Seventh Annual Turkey Awards: Astronomical Cesarean Rates in Women of Size

Well, it's long past time for our seventh annual Well-Rounded Mama's Turkey Awards! Somehow 2014 got away from me, so we are doing this in spring of 2015, as our finale for Cesarean Awareness Month.

The Turkey Awards are the "prizes" I hand out to highlight fat-phobic treatment of people of size from care providers, biased attitudes or studies from researchers, or troubling trends in the care of fat pregnant women these days.

In past years, we've talked about:

1. fat-phobic care providers
2. scare-mongering and shaming tactic
3. jumping to conclusions about risks
4. scorched earth tactics
5. prenatal weight gain extremism
6. fat-phobic attitudes around treatment of PolyCystic Ovarian Syndrome (PCOS)

This year it's time to shine a critical spotlight on the astronomically high cesarean rates in high-BMI women in some studies, and the failure of some care providers to take any responsibility for the management policies that have led to these astoundingly-high rates.

Many studies decry the abysmally high c-section rates in "morbidly obese" women, but for the most part only use it to call for more stringent weight loss campaigns, rather than recognizing their own role in creating these rates.

These atrocious c-section rates will continue (and even escalate) until care providers can:

• Acknowledge their own responsibility in creating these high rates
• Examine objectively common protocols for managing pregnancy and birth in women of size and evaluate whether these protocols are helping or harming
• Find other tools for lowering cesarean rates besides expecting women to lose weight

This doesn't mean that women of size have no responsibility for their health habits. Of course they do, as all people do. Women should optimize their health habits before and during pregnancy in order to improve outcomes. There is nothing wrong with encouraging reasonable health habits.

But "obesity" is a complex thing. It can be the result of poor lifestyle choices, but often it is the result of genetics, medical conditions like PCOS or lipedema, or certain medications. Sometimes we don't know why some people are fat and others are not. What we DO know is that it is statistically very unlikely that most women of size will be able to "normalize" their BMI before pregnancy...or even close. 

If care providers are serious about lowering cesarean rates in women of size, they need to expand the discussion beyond the usual rhetoric of shaming, blaming, and putting women on diets. 

It's time for a more realistic approach that doesn't rely on finger-pointing and improbable weight loss expectations, but instead uses concrete steps that can be done right now, regardless of whether or not women lose weight. 

Unconscionably High Cesarean Rates

First, let's look at some studies that show just how bad the problem has gotten.

Check out this study from 2013 which documented cesarean rates in high-BMI women in Tennessee. Note the underlying high cesarean rates in every group in this institution; it's not just fat women that are getting cut. But then note how this cesarean-oriented culture results in especially high rates in "morbidly obese" women:

• "Underweight" women (BMI less than 18.5) -  26.0%
• "Normal Weight" women (BMI 18.6 - 24.9) -  31.4%
• "Overweight" women (BMI 25 - 29.9) -           39.1%
• "Obese" women (BMI 30 - 34.9) -                    40.8%
• "Morbidly Obese" women (BMI 40+) -            56.6%

This reminds me of a similar study from Kentucky, showing cesarean rates in morbidly obese women near 60% also.

You can find studies with even higher rates too, like this very large, multi-state study from more than a decade ago which found a c-section rate of 71% for women with a BMI of 52 or more.

Or a more recent study that found a nearly 70% c-section rate in women with a BMI of 35 or more.

Then there's this study from Michigan, which had a total cesarean rate of MORE THAN 80% for women with a BMI over 50. Seriously....they had a vaginal birth rate of only 19% in this group! Absolutely inexcusable. But of course the authors promptly blamed it on the women themselves and made an even stronger call for pressuring women for "weight control" before pregnancy.

I'm all for improving health before pregnancy, whatever your size, but this doesn't necessarily mean "weight control." I wish more care providers understood that the two things don't necessarily equate. I also wish they realized that these pushes for "weight control" often end up with rebound gain, making the patient fatter in the long run rather than thinner. When will doctors realize that the prescription they typically give for "getting healthier" actually often results in more weight rather than less?

But that's not what bothered me the most. What really bothers me is that none of these authors acknowledge IN ANY WAY that they or their policies could have any role in these insanely high cesarean rates. They only blame the women and call for weight control.

My question is...WHERE IS THE ACCOUNTABILITY FOR THESE EXTREME RATES? 

Lack of Accountability and Concern

Why aren't hospitals having their feet held to the fire for 60-80% c-section rates in obese women??? Why doesn't anyone care about all these women being cut?

Where is the concern for obese women's health with all this surgery? 

We know that surgery has more complications for high-BMI people; this is also true for cesareans. You'd think care providers would be doing all they could to lower cesarean rates rather than just passively accepting these sky-high rates and hoping against hope that fat women will lose weight before pregnancy next time.

Yes, we get it. As a group, fat women have more risks, more complications, and they are much harder to do surgery on if a cesarean is needed. I don't blame providers for being honest about the potential complications involved in serving high-BMI women and therefore wanting to see fewer extremely fat women because of the potential complications in attending them. I totally get that.

But some seem to use cesareans as a punishment for daring to be Pregnant While Fat. 

Many just sign fat women up for planned cesareans before labor even starts, or induce so many that it's no wonder their cesarean rate is so high. That's not good medicine. Providers are there to serve ALL women, even the more challenging cases, and to serve them with respectful care that doesn't add more risk.

The silence from researchers and care providers on this issue is deafening.

• Where is the research that questions such high cesarean rates in obese women? 
• Where are the community care providers who are protesting and saying that this rate of cesareans in women of size is totally unacceptable?
• Most importantly, where is the research that is actively trying to find ways to lower the cesarean rate in obese women?

The authors of studies like these throw up their hands like they are powerless against the tide of fatness and they have no choice but to cut because everyone knows that fatness interferes with the ability to give birth vaginally. These women brought it on themselves, right?

To which I say, BALONEY. 

Historically, fat women did not have such astronomically high cesarean rates, and often their cesarean rates were similar or slightly higher than "normal" BMI women. The picture is far different today.

One German study we discussed recently showed that while cesarean rates have increased in all groups over time, they've increased the most in "morbidly obese" women. Look at their comparison of cesarean rates between 1990 and 2012 by BMI group:

Category            1990           2012         Increase

Underweight       14.4%        27.9%       13.5%
Normal               16.1%        31.4%       15.3%
Overweight         19.5%       38.8%        19.3%
Obese I               22.3%       45.1%        22.8%
Obese II              25.0%       50.2%        25.2%
Obese III             26.9%       55.2%        28.3%

Cesarean rates have increased across the board in all groups, but the increase in cesarean rates in "normal" weight women was 15.3%, whereas the increase in Obese Class III women was 28.3%.

In just 22 years, the cesarean rate in Class III Obese women went from 26.9% to 55.2%.

Why? What changed? These stats compare women of the same size, so it wasn't the women who changed. Most likely it was the management of those women that changed, and the fear levels around their pregnancies.

If the cesarean rate in higher weight women has increased from 27% to 55% in 22 years, how far will it go in the next 20 years?

SOMETHING has to change in order to alter that trajectory. Let's start having a conversation about realistic things that can be done to change it.

Cesarean Practice Rate Variation Among Obese Women

As I've pointed out before, there was a large recent British study that found a 30% cesarean rate in "super-obese" women (BMI 50 or more) who were given a chance to labor. Yes, 70% of these super-obese women were able to give birth vaginally ─ when given the chance to do so. 

Yet hospitals in Kentucky and Tennessee, as cited above, had c-section rates of around 60%, nearly TWICE the British rate. And the Michigan study had rates even higher than that. Why?

These differences suggest that there are key differences in how high BMI women are being managed that is resulting in such wide variations in cesarean rates in this group, both over time and by location.

The good news is that means that there ARE things that can be done to lower the cesarean rate in higher weight women. So why isn't anyone studying what the Brits are doing that helps them have half the rate of c-sections in this group? (And I bet that their rates could be lowered, too, as the U.K. is certainly no haven for size-friendliness either.) Why isn't anyone studying what changed in the management of obese women in the previously-mentioned German  study that made their cesarean rates go up so much?

It's time for care providers to start focusing on the cesarean practice rate variation in obese women and learning from it.

Once we acknowledge that there is a wide range in the obese cesarean rate, we can more easily start studying the things that help lower the risk for cesarean in this group, and hospitals can work on meaningful changes that will improve outcomes. But I have yet to see one study that seriously addresses this issue.

Why Not Diets?

Sadly, the response of the obstetric community has mostly been one of shaming, blaming, and diets instead of willingness to look more closely at these patterns.

Of course, there are good providers are appalled at the poor treatment many women of size experience, and many try their hardest to provide gentle, respectful care to women of size. BRAVO to them.

However, too many providers still believe the myths around fatness and pregnancy, like the popular "soft tissue dystocia" theory. Many are convinced that the only real way to lower the cesarean rate in obese women is to get them to lose weight first.

Many will undoubtedly protest that it is a care provider's job to promote healthy habits and to help patients be healthier, so of course they should be pushing them to lose weight. After all, why not?

It's true that care providers should be promoting healthy habits...but it doesn't follow that losing weight is the result. This is part of the common misperception that fat people are only ever fat because they are "doing something wrong" and that fatness is always a voluntary choice based on laziness and lack of healthy habits.

Nope, obesity is far more complex than that ─ but that doesn't fit in with the narrative many care providers want to hear. They only want to blame fat people for their fatness, rather than acknowledging that the truth is much more tangled.

Should caregivers promote healthy habits? Absolutely ─ for women of all sizes. Programs that gently promote reasonable nutrition and exercise are fine, but they should apply to all women since poor lifestyle can be found in every body size. And contrary to public opinion, many fat people have very normal habits.

Let's stop buying into the illusion that promoting healthy habits will automatically result in permanent weight loss and a "normal" body size in everyone. It won't, and there is LOADS of research to support that.

While some providers acknowledge that "normalizing" BMI is very unlikely for most obese people, many still suggest pursuing a 5-10% weight loss. Some higher-weight people may choose to do this because some research suggests that a small weight loss can be at least temporarily beneficial.

However, the hard truth that most care providers don't want to face is that such weight loss often triggers weight cycling, which is a strong predictor of greater weight gain over time and which may also increase the risk for other health problems.

What care providers don't want to acknowledge is that even modest weight-loss attempts are basically a game of Russian Roulette, where high BMI people balance the possibility of temporary health improvements against the strong likelihood of regain and often, worsened health in the long run. 

While many people of size are happy to pursue weight loss, many with a strong history of weight cycling are not willing to risk further bouts on the yo-yo merry-go-round. This choice, too, must be respected. Improving the health and outcomes of obese people should not rest solely on weight loss.

Deal with the reality of the complexity of obesity and develop some alternative strategies to lower the cesarean rate in this group besides demanding weight loss.

Consider Other Solutions

If weight loss is the only tool in the toolbox for lowering the cesarean rate in obese women, then evidence suggests it's a doomed effort since most women don't lose weight permanently and many become pregnant unexpectedly without losing weight first. Cesarean prevention needs other tools in the toolkits besides weight loss.

Most importantly, caregivers need to acknowledge that how obese women are managed during labor significantly impacts the resulting cesarean rate. 

They need to actively pursue programs that try to reduce the cesarean rate in this group, and once they do, they need to evaluate the results of those programs to see if their efforts actually work. They also need to acknowledge the impact of their own beliefs and biases on cesarean rates and any intervention to reduce them.

Sometimes improvements may be less about the actual intervention itself and more about the providers' belief that it will improve outcome, which then changes their surgical threshold or use of other interventions.

For example, some studies have shown lower cesarean rates in obese women who gain less weight during pregnancy. The question is whether this is a real effect of lower weight gain itself, or whether the woman's lower weight gain then changed her provider's threshold for intervention. Caregivers are usually not blinded to a woman's weight gain; they may manage those who gained more weight with greater interventions and a different surgical threshold than those who gained less weight.

A similar effect may be true for those who manage to lose weight between pregnancies. Is it really the weight loss that makes a difference or is it the provider's perception of lower risk and therefore less use of interventions?

Providers' beliefs about fatness influence their management of fat women, and that in turn influences the cesarean rate. These factors must be untangled carefully in research if outcomes are to be improved.

The British and German studies discussed above show that cesarean rates do not have to be excessive in very obese women. It's time that a serious effort is made to actually lower c-section rates in higher-weight women, especially where they are particularly excessive. The good news is that a few providers have started to ask the important questions on how to do this.

Start with the Basics

To start lowering the cesarean rate for high-BMI women, care providers first need to start applying the lessons they have learned in reducing cesarean rates in average-sized women to the management of women of size.

For example, the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) recently recommended several steps to help lower the primary cesarean rate, including:

• Allowing prolonged latent (early) phase labor
• Considering cervical dilation of 6 cm (instead of 4 cm) as the start of active phase labor
• Allowing more time for labor to progress in the active phase
• Allowing women to push for at least two hours if they have delivered before, three hours if it’s their first delivery, and even longer in some situations, for example, with an epidural
• Using techniques to assist with vaginal delivery, which is the preferred method when possible. This may include the use of forceps, for example
• Encouraging patients to avoid excessive weight gain during pregnancy

These steps are widely acknowledged as helping to lower cesarean rates, but somehow are rarely applied to women of size when they labor (except, of course, the advice to avoid excessive weight gain, which women of size hear constantly).

The first step towards lowering cesarean rates in obese women is to allow more time in labor as long as mother and baby are doing well. 

Most cesareans performed on high BMI women are done in the first stage of labor, not once these women reach the pushing stage. Studies have shown that labor is often terminated earlier in women of size, sometimes before active labor is even really achieved, and that more patience in labor may be particularly important with obese patients.

One famous VBAC and obesity study, for example, found only a 13% VBAC rate in women over 300 lbs. and has been widely used to deny VBACs to women of size. When you look more closely at the data, however, you see that nearly all these women had their VBACs induced (which decreases the chances of success) and that their trials of labor were terminated at an average of 4.5 cm of dilation, which was barely into active labor even by the definitions of the time (4 cm). By the new guidelines, they wouldn't even have been considered in active labor. The providers paid lip service to the idea of VBAC in these women but barely gave them a chance to really labor.

Happily, a few researchers have begun to encourage allowing more time in labor for women of size. That's a great step in the right direction but we need more than a vague theoretical encouragement. Most providers don't follow the expanded guidelines yet, and particularly not for women of size. Hospitals need to develop accountability programs where they track the labors of high BMI women to see if they are being given adequate time in labor before surgical intervention.

Another important idea is to increase doula utilization among women of size. While the ACOG/SMFM document didn't list doula support in their top recommendations for preventing primary cesareans, they do acknowledge later on that doulas/continuous labor support is one of the most effective and least interventive ways to lower the cesarean rate, stating:

Published data indicate that one of the most effective tools to improve labor and delivery outcomes is the continuous presence of support personnel, such as a doula. A Cochrane meta-analysis of 12 trials and more than 15,000 women demonstrated that the presence of continuous one-on-one support during labor and delivery was associated with improved patient satisfaction and a statistically significant reduction in the rate of cesarean delivery. Given that there are no associated measurable harms, this resource is probably underutilized.

Care providers should be encouraging higher-weight women to hire doulas and helping establish programs for low-cost doula support for those who cannot afford a private doula. Yet many women of size go without doula support, despite consumer-based programs to connect them with size-friendly doulas. Doula support is underutilized by women of size; this is an area ripe for change.

Interventions for big babies are another major factor driving cesarean rates in obese women. In my many years of collecting the birth stories of women of size, I've noticed that many fat women are pressured into planned cesareans or inductions based on dubious fetal weight estimates. These interventions have not been shown to improve the outcome and often worsen it, yet they are still extremely common interventions in higher-weight women.

In one of my favorite parts of the consensus statement, ACOG and SMFM state (my emphasis):

Suspected fetal macrosomia is not an indication for delivery and rarely is an indication for cesarean delivery. To avoid potential birth trauma, the College recommends that cesarean delivery be limited to estimated fetal weights of at least 5,000 g in women without diabetes and at least 4,500 g in women with diabetes...Screening ultrasonography performed late in pregnancy has been associated with the unintended consequence of increased cesarean delivery with no evidence of neonatal benefit. Thus, ultrasonography for estimated fetal weight in the third trimester should be used sparingly and with clear indications.

They stop just short of telling doctors to STOP doing fetal weight estimations late in pregnancy, but they are certainly hinting broadly in that direction. And they are pretty clear that barring a very big baby (~11 lbs.) in a non-diabetic woman (or nearly 10 lbs. in a diabetic mother), doctors should not be performing a cesarean for "big baby." Yet care providers routinely do fetal weight estimations in obese women and then scare them into having a planned cesarean or induction based on the results.

So right there are three major things that ACOG/SFMFM recommend to lower the cesarean rate that probably are particularly applicable to high BMI women. Yet far too often, caregivers apply these recommendations to other women but not to women of size.

It's past time for caregivers to apply their own advice to the management of obese women too.

Re-examine Management Practices of Obese Women

The suggestions from ACOG and SFMFM are good starts, but they don't go far enough. We need a plan of action specific to higher-weight women to reduce cesarean rates in this group.

The problem is that all we have is guesswork to guide us in how to do this. There is NO study that has prospectively studied a strategy to lower the cesarean rate in high BMI women...and isn't that fact alone quite telling?

Given cesarean rates of 50%, 60%, 70%, and even 80% in this group, not to mention the higher complication rates of people of size after surgery, why hasn't this been studied?

Thankfully, a few studies in recent years have made some suggestions by extrapolating from what data we do have. Based on the evidence, my suggestions for lowering the cesarean rate in women of size would include:

• A strong emphasis on preventing the first cesarean, especially scheduled cesareans that occur before labor. There is often an assumption that fat women can't birth vaginally, so an "elective" cesarean is often planned, even in those who are not first-time mothers. But research shows that many higher-weight women can birth vaginally when allowed to labor

• Less early induction of labor unless it is truly medically indicated. As we discussed recently, obese women are often induced at extremely high rates; many of these are based more on fear than on true medical necessity. Research suggests that high induction rates are the beginning of high cesarean rates, and that when induction is controlled for, the differences in cesarean rates are much smaller or disappear entirely. Therefore, reducing non-indicated inductions will probably help reduce cesarean rates in this group

• Dating pregnancies more accurately in women of size with longer menstrual cycles. Many inductions in obese women are related to "postdates" pregnancies. Many of these may not actually be postdates at all because providers did not adjust for a longer menstrual cycle

• When induction is used, wait until the mother's cervix is ripe and ready for labor. Research strongly suggests that obese women are often induced when their cervix is less ripe and that this is linked to the higher failure rate of induction of labor in this group

• Reduction in the overuse of common interventions in obese women, like early breaking of water, early epidurals, and routine pitocin augmentation. For example, some research suggests that keeping the waters intact early in labor may help lower chances for a primary cesarean. Re-examine whether these common protocols for managing labor in women of size actually help or hurt

• Encouraging women of size to stay home longer in early labor, since research shows that coming into the hospital too early is strongly associated with higher intervention and higher cesarean rates. Yet women of size are often hospitalized earlier in labor. Since obese women tend to have longer and slower-moving labors on average, and since doctors often have a lower threshold for surgical intervention in this group, going in too early may be particularly harmful

• Giving women of size MUCH more time and patience in labor. As discussed above, obese women have a slower dilation curve and a longer first stage of labor. They may simply need extra time in labor before surgical intervention

• More utilization of midwifery care for obese women with minimal health complications, since midwifery care has often been shown to lower cesarean section rates. Yet the current trend is to force even healthy obese women with no complications into the care of obstetricians and high-intervention bariatric obstetrics specialty centers. Recognize that many otherwise-healthy obese women have generally good outcomes in pregnancy and can benefit from midwifery care

• Strongly encouraging use of doulas and professional labor support for women of size. As noted above, labor support has been shown to decrease the rate of cesareans in a number of studies. If a woman of size cannot afford her own doula, make low-cost or free doulas available 

• A re-emphasis on the importance of properly-sized equipment like blood pressure cuffs, since miscuffing remains a problem and anecdotal evidence suggests it sometimes results in cesareans, early inductions, or other interventions for falsely high blood pressure

• More attention to preventing and treating fetal malposition in women of size (who may be more at risk for fetal malpositions). The utility of regular chiropractic care in this group should be studied, and more caregivers should be trained in how to turn malpositioned babies during labor, as this has been shown to significantly reduce cesarean rates

• More freedom of movement in labor and utilization of alternative positions in pushing, instead of immobilizing the obese woman in bed. Research shows that a more upright position in labor can shorten labor and lower the risk for cesarean, and alternative birth positions may also help create more space in the pelvis or even help encourage a malpositioned baby to turn

• Encouragement of alternative methods of pain relief, including utilization of immersion in water (many hospitals strongly encourage or require early epidurals in women of size; women of size are not permitted to access birthing tubs in many hospitals)

• Less use of late ultrasounds for estimating fetal weight, as noted in the ACOG/SFMFM guidelines above, because they tend to be inaccurate, do not improve outcome, and have been shown to increase the cesarean rate independent of actual birth weight

• A revival of VBAC access for high BMI women, and more patience during their VBAC "trial of labor." Many obese women are not "allowed" to VBAC or are talked out of it. Even when they try a VBAC, induction is common, which decreases the chance of VBAC and may increase the chance for uterine rupture. In addition, more than half of their VBAC labors are cut short, often before they even reach active labor. More support for a VBAC trial of labor, fewer inductions, and a lot more patience during labor is needed to help reduce the high rate of repeat cesareans in women of size

Summary

Research is clear that while cesareans can save lives when used appropriately, they also present more harm than benefit when used too liberally.

The risks of cesareans are particularly strong in obese women, yet cesarean rates in this group have been reaching unconscionable heights lately. Rates of 50-80% are not uncommon. Although some of these cesareans are medically necessary, it's very doubtful that all ─ or even most ─ of them are.

Most care providers and researchers shrug off the extreme cesarean rates in women of size as a natural consequence of their obesity, and imply that this is simply the price they pay for daring to have a baby without losing weight first. They call for increased weight loss interventions before pregnancy rather than looking more deeply into the issue.

But focusing on weight loss to lower the cesarean rate will not result in much change because of the high failure rate of most weight loss attempts. In addition, it may result in more obesity rather than less for many women. Instead, re-evaluating how obese women are managed in labor can likely make a bigger dent in cesarean rates.

Historically, cesarean rates in higher-weight women were much lower than they are today. The cesarean rate has increased markedly in obese women in recent years, and there is a great deal of variation in the obese cesarean rate between institutions. This means that many fat women can give birth vaginally under the right conditions, and a high cesarean rate is not an inevitable outcome of obesity. It also likely means that there are ways to lower the cesarean rate in higher-weight women ─ if we are willing to study how and make change a priority.

Far too many of the cesareans in women of size today are “iatrogenic”— that is, influenced more by the attitudes and management protocols of the care providers than by the woman’s size. Far too many high BMI women are sectioned before labor even starts, induced before their bodies are ready, or have their labors cut short because of impatience or fear. But research has shown that women of size can give birth vaginally if they are just given a real chance to do so.

With a little research and some brutally honest introspection about management of this group, the cesarean rate in women of size can likely be reduced considerably. A few brave researchers have begun to speak out about this, but others continue to hide their heads in the sand and make excuses.

It's time for care providers to be held accountable for astronomical cesarean rates in women of size. And it's long past time for them to start actively working on ways to lower the cesarean rates in obese women besides focusing on weight loss.

References

Extreme Cesarean Rates in Women of Size

Tenn Med. 2013 Jan;106(1):35-7, 42. Association between cesarean delivery rate and body mass index. Berendzen JA, Howard BC. PMID: 23477241

...Twenty-six percent of underweight and 31.4 percent of normal weight women required cesarean delivery, while 39.1 percent of overweight, 40.8 percent of obese and 56.6 percent of morbidly obese women required cesarean delivery....

Am J Perinatol. 2011 Oct;28(9):729-34. doi: 10.1055/s-0031-1280852. Epub 2011 Jun 9. Extreme morbid obesity and labor outcome in nulliparous women at term. Garabedian MJ1, Williams CM, Pearce CF, Lain KY, Hansen WF. PMID: 21660900

...Using Kentucky birth certificate data...we examined the prevalence of CD by body mass index (BMI; in kg/m2)...CD was most common among women with a prepregnancy BMI ≥ 50 (56.1%)....

Obstet Gynecol. 2014 May;123 Suppl 1:159S-60S. doi: 10.1097/01.AOG.0000447159.35865.07. Perinatal outcomes in the super obese: a community hospital experience. Papp MM1, Lindsay A, Mariona F, Chatterjee S. PMID: 24770057

...Ongoing observational study involving pregnant women with body mass index equal or above 50 kg/m. The study was approved by the Wayne State University institutional review board...A total of 44.24% were delivered by primary cesarean delivery, 36% by repeat cesarean delivery, and 19% by vaginal delivery...[Kmom note: That's an 80% cesarean rate!] Public health officials and clinicians must join efforts to increase the population awareness of the implications of obesity during pregnancy and the postpartum period. The effect of maternal obesity on the offspring should prompt a community effort to improve preconception health and weight control to improve the maternal and neonatal health.

Am J Obstet Gynecol. 2012 May;206(5):417.e1-6. doi: 10.1016/j.ajog.2012.02.037. Epub 2012 Mar 7.
Maternal superobesity and perinatal outcomes. Marshall NE1, Guild C, Cheng YW, Caughey AB, Halloran DR. PMID: 22542116

OBJECTIVE: The purpose of this study was to determine the effect of maternal superobesity (body mass index [BMI], ≥ 50 kg/m(2)) compared with morbid obesity (BMI, 40-49.9 kg/m(2)) or obesity (BMI, 30-39.9 kg/m(2)) on perinatal outcomes. STUDY DESIGN: We conducted a retrospective cohort study of birth records that were linked to hospital discharge data for all liveborn singleton term infants who were born to obese Missouri residents from 2000-2006. We excluded major congenital anomalies and women with diabetes mellitus or chronic hypertension. RESULTS: There were 64,272 births that met the study criteria, which included 1185 superobese mothers (1.8%). Superobese women were significantly more likely than obese women to have preeclampsia (adjusted relative risk [aRR], 1.7; 95% confidence interval [CI], 1.4-2.1), macrosomia (aRR, 1.8; 95% CI, 1.3-2.5), and cesarean delivery (aRR, 1.8; 95% CI, 1.5-2.1). Almost one-half of all superobese women (49.1%) delivered by cesarean section, and 33.8% of superobese nulliparous women underwent scheduled primary cesarean delivery....

BJOG. 2011 Mar;118(4):480-7. doi: 10.1111/j.1471-0528.2010.02832.x. Epub 2011 Jan 18. Planned vaginal delivery or planned caesarean delivery in women with extreme obesity. Homer CS1, Kurinczuk JJ, Spark P, Brocklehurst P, Knight M. PMID: 21244616

OBJECTIVE: To compare the outcomes of planned vaginal versus planned caesarean delivery in a cohort of extremely obese women (body mass index ≥ 50 kg/m(2))...Five hundred and ninety-one extremely obese women delivering in the UK between September 2007 and August 2008...This study does not provide evidence to support a routine policy of caesarean delivery for extremely obese women on the basis of concern about higher rates of delivery complications, but does support a policy of individualised decision-making on the mode of delivery based on a thorough assessment of potential risk factors for poor delivery outcomes. [Kmom note: The cesarean rate was 30% in women with a BMI of 50+ who were allowed to labor.]

Lowering Cesarean Rates in Obese Women

J Midwifery Womens Health. 2014 Jan 8. doi: 10.1111/jmwh.12073. [Epub ahead of print] Intrapartum Management Associated with Obesity in Nulliparous Women. Carlson NS, Lowe NK. PMID: 24400789

...Nulliparous obese women are at higher risk for unplanned cesarean birth when compared with their normal-weight counterparts, and much of this increased risk is associated with labor management differences...Intrapartum interventions used significantly more often for healthy, obese nulliparous women when compared with normal-weight women were induction of labor, augmentation of labor, and cesarean birth. It is unclear if assisted vaginal birth occurs more frequently among obese women. Epidural anesthesia, artificial rupture of membranes prior to 6 cm of cervical dilation, and early hospital admission were shown in separate studies to be used more often in obese women. Intrapartum interventions were used more frequently in obese women in a dose-dependent manner by body mass index...Implications for clinical practice from this systematic review are that healthy, nulliparous obese women are exposed to common intrapartum interventions more often than normal-weight women. In the absence of evidence on the use of appropriate use of intrapartum interventions in this population, health care providers should carefully monitor management choices when working with healthy, nulliparous obese women.

J Obstet Gynaecol Can. 2011 May;33(5):443-8. Higher caesarean section rates in women with higher body mass index: are we managing labour differently? Abenhaim HA, Benjamin A. PMID: 21639963

BACKGROUND: Higher body mass index has been associated with an increased risk of Caesarean section. The effect of differences in labour management on this association has not yet been evaluated. METHODS: We conducted a cohort study using data from the McGill Obstetrics and Neonatal Database for deliveries taking place during a 10-year period...RESULTS: Data were available for 11 922 women, of whom 2289 women had normal weight, 5663 were overweight, 3730 were obese, and 240 were morbidly obese. After adjustment for known confounding variables, increased BMI category was associated with an overall increase in the use of oxytocin and in the use of epidural analgesia, and with a decrease in use of forceps and vacuum extraction among second stage deliveries. Higher BMI was also found to be associated with earlier decisions to perform a Caesarean section in the second stage of labour. When adjusted for these differences in the management of labour, the increasing rate of Caesarean section observed with increasing BMI category was markedly attenuated (P less than 0.001). CONCLUSION: Women with an increased BMI are managed differently in labour than women of normal weight. This difference in management in part explains the increased rate of Caesarean section observed with higher BMI. 

J Matern Fetal Neonatal Med. 2013 Apr;26(6):547-51. doi: 10.3109/14767058.2012.745506. Epub 2012 Nov 28. Cesarean delivery in obese women: a comprehensive review. Wispelwey BP1, Sheiner E. PMID: 23130683

...A thorough review of the literature indicates that a decreased cervical dilation rate, an increased induction rate, the presence of comorbid conditions, concern about shoulder dystocia, and weight gain in excess of recommendations during pregnancy all may contribute to the high rate of CD in obese women. Obese women are at increased risk of CD-related complications including anesthetic complications, wound complications, venous thromboembolism (VTE), and failure of vaginal birth after CD. CONCLUSIONS: Given the excess risks associated with CD in obese women, and that some of the rationale for the procedure (e.g. slower labor, concern about shoulder dystocia) may not be justified based on current evidence, a reassessment of the threshold at which obese women are recommended for CD is necessary. 

Induction of Labor and Cesareans in Women of Size

Am J Obstet Gynecol. 2014 Aug 6. pii: S0002-9378(14)00814-X. doi: 10.1016/j.ajog.2014.08.002. The risk of prelabor and intrapartum cesarean delivery among overweight and obese women: possible preventive actions. Hermann M1, Le Ray C2, Blondel B3, Goffinet F2, Zeitlin J3. PMID: 25108139

...We modeled relative risks (RRs) and risk differences of prelabor and intrapartum cesarean delivery by prepregnancy body mass index (obese, ≥30 kg/m2; overweight, 25-29.9 kg/m2; normal weight, 18.5-24.9 kg/m2) in a nationally representative sample of 12,297 French women...Risks of prelabor cesarean delivery were elevated only for obese multiparous women. This reflected not only a higher prevalence of previous cesarean delivery (26.4% vs 17.9% for normal-weight women) but also higher risks of prelabor cesarean delivery for multiparous women with no previous cesarean delivery after adjustment for medico-obstetric factors (RR, 1.82; 95% confidence interval [CI], 1.25-2.64)... Increased intrapartum cesarean delivery risks for primiparous women were related to more frequent labor induction (42.6% vs 23.8% for normal-weight women). CONCLUSION: It may be possible to reduce primary and thus repeat cesarean delivery rates among obese women by preventive actions targeting labor induction in primiparous women and prelabor cesarean deliveries in multiparous women. Further research is needed on the impact of limiting inductions on cesarean delivery risks for obese primiparous women.

Acta Obstet Gynecol Scand. 2013 Dec;92(12):1414-8. doi: 10.1111/aogs.12263. Maternal obesity and induction of labor. O'Dwyer V1, O'Kelly S, Monaghan B, Rowan A, Farah N, Turner MJ. PMID: 24116732

...Compared with women with a normal BMI, obese primigravidas but not obese multigravidas were more likely to have labor induced...In obese primigravidas, induction of labor was also more likely to be associated with other interventions such as epidural analgesia, fetal blood sampling and emergency cesarean section. In contrast, induction of labor in obese multigravidas was not only less common but also not associated with an increase in other interventions compared with multigravidas with a normal BMI. CONCLUSIONS: Due to the short-term and long-term implications of an unsuccessful induction in an obese primigravida, we recommend that induction of labor should only be undertaken for strict obstetric indications after careful consideration by an experienced clinician.

BMC Pregnancy Childbirth. 2014 Dec 20;14(1):422. [Epub ahead of print] Pre-pregnancy Body Mass Index (BMI) and delivery outcomes in a Canadian population. Vinturache A, Moledina N, McDonald S, Slater D, Tough S. PMID:25528667

...This study is a secondary analysis of the All Our Babies Cohort, a prospective, community-based pregnancy cohort in Calgary, Alberta...(n=1996)...Spontaneous onset of labour was recorded in 71.2% of women with normal pre-pregnancy BMI, whereas 39.3% of overweight and 49% of obese women had their labour induced. For women with spontaneous labour, pre-pregnancy BMI was not a significant risk factor for mode of delivery, controlling for covariates. Among women with induced labor, obesity was a significant risk factor for delivery by C-section (adjusted OR 2.2; CI 1.2-4.1)....

Am J Perinatol. 2013 Jan;30(1):75-80. doi: 10.1055/s-0032-1322510. Epub 2012 Jul 26. Interaction between maternal obesity and Bishop score in predicting successful induction of labor in term, nulliparous patients. Zelig CM1, Nichols SF, Dolinsky BM, Hecht MW, Napolitano PG. PMID: 22836819

STUDY DESIGN: Retrospective cohort study. Prospectively collected database utilized to determine the optimum Bishop score within each prepregnancy body mass index (BMI) category of term, nulliparous patients undergoing IOL....For the total group (n = 696), Bishop score ≥ 5 was most predictive of success (75% versus 56%, p < 0.0001). Within each BMI category, Bishop score ≥ 5 remained most predictive...CONCLUSION: The optimum Bishop score for predicting successful IOL in nulliparous patients was 5 regardless of BMI class. The higher IOL failure rate observed in obese women was associated with lower starting Bishop scores and was compounded by higher failure rates in obese women with Bishop scores < 3.

Aust N Z J Obstet Gynaecol. 2011 Apr;51(2):172-4. Impact of morbid obesity on the mode of delivery and obstetric outcome in nulliparous singleton pregnancy and the implications for rural maternity services. Green C, Shaker D. PMID: 21466521

...We conclude that morbid obesity is associated with a significantly higher risk of pre-existing medical conditions, developing antenatal complications, induction of labour, caesarean section and greater birth weight. However, there was no significant difference in caesarean section rates when adjusted for induction of labour....

Longer Labors, More Patience Needed

Am J Perinatol. 2012 Feb;29(2):127-32. doi: 10.1055/s-0031-1295653. Epub 2011 Nov 21. Effect of obesity on length of labor in nulliparous women. Hilliard AM1, Chauhan SP, Zhao Y, Rankins NC. PMID: 22105434

We compared the duration of labor among nulliparous women with varying body mass index (BMI). Laboring nulliparous women at >37 weeks were included. First visit BMI was used to categorize weight as normal (≤24), overweight (25 to 29.9), or obese (≥30 kg/m(2))...Duration of first stage of labor was significantly longer for obese versus normal-weight women (26.76 ± 0.77 versus 23.87 ± 0.66 hours; p = 0.024) but not between normal versus overweight women (p = 1.00) or overweight versus obese women (p = 0.114). The cesarean delivery rate was significantly different in the three groups (p = 0.0001), highest among obese (47%) and lowest in normal-weight women (24%). When adjusted for age, hypertension, and induction, the likelihood of completing stage I was significantly less among obese nulliparous than those with BMI < 24 kg/m(2) (hazard ratio 0.73, 95% confidence intervals 0.54, 0.99). Compared with those with BMI < 24, the duration of stage I is significantly longer among obese women, even when adjusted for maternal age, induction, and hypertension.

Am J Obstet Gynecol. 2011 Sep;205(3):244.e1-8. doi: 10.1016/j.ajog.2011.06.014. Epub 2011 Jun 23. Contemporary labor patterns: the impact of maternal body mass index. Kominiarek MA1, Zhang J, Vanveldhuisen P, Troendle J, Beaver J, Hibbard JU. PMID: 21798510

...A total of 118,978 gravidas with a singleton term cephalic gestation were studied. Repeated-measures analysis constructed mean labor curves by parity and BMI categories for those who reached 10 cm. Interval-censored regression analysis determined median traverse times, adjusting for covariates in vaginal deliveries and intrapartum cesareans. RESULTS: In the labor curves, the time difference to reach 10 cm was 1.2 hours from the lowest to highest BMI category for nulliparas. Multiparas entered active phase by 6 cm, but reaching this point took longer for BMI ≥40.0 (3.4 hours) compared to BMI <25.0 (2.4 hours). Progression by centimeter (P < .001 for nulliparas) and from 4-10 cm (P < .001 for nulliparas and multiparas) increased as BMI increased. Second stage length, with and without an epidural, was similar among BMI categories for nulliparas (P > .05) but decreased as BMI increased for multiparas (P < .001). CONCLUSION: Labor proceeds more slowly as BMI increases, suggesting that labor management be altered to allow longer time for these differences.

Eur J Obstet Gynecol Reprod Biol. 2013 Nov;171(1):49-53. doi: 10.1016/j.ejogrb.2013.08.021. Epub 2013 Aug 29. Maternal body mass index and duration of labor. Carlhäll S1, Källén K, Blomberg M. PMID: 24041847

Historical prospective cohort study including 63,829 nulliparous women with a singleton pregnancy and a spontaneous onset of labor, who delivered between January 1, 1995 and December 31, 2009...Overweight and obese women were compared to normal weight women regarding duration of active labor. Adjustments were made for year of delivery, maternal age and infant birth weight. RESULTS: The median duration of labor was significantly longer in obese women (class I obesity (BMI 30-34.9) = 9.1h, class II obesity (BMI 35-39.9) = 9.2h and class III obesity (BMI > 40) = 9.8h) compared to normal-weight women (BMI 18.5-24.9) = 8.8h (p < 0.001). The risk of labor lasting more than 12h increased with increasing maternal BMI: OR 1.04 (1.01-1.06) (OR per 5-units BMI-increase).The risk of labor lasting more than 12h or emergency cesarean section within 12h, compared to vaginal deliveries within 12h, increased with increasing maternal BMI. Duration of the second stage of labor was significantly shorter in obese women: in class III obesity the median value was 0.45 h compared to normal weight women, 0.55 h (p < 0.001). CONCLUSION: In nulliparous women with a spontaneous onset of labor, duration of the active phase of labor increased significantly with increasing maternal BMI. Once obese women reach the second stage they deliver more quickly than normal weight women, which implies that the risk of prolonged labor is restricted to the first stage of labor. It is clinically important to consider the prolonged first stage of labor in obese women, for example when diagnosing first stage labor arrest, in order to optimize management of this rapidly growing at-risk group of women. Thus, it might be reasonable to adapt the considered upper limit for duration of labor, according to maternal BMI.