxis dosage. If weight-based dosing of antibiotics is important for improving outcomes in women of size, what about weight-based dosing for blood thinners?

As with antibiotics, most thromboprophylaxis research has not included adequate numbers of obese subjects so optimal dosing remains based on guesswork. The type of blood thinner being used matters; direct oral anticoagulants like Eliquis (apixoban) do not need weight-based dosing, whereas unfractionated heparin and low molecular weight heparin (the drugs used in pregnancy) do benefit from weight-based dosing.

The most commonly used blood thinner after cesareans is a low molecular weight heparin like Lovenox (enoxaparin sodium). Recent research shows that weight-based dosing of products like Lovenox is helpful in preventing blood clots. One study found that 88% of post-cesarean obese women achieved the minimum concentration needed when weight-based dosing was used, but only 14% achieved it when standard dosing was used.

Another study found that weight-based dosing was superior to BMI-category dosing after a cesarean. In other words, dosing by actual weight had better outcomes than generalizing one dosage for all women between a BMI of 40-50, for example. 86% of patients with weight-based dosing had optimal anti-clotting concentrations, compared with only 26% on the BMI-stratified dosing.

Further research on when and how to use thromboprophylactics in high BMI women is needed, but if thromboprophylactics are given, they should be dosed in a way that will be effective for the patient's size, and that means weight-based dosing.

Closure of Subcutaneous Space

When there is a substantial fat layer, there is an increased risk for surgical wounds to re-open. Adipose tissue tends to be poorly vascularized, and this relative lack of blood flow means there is less oxygenation. In addition, leaving a gap in this adipose tissue may predispose the area to seromas (collections of fluid in the wound), which may inhibit wound healing.

So years ago some surgeons began loosely closing the subcutaneous space in an extra layer in the hopes of improving outcomes. What they found was that closing the subcutaneous space didn't make much difference if the adipose layer was small, but it made a very significant difference if the adipose layer was greater than 2 cm.

In one study, closing the subcutaneous layer when it exceeded 2 cm cut the rate of wound complications in obese women by a third.

Experts agree that closing the subcutaneous space lessens the risk for infections, seromas, and wound dehiscence in women of size. It should be standard of care to improve outcomes in high-BMI women, but while it is used by many surgeons, it is not yet used universally.

Avoidance of Surgical Drains

The use of surgical drains (like a Jackson-Pratt drain) to siphon off excess fluid accumulating in the cesarean wound is controversial.

Drains were thought to be necessary to prevent seromas, which then might raise the risk for infection and the wound coming open.

On the other hand, drains leave open a path for infection into the body and may increase the risk for a seroma, not decrease it. Although an occasional study has found drains helpful, more studies have found drains to be of no benefit or even to be harmful.

At this point, most experts recommend against the routine use of surgical drains after a cesarean, even in very obese women.

Negative Pressure Wound Therapy

Another technique that is being investigated to reduce wound complications after cesareans is Negative Pressure Wound Therapy (NPWT). A "Wound Vac" is placed over the incision and then sealed. The negative pressure is thought to help the wound heal faster and cleaner, although not all studies have found it helpful.

Still, some studies have proposed routine use of NPWT in patients at higher risk for infection and wound complications after surgery, which many would interpret to include obese women after cesarean. Whether this is a good idea or not remains to be seen. Certainly some people with established infections are clearly helped by NPWT, so it should absolutely remain a tool in the toolkit for when infections occur. But whether it should be routinely used with all obese patients as a potential prevention measure needs more study.

One recent small study found a trend towards less wound complications and decreased use of pain medications in the negative pressure wound therapy group, and another small study found fewer infections.  However, a meta-analysis of several studies found no real benefit to using negative pressure wound therapy prophylactically in obese women.

More data is needed on its routine use in obese women having cesareans before it can be recommended. However, it is another option that women of size can discuss with their provider for treatment if they do experience a wound infection. Other options that may help heal wound infections include silver-impregnated wound dressings and perhaps medical honey.


As we discussed in the first post of this series, research is clear that there are many things providers can do to lower a woman's risk for complications after a cesarean, including:
  • Antibiotics administered before skin incision 
  • Adding an additional antibiotic to the standard cephalosporin 
  • Using chlorhexidine-alcohol (Hibiclens) for disinfecting the skin instead of iodine 
  • Using clippers on body hair instead of shaving the area 
  • Removing the placenta through gentle traction instead of by manual removal 
  • Closing the wound with sutures instead of with staples 
Some of these interventions have been adopted quickly and gladly by the obstetric community, while others are still struggling to find widespread acceptance. One recent review of over 1,000 patients found that only one-third of cesarean mothers received all four of the evidence-based bundle recommendations in that study to reduce wound complications. These are extremely basic precautions, and yet two-thirds of women receiving cesareans did not get them. Obviously, there is huge room for improvement here.

Precautions Specific for High BMI Women

There is even more room for improvement in the treatment of high BMI women. We know that these women are more at risk for infections and wound complications after cesarean compared to average-sized women, yet they often do not receive interventions that would lessen their risk.

Here is a best-practice summary of the things that clinicians can do to decrease the risk for infection and wound complications after a cesarean in obese women and an evaluation of how well these practices have been adopted by the obstetric community:
  • Transverse incision instead of a vertical incision - Transverse incisions greatly decrease wound dehiscence and blood loss in obese women, yet doctors still use vertical incisions too often in obese women, especially as BMI goes up. While most OBs use transverse incisions in larger women, too many are still using vertical incisions; this practice must change
  • Sutures instead of staples - Skin closure with sutures decreases the rate of Surgical Site Infections in both average-sized and high BMI women, yet research shows that surgeons are less likely to use sutures with obese women. Hospitals must start promoting sutures for skin closures in all women, but especially in women of size
  • Weight-based dosing of antibiotics - Weight-based dosing of 2g (and possibly 3g for very high BMI women) of a cephalosporin like cefazolin decreases infection rates in obese women. More outcome-based research, stratified by BMI, is needed to determine optimal dosages
  • Extended spectrum/regimen antibiotics  - New research suggests that standard antibiotics plus an extended spectrum antibiotic or post-operative antibiotics improves outcomes in high BMI women, but this is not routine practice yet. More research specific to high BMI women and cesareans is needed to determine the most optimal antibiotic regimens
  • Weight-based dosing of thromboprophylaxis - Mechanical means of lessening the risk for blood clots (compression stockings, pneumatic pumps, early ambulation) should be automatically used with obese women post-operatively. Routine use blood-thinning drugs in all high BMI women needs more research before being implemented. If there are multiple strong risk factors for blood clots, then thromboprophylactic drugs should be strongly considered, using weight-based (not fixed) dosing
  • Closure of the subcutaneous space - Research has been clear for a long time that suturing a subcutaneous tissue depth of 2 cm or more improves outcomes. While many OBs do this, not all do. Closure of the subcutaneous space should be automatic by now for all obese women
  • Avoidance of surgical drains - Current consensus is that surgical drains are not helpful or necessary in obese women and may well worsen outcome. Most OBs no longer use surgical drains in obese women, but a few still do. This practice should stop
  • Negative Pressure Wound Therapy - Research is mixed on NPWT right now. Some research shows benefit, but a meta-analysis of trials in obese women shows no difference in outcomes. More research is needed, but NPWT in obese women is probably only justified in those with infection, or possibly in those at highest risk of infection due to multiple strong risk factors 
Clearly, there are things that clinicians can do to improve outcome among high BMI women who have a cesarean. Sadly, research shows that some of the above steps are actually LESS likely to be used with high-BMI women, especially those in the upper echelons of BMI.

Graph from Connor 2014
Look at the graph. The blue bars show the rate of midline vertical incisions increases greatly as BMI goes up. This may be one reason why the blood loss rates (pink bars) are higher as BMI increases, since vertical incisions result in more blood loss. And the greater the blood loss, the more risk for infection.

The green bars show that the rate of suture closure is quite a bit lower in the obese groups. There is a small increase of suture use in the BMI >50 group compared to the BMI 40-49 group, but the difference is marginal. Taken as a whole, the suture rate is much lower in all of the obese groups compared to the BMI <30 group, despite the fact that we know that sutures would lower the risk for infection in this group.

In other words, the very things that increase wound complications the most (use of staples and use of vertical incisions) is actually increased in obese women! This is unconscionable, especially when we know that obesity is such a strong risk factor for SSIs and wound complications after a cesarean.

It's also important to point out that in the 2017 review referenced above, when all four best practices were used (antibiotics before skin incision, chlorhexidine-alcohol skin prep, closure of subcutaneous layer if ≥2 cm of depth, and subcuticular skin closure with suture), strong risk factors like diabetes, smoking, and obesity were no longer associated with wound complications.

In other words, while obesity is a risk factor for wound problems and infections after cesareans, with evidence-based care, this risk can be greatly decreased.

The difficulty is in getting care providers to routinely follow best practices with high BMI women. Much progress is needed in this area.
The Best Prevention is Fewer Cesareans

When cesareans do occur in high BMI women, it is important to minimize the risk for infection and wound complications. For a long time, practice was based mostly on guesswork rather than on real data. Now we have more data to guide best-practice guidelines, though we still need more.

However, the best way to prevent wound complications and infections is by doing fewer cesareans in this group. 

The cesarean rate is outrageously high in obese women. There are many studies documenting a high c-section rate in obese women, and the cesarean rate has increased more in "morbidly obese" women than in other BMI groups over time.

VBAC is often strongly discouraged in heavier women, leading to a high rate of repeat cesareans. Yet multiple cumulative cesareans carries a particularly high morbidity rate for high BMI women compared to other women.

But care providers are not powerless to lower the c-section rate. Many studies have shown that cesarean rates can be lowered safely when attention is focused on the problem.

Yet not one study has been done to see how to lower the cesarean rate in obese women.

There are studies that speculate about ways to lower the c-section rate in women of size, but I have yet to see a randomized controlled study that tested specific protocols and how they affect outcomes. Without direct evidence, all we can do is speculate about actions likely to lower the cesarean rate in this group.

The most obvious way to improve the c-section rate in obese women would be to lower the rate of planned elective cesareans in this group. Many care providers routinely schedule non-labor cesareans for women with a high BMI, even though research shows this does not improve outcome. In one recent study, one-third of very obese women had primary cesareans without labor. Another recent study found that 42% of women with a BMI >50 were scheduled for planned non-labor cesareans. If some of these women then develop serious wound complications (not to mention the downstream complications of placental issues in future pregnancies), that's a LOT of morbidity resulting from cesareans that are questionable in the first place.

The cesarean rate in women of size who labor could probably be considerably reduced with more physiologic labor management. Many care providers have been taught that a high cesarean rate in labor is inevitable in very fat women, yet rates are actually highly variable in obese women. This suggests that there is room for change.

For example, one study of "super obese" (BMI 50+) women from the U.K. showed HALF the cesarean rate compared to a similar group in Kentucky and other groups in Australia and Canada. The U.K. rate was 30%, vs. the 50-60% cesarean rate of super obese women in other areas. This shows that the cesarean rate in labor could be far less in high BMI women, and is potentially modifiable.

Most very obese women rarely see midwives and this may also be part of why they have high cesarean rates, since hospitals with a high rate of births attended by midwives tend to have lower cesarean rates. Research shows that midwives can safely attend obese birthing women.

Obese women are induced at very high rates, and this may be a strong part of the cesarean rate in this group as well. In addition, obese women are submitted to high rates of interventions during labor compared to other women. More patience during labor, especially in the early phase up to 6 cm of dilation, may be needed in the labors of obese women. Research suggests the cesarean rate in obese women could be lowered considerably with better management and more patience.

Women who have had a cesarean should usually be encouraged to VBAC if they wish it. Even though VBAC rates are modestly lower in obese women and VBAC prediction models are often used to counsel high BMI women away from VBAC, recent research shows that many obese women CAN have a VBAC with good support.

Actions taken in labor may influence the rate of wound complications if a cesarean does occur. Caregivers often push obese women have early placement of epidurals and rupture of membranes for internal fetal monitors, but these may be associated with higher risk for infection and wound complications if the mother ends up with a cesarean. In addition, lowering the number of vaginal exams in labor and keeping the waters intact as long as possible during labor may help lower the risk for infection if a cesarean does become necessary.

There are many possibilities for trying to lower the cesarean rate in obese women, but at this point, no one is even seriously studying how to do so. It is time for that to change.

If doctors truly want to lower the high rate of cesarean wound complications in obese women, the most effective way to do so is to lower the number of cesareans done in this group. Then if a cesarean does become necessary, the hospital should ensure that physicians use evidence-based protocols based on research into women of size. 


General References
Obesity and Avoiding Cesarean Wound Complications

Am J Obstet Gynecol. 2017 Jun 8. pii: S0002-9378(17)30734-2. doi: 10.1016/j.ajog.2017.05.070. [Epub ahead of print] Impact of evidence-based interventions on wound complications after cesarean delivery. Temming LA, Raghuraman N, Carter EB, Stout MJ, Rampersad RM, Macones GA, Cahill AG, Tuuli MG. PMID: 28601567
...Risk of wound complications in women who received all 4 evidence-based measures (prophylactic antibiotics within 60 minutes of cesarean delivery and before skin incision, chlorhexidine-alcohol for skin antisepsis with 3 minutes of drying time before incision, closure of subcutaneous layer if ≥2 cm of depth, and subcuticular skin closure with suture) were compared with those women who did not...RESULTS: Of 1082 patients with follow-up data, 349 (32.3%) received all the evidence-based measures, and 733 (67.7%) did not. The risk of wound complications was significantly lower in patients who received all the evidence-based measures compared with those who did not (20.3% vs 28.1%; adjusted relative risk, 0.75; 95% confidence interval, 0.58-0.95)...Other risk factors, which include obesity, smoking, diabetes mellitus, chorioamnionitis, surgical experience, and skin incision type, were not significant among patients who received all of the 4 evidence-based measures....
N Am J Med Sci. 2012 Jan;4(1):13-8. doi: 10.4103/1947-2714.92895. Cesarean section in morbidly obese parturients: practical implications and complications. Machado LS. PMID: 22393542 Full free text can be found here.
...A Medline search was conducted to review the recent relevant articles in english literature on cesarean section in morbidly obese women. The types of incisions and techniques used during cesarean delivery, intra-operative and postpartum complications, anesthetic and logistical issues, maternal morbidity and mortality were reviewed...Low transverse skin incisions and transverse uterine incisions are definitely superior and must be the first option. Closure of the subcutaneous layer is recommended, but the placement of subcutaneous drains remains controversial. Thromboprophylaxis adjusted to body weight and prophylactic antibiotics help in reducing postpartum morbidity....
Best Pract Res Clin Obstet Gynaecol. 2015 Apr;29(3):406-14. doi: 10.1016/j.bpobgyn.2014.08.009. Epub 2014 Oct 16. Obesity and the challenges of caesarean delivery: prevention and management of wound complications. Ayres-de-Campos D. PMID: 25457856
Caesarean section in obese patients is associated with an increased risk of surgical wound complications, including haematoma, seroma, abscess and dehiscence... Appropriate dose of prophylactic antibiotics, closure of the subcutaneous tissue, and avoidance of subcutaneous drains reduce the incidence of wound complications associated with caesarean section in obese patients. For treatment of superficial wound infection associated with dehiscence, there are data from general surgery patients to suggest that the use of vacuum-assisted devices leads to faster healing and that surgical reclosure is preferable to healing by secondary intention, when there are no signs of ongoing infection. There is a need for stronger evidence regarding the prevention and management of wound complications for caesarean section in obese women.
Surg Infect (Larchmt). 2015 Apr;16(2):174-7. doi: 10.1089/sur.2014.145. Epub 2015 Mar 31. A journey to zero: reduction of post-operative cesarean surgical site infections over a five-year period. Hickson E, Harris J, Brett D. PMID: 25826622  Full free text found here.
...A risk-based approach to incision management was developed and implemented for all cesarean deliveries at our institution. A number of incremental interventions for low-risk and high-risk patients including pre-operative skin preparations, standardized pre- and post-operative protocols, post-operative nanocrystalline silver anti-microbial barrier dressings, and incisional negative pressure wound therapy (NPWT) were implemented sequentially over a 5-y period. A systematic clinical chart review of 4,942 patients spanning all cesarean deliveries between 2007-2012 was performed to determine what effects the interventions had on the rate of SSI for cesarean deliveries. RESULTS: The percentage of SSI was reduced from 2.13% (2007) to 0.10% (2012) (p<0.0001)... As a result of the changes in incision management practice, a total of 92 cesarean post-operative SSIs were avoided.... [Kmom note: All women with a BMI over 35 were considered high-risk for SSIs and routinely given the interventions listed.]
Incision Type in Obese Patients

Obstet Gynecol. 2003 Nov;102(5 Pt 1):952-6. Vertical skin incisions and wound complications in the obese parturient. Wall PD, Deucy EE, Glantz JC, Pressman EK. PMID: 14672469
...RESULTS: From 1994 to 2000, 239 women with a BMI greater than 35 undergoing a primary cesarean delivery were identified. The overall incidence of wound complications in this group of severely obese patients was 12.1%. Factors associated with wound complications included vertical skin incisions (odds ratio [OR] 12.4, P < .001) and endometritis (OR 3.4, P = .03)...Our data indicate that a vertical skin incision is associated with a higher rate of wound complications than a transverse incision.
J Matern Fetal Neonatal Med. 2012 Sep;25(9):1544-8. doi: 10.3109/14767058.2011.653422. Epub 2012 Feb 13. Risk factors for wound complications in morbidly obese women undergoing primary cesarean delivery. Thornburg LL, Linder MA, Durie DE, Walker B, Pressman EK, Glantz JC. PMID: 22233403
METHODS: Retrospective cohort study evaluating infectious and separation WC in morbidly obese (body mass index [BMI] > 35 kg/m(2)) women undergoing primary CD between January 1994 and December 2008...RESULTS: Of 623 women, low transverse skin incisions were performed in 588 (94.4%), vertical in 35 (7%). Overall WC rate was 13.5%, which varied by incision type (vertical 45.7% vs. 11.6% transverse; p < 0.01), but not BMI class. Incision type and unscheduled CD were associated with infection risk, while incision type, BMI, race and drain use were associated with wound separation. CONCLUSION: In morbidly obese women both infectious and separation type WC are more common in vertical than low transverse incisions; therefore transverse should be preferred.
Am J Obstet Gynecol. 2017 Jul;217(1):85. doi: 10.1016/j.ajog.2017.06.002. Removal notice to The relationship between primary cesarean delivery skin incision type and wound complications in women with morbid obesity: Am J Obstet Gynecol 2014;210:319.e1-4. Marrs CC, Moussa HN, Sibai BM, Blackwell SC. PMID: 28648694
...The original publication reported that univariate analysis showed that a vertical skin incision in obese women undergoing Cesarean delivery was associated with a higher odds ratio for wound complications than a transverse skin incision. Multivariable analyses showed a reversal of the association (i.e. the odds of wound complications were lower in women with a vertical skin incision). However, there was an error in the way the variable was entered in the logistic analysis. Re-analysis with the correct coding of the variable indicates that a transverse skin incision is associated with decreased odds of wound complication compared to a vertical skin incision. 
Obstet Gynecol. 2014 Aug;124(2 Pt 1):227-32. doi: 10.1097/AOG.0000000000000384. Extreme obesity and postcesarean maternal complications. Stamilio DM, Scifres CM. PMID: 25004353
...This was a secondary cohort analysis of a randomized controlled trial... We included 585 women in the analysis. Eighty-five patients (14.5%) had BMIs higher than 45. ...Obese patients were more likely to have a cesarean delivery after labor and have a vertical skin incision or classical uterine incision. After controlling for confounders, extremely obese patients had a twofold to fourfold increase in postoperative complications, including the primary infectious outcome (18.8%, adjusted OR 2.7, CI 1.2-6.1), wound infection (18.8%, adjusted OR 3.4, CI 1.4-8.0), and emergency department visit (23.1%, adjusted OR 2.2, CI 1.03-4.9)....
Am J Perinatol. 2016 Apr;33(5):463-72. doi: 10.1055/s-0035-1566000. Epub 2015 Oct 28. The Problem of the Pannus: Physician Preference Survey and a Review of the Literature on Cesarean Skin Incision in Morbidly Obese Women. Smid MC, Smiley SG, Schulkin J, Stamilio DM, Edwards RK, Stuebe AM. PMID: 26510932
This study aims to determine preferences of a nationally representative sample of obstetrician/gynecologists (OB/GYNs) regarding cesarean delivery (CD) incision practices for women with morbid obesity (body mass index ≥ 40 kg/m(2))... 247 OB/GYNs completed the survey (42% response rate). In nonemergency CD of morbidly obese women, 84% of physicians preferred a Pfannenstiel skin incision... In emergency CD, 66% preferred a Pfannenstiel incision... and 20% a vertical incision....
Obesity and Antibiotic Dosing 

Obstet Gynecol. 2011 Apr;117(4):877-82. doi: 10.1097/AOG.0b013e31820b95e4. Effects of maternal obesity on tissue concentrations of prophylactic cefazolin during cesarean delivery. Pevzner L, Swank M, Krepel C, Wing DA, Chan K, Edmiston CE Jr. PMID: 21422859
...METHODS:Twenty-nine patients scheduled for cesarean delivery were stratified according to body mass index (BMI) category, with 10 study participants classified as lean (BMI less than 30), 10 as obese (BMI 30-39.9), and nine as extremely obese (BMI 40 or higher). All patients were given a dose of 2 g cefazolin 30-60 minutes before skin incision...RESULTS: Cefazolin concentrations within adipose tissue obtained at skin incision were inversely proportional to maternal BMI (r=-0.67, P<.001)...Although all specimens demonstrated therapeutic cefazolin levels for gram-positive cocci (greater than 1 microgram/g), a considerable portion of obese and extremely obese did not achieve minimal inhibitory concentrations of greater than 4 micrograms/g for Gram-negative rods in adipose samples at skin incision (20% and 33.3%, respectively) or closure (20.0% and 44.4%, respectively) ...CONCLUSION: Pharmacokinetic analysis suggests that present antibiotic prophylaxis dosing may fail to provide adequate antimicrobial coverage in obese patients during cesarean delivery.
Am J Obstet Gynecol. 2015 Sep;213(3):415.e1-8. doi: 10.1016/j.ajog.2015.05.030. Epub 2015 May 21. Increased 3-gram cefazolin dosing for cesarean delivery prophylaxis in obese women. Swank ML, Wing DA, Nicolau DP, McNulty JA. PMID: 26003059
OBJECTIVE: The purpose of this study was to determine tissue concentrations of cefazolin after the administration of a 3-g prophylactic dose for cesarean delivery in obese women (body mass index [BMI] >30 kg/m(2)) and to compare these data with data for historic control subjects who received 2-g doses... RESULTS: Twenty-eight obese women were enrolled in the current study; 29 women were enrolled in the historic cohort. BMI had a proportionally inverse relationship on antibiotic concentrations. An increase of the cefazolin dose dampened this effect and improved the probability of reaching the recommended MIC of ≥8 μg/mL...With 2 g of cefazolin, only 20% of the cohort with a BMI of 30-40 kg/m(2) and none of the cohort with a BMI of >40 kg/m(2) reached an MIC of ≥8 μg/mL. With 3-g, all women with a BMI of 30-40 kg/m(2) reached target MIC values; 71% of the women with a BMI of >40 kg/m(2) attained this cutoff. CONCLUSION: Higher adipose concentrations of cefazolin were observed after the administration of an increased prophylactic dose. This concentration-based pharmacology study supports the use of 3 g of cefazolin at the time of cesarean delivery in obese women....
Obstet Gynecol. 2015 Oct;126(4):708-15. doi: 10.1097/AOG.0000000000001064. Obstetric Surgical Site Infections: 2 Grams Compared With 3 Grams of Cefazolin in Morbidly Obese Women. Ahmadzia HK, Patel EM, Joshi D, Liao C, Witter F, Heine RP, Coleman JS. PMID: 26348186
...A retrospective cohort study of morbidly obese pregnant women undergoing cesarean delivery was conducted at two tertiary care centers from 2008 to 2013. Exposure was defined as receiving 2 g compared with 3 g cefazolin preoperatively...There were 335 women included in the cohort with a median absolute weight of 310... pounds... There was no difference in surgical site infection among those women who received 2 g compared with 3 g cefazolin (13.1% [23/175] compared with 13.1% [21/160]; P=.996). Labor (crude odds ratio [OR] 2.31, 95% confidence interval [CI] 1.21-4.40), internal labor monitoring (OR 2.78, 1.45-5.31), blood loss greater than 1,500 mL (OR 2.15, 1.09-5.78), and staple closure (OR 2.2, 1.15-4.21) were associated with a surgical site infection among the entire cohort. After multivariable analysis, blood loss... (adjusted OR 3.32, 1.32-8.37) and staple closure (adjusted OR 2.45, 1.19-5.02) remained associated with an increased risk for a surgical site infection, whereas 3 g cefazolin still was not associated with reduced risk for a surgical site infection (adjusted OR 1.33, 0.64-2.74). CONCLUSION: In our multicenter retrospective cohort study, preoperative 3 g cefazolin prophylaxis administered to morbidly obese gravid patients did not reduce surgical site infections.
Obstet Gynecol Surv. 2017 Aug;72(8):500-510. doi: 10.1097/OGX.0000000000000469. Body Mass Index 50 kg/m2 and Beyond: Perioperative Care of Pregnant Women With Superobesity Undergoing Cesarean Delivery. Smid MC, Dotters-Katz SK, Silver RM, Kuller JA. PMID: 28817167
...Currently, 2% of pregnant women in the United States are superobese, and 50% will deliver via cesarean delivery. ... There is limited information to direct evidence-based care of superobese women who undergo cesarean delivery. Superobese women have a 30% to 50% risk of wound complications...Preoperative cefazolin with a 3-g dose, chlorhexidine skin preparation, and availability of adequate personnel for patient transfers are important evidence-directed approaches to reducing maternal and personnel morbidity. Postoperatively, early ambulation and chemical prophylaxis are reasonable, although there is a lack of evidence as to whether these measures prevent thromboembolic complications... Most evidence-directed recommendations for perioperative care are extrapolated from studies of obese women undergoing bariatric surgery. As the prevalence of reproductive-age women with superobesity increases, studies directed at this high-risk population are urgently needed.
JAMA. 2017 Sep 19;318(11):1026-1034. doi: 10.1001/jama.2017.10567. Effect of Post-Cesarean Delivery Oral Cephalexin and Metronidazole on Surgical Site Infection Among Obese Women: A Randomized Clinical Trial. Valent AM, DeArmond C, Houston JM, Reddy S, Masters HR, Gold A, Boldt M, DeFranco E, Evans AT, Warshak CR. PMID: 28975304
...Randomized, double-blind clinical trial comparing oral cephalexin and metronidazole vs placebo for 48 hours following cesarean delivery for the prevention of SSI in obese women (prepregnancy BMI ≥30) who had received standard intravenous preoperative cephalosporin prophylaxis. Randomization was stratified by intact vs rupture of membranes prior to delivery...Participants were randomly assigned to receive oral cephalexin, 500 mg, and metronidazole, 500 mg (n = 202 participants), vs identical-appearing placebo (n = 201 participants) every 8 hours for a total of 48 hours following cesarean delivery. ...RESULTS: ...Surgical site infection was diagnosed in 13 women (6.4%) in the cephalexin-metronidazole group vs 31 women (15.4%) in the placebo group (difference, 9.0% [95% CI, 2.9%-15.0%]; relative risk, 0.41 [95% CI, 0.22-0.77]; P = .01). ...CONCLUSIONS AND RELEVANCE: Among obese women undergoing cesarean delivery who received the standard preoperative cephalosporin prophylaxis, a postoperative 48-hour course of oral cephalexin and metronidazole, compared with placebo, reduced the rate of SSI within 30 days after delivery. For prevention of SSI among obese women after cesarean delivery, prophylactic oral cephalexin and metronidazole may be warranted.
Obesity and Sutures vs. Staples

Am J Perinatol. 2014 Apr;31(4):299-304. doi: 10.1055/s-0033-1348402. Epub 2013 Jun 13. Maternal obesity and risk of postcesarean wound complications. Conner SN, Verticchio JC, Tuuli MG, Odibo AO, Macones GA, Cahill AG. PMID: 23765707  Full text found here.
...STUDY DESIGN: We performed a retrospective cohort study of consecutive cesarean deliveries at a tertiary care facility from 2004 to 2008. Four comparison groups were defined by body mass index (BMI; kg/cm2): < 30 (n = 728), 30 to 39.9 (n = 1,087), 40 to 49.9 (n = 428), or ≥ 50 (n = 201). ...RESULTS: Of the 2,444 women with complete follow-up data, 266 (10.9%) developed a wound complication. Compared with nonobese women (6.6%), increasing BMI was associated with an increased risk of wound complications: BMI 30.0 to 39.9, 9.2%;... BMI 40.0 to 49.9, 16.8%;... BMI ≥ 50, 22.9%... Increasing BMI was also associated with increased rates of midline vertical incision, longer operative time, higher EBL [estimated blood loss], and lower rates of subcuticular skin closure....
J Perinatol. 2016 Oct;36(10):819-22. doi: 10.1038/jp.2016.89. Epub 2016 Jun 2. Wound complications in obese women after cesarean: a comparison of staples versus subcuticular suture. Zaki MN, Truong M, Pyra M, Kominiarek MA, Irwin T. PMID: 27253895
...We conducted a retrospective cohort study to compare wound complications between staples and subcuticular suture closure in women, with a prepregnancy BMI⩾30... after CD between 2006 and 2011 at an inner-city teaching hospital... RESULTS: Of the 1147 women included in the study, ...Women with staples had higher wound complications compared with sutures (22.0% versus 9.7%) with a 2.27 unadjusted relative risk (RR) (95% confidence interval (CI), 1.7 to 3.0) and 1.78 adjusted RR (95% CI, 1.27 to 2.49) after controlling for confounders in the final analysis, including vertical skin incisions. CONCLUSIONS: In obese women, skin closure with staples at the time of CD is associated with a higher rate of wound complications compared with subcuticular suture. Skin closure with subcuticular suture over staples should be considered in obese women undergoing a CD regardless of skin incision type.
Obesity and Thromboprophylaxis

J Perinatol. 2016 Feb;36(2):95-9. doi: 10.1038/jp.2015.130. Epub 2015 Dec 10. A randomized controlled trial of differing doses of postcesarean enoxaparin thromboprophylaxis in obese women. Stephenson ML, Serra AE, Neeper JM, Caballero DC, McNulty J. PMID: 26658126
...To compare two enoxaparin dosing strategies at achieving prophylactic anti-Xa levels in women with a body mass index (BMI) ⩾35 (kg m(-2)) postcesarean delivery. STUDY DESIGN: Women with BMI ⩾35 were randomized to receive prophylactic enoxaparin at a fixed dose of 40 mg daily or weight-based dosing of 0.5 mg kg(-1) twice daily. ...In the weight-based group, 88% (37/42) of the women reached prophylactic anti-Xa levels versus 14% (6/42) in the fixed dose group (odds ratio 44.4, 95% confidence interval 12.44, 158.48, P<0.001)...There were no venous thromboembolic or bleeding events requiring reoperation or transfusion in either group. CONCLUSION: Compared with fixed dosing daily, weight-based dosing twice daily more effectively achieved prophylactic anti-Xa levels without reaching the therapeutic range.
Obesity and Subcutaneous Tissue Approximation

Obstet Gynecol. 2004 May;103(5 Pt 1):974-80. Suture closure of subcutaneous fat and wound disruption after cesarean delivery: a meta-analysis. Chelmow D, Rodriguez EJ, Sabatini MM. PMID: 15121573  Full text here
...CONCLUSION: Suture closure of subcutaneous fat during cesarean delivery results in a 34% decrease in risk of wound disruption in women with fat thickness greater than 2 cm.
Obesity and Surgical Drains

Am J Obstet Gynecol. 2010 Sep;203(3):271.e1-7. doi: 10.1016/j.ajog.2010.06.049. Epub 2010 Aug 3. Complications of cesarean delivery in the massively obese parturient. Alanis MC, Villers MS, Law TL, Steadman EM, Robinson CJ. PMID: 20678746
...This was an institutional review board-approved retrospective study of massively obese women (body mass index, > or = 50 kg/m(2)) undergoing cesarean delivery... Fifty-eight of 194 patients (30%) had a wound complication...Subcutaneous drains and smoking, but not labor or ruptured membranes, were independently associated with wound complication after controlling for various confounders. Vertical abdominal incisions were associated with increased operative time, blood loss, and vertical hysterotomy. CONCLUSION: Women with a body mass index > or = 50 kg/m(2) have a much greater risk for cesarean wound complications than previously reported. Avoidance of subcutaneous drains and increased use of transverse abdominal wall incisions should be considered in massively obese parturients to reduce operative morbidity.
Obstet Gynecol. 2005 May;105(5 Pt 1):967-73. Subcutaneous tissue reapproximation, alone or in combination with drain, in obese women undergoing cesarean delivery. Ramsey PS, White AM, Guinn DA, Lu GC, Ramin SM, Davies JK, Neely CL, Newby C, Fonseca L, Case AS, Kaslow RA, Kirby RS, Rouse DJ, Hauth JC. PMID: 15863532
...We conducted a multicenter randomized trial of women undergoing cesarean delivery. Consenting women with 4 cm or more of subcutaneous thickness were randomized to either subcutaneous suture closure alone (n = 149) or suture plus drain (n = 131)...RESULTS: From April 2001 to July 2004, a total of 280 women were enrolled. Ninety-five percent of women (268/280) had a follow-up wound assessment...The composite wound morbidity rate was 17.4% (25/144) in the suture group and 22.7% (28/124) in the suture plus drain group (relative risk 1.3, 95% confidence interval 0.8-2.1)...CONCLUSION: The additional use of a subcutaneous drain along with a standard subcutaneous suture reapproximation technique is not effective for the prevention of wound complications in obese women undergoing cesarean delivery.
Negative Pressure Wound Therapy and Obesity

AJP Rep. 2017 Jul;7(3):e151-e157. doi: 10.1055/s-0037-1603956. Epub 2017 Jul 14. Closed-Incision Negative-Pressure Therapy in Obese Patients Undergoing Cesarean Delivery: A Randomized Controlled Trial. Gunatilake RP, Swamy GK, Brancazio LR, Smrtka MP, Thompson JL, Gilner JB, Gray BA, Heine RP. PMID: 28717587
...We compared surgical site occurrences (SSOs) in cesarean patients receiving closed-incision negative-pressure therapy (ciNPT) or standard-of-care (SOC) dressing. STUDY DESIGN: A single-center randomized controlled trial compared ciNPT (5-7 days) to SOC dressing (1-2 days) in obese women (body mass index [BMI] ≥ 35), undergoing cesarean delivery between 2012 and 2014...CONCLUSION: A trend in SSO reduction and a statistically significant reduction in postoperative pain and narcotic use was observed in women using ciNPT.
Obstet Gynecol. 2017 Nov;130(5):969-978. doi: 10.1097/AOG.0000000000002259. Prophylactic Negative Pressure Wound Therapy for Obese Women After Cesarean Delivery: A Systematic Review and Meta-analysis. Smid MC, Dotters-Katz SK, Grace M, Wright ST, Villers MS, Hardy-Fairbanks A, Stamilio DM. PMID: 29016508
...In the meta-analysis, there was no difference in primary composite outcome among those women with negative pressure wound therapy (16.8%) compared with those who had standard dressing (17.8%) (risk ratio 0.97, 95% CI 0.63-1.49)...CONCLUSION: Currently available evidence does not support negative pressure wound therapy use among obese women for cesarean wound complication prevention.
Morbidity of Multiple Cesareans in Obese Women

J Matern Fetal Neonatal Med. 2015 Jun;28(9):989-93. doi: 10.3109/14767058.2014.941284. Epub 2014 Jul 24. The effect of maternal obesity on outcomes in patients undergoing tertiary or higher cesarean delivery. Mourad M, Silverstein M, Bender S, Melka S, Klauser CK, Gupta S, Saltzman DH, Rebarber A, Fox NS. PMID: 25058127
...Retrospective cohort of patients cared for by a single MFM practice undergoing a tertiary or higher cesarean delivery from 2005 to 2013...The primary outcome was a composite of severe maternal morbidity (uterine rupture, hysterectomy, blood transfusion, cystotomy requiring repair, bowel injury requiring repair, intensive care unit admission, thrombosis, re-operation, or maternal death). RESULTS: ...The composite outcome was significantly higher in the obese group (6.8% versus 1.8%, p = 0.024, aOR 4.36, 95% CI 1.21, 15.75). The incidence of several individual adverse outcomes were also increased in obese women, including blood transfusion (4.1% versus 0.7%, p = 0.033, aOR 7.36, 95% CI 1.19, 45.34), wound separation or infection (20.5% versus 5.9%, p < 0.001, aOR 4.05, 95% CI 1.75, 9.36) and 1-min Apgar score less than 7 (6.8% versus 1.9%, p = 0.024, aOR 4.40, 95% CI 1.21, 15.94). CONCLUSIONS: In patients undergoing a tertiary or higher cesarean delivery without placenta previa or accreta, obesity increases the risk of adverse outcomes. Obese patients are at risk for blood transfusion, low 1-min Apgar scores and postoperative wound complications.