Friday, June 27, 2014

Canning Books for Beginners

Image by Carter Housh

It's that time of year, when all the bounty of summer fruits are starting to roll in. Strawberries are in, rhubarb is in, the raspberries have just sprung to fruition, and cherries are hitting full force. Blueberries are just around the corner, and then it's time for plums. Yummm!

For me, that means it's time to start canning in order to preserve all these delicious fruits so I can enjoy them next winter too.

This is not something I grew up doing or learned from my mother; I had to learn it on my own. I came to it only in middle age, but it's a skill I'm determined to teach all my children because I think it's something everyone should know how to do.

If for no other reason, people should know how to preserve food so they have some emergency food on hand that doesn't depend on a refrigerator or freezer to keep it safe. And of course it's great to have these summer foods available to eat out of season, and they make great homemade gifts. But the best reason is because these foods just taste delicious!

So let's talk about the very easiest foods to can, jams and preserves, and the best books for learning how to prepare these.

Canning Books for Jams

When I was first learning how to can, I looked for a book that was quick and easy to understand, had great diagrams and instructions, and which had a lot of interesting recipes.

I found quite a number of good canning books and resources out there. Each one had something different to recommend it. Here are the best ones for beginners.

Put 'Em Up by Sherri Brooks Vinton is my favorite canning book and the one I recommend to beginners. I find the explanations very clear and concise, with some of the most clear illustrations of the process I've seen. When I was a beginner, this was the book that was most helpful to me.

I also liked that she organized the book by types of produce, so if cherries are in season and you are looking for something new to do with your overload of fresh cherries, you just turn to the "cherry" section of the book (which is clearly labeled and easy to find). That is really helpful. Many canning books are not organized like this.

The author has a great sequel too, just for fruits, with further recipes and hints on how to use them. And she now has a Preserving Answer Book, to answer common questions about canning, drying, freezing, etc. for those fairly new to food preservation.

One of the most common canning books, of course, is the Ball Blue Book Guide to Preserving and the Ball Complete Book of Home Preserving. Its companion website is, and it has a great guide to getting started with canning if you want to learn about canning without having to spend the money to buy a book.

This book is the classic canning book, and all its recipes have been extensively tested for safety. It's been around forever so it's got lots of time-tested recipes that have been favorites for generations. It goes far beyond the basic jam recipes included in most books and has recipes for many other types of foods besides jams.

A newer canning book that many people seem to like is Food In Jars by Marisa McClellan. The author has an excellent blog from which the book sprang. It has lots of interesting hints for canning and links to unusual products like special canning jars.

One interesting thing about Food In Jars recipes is that they often have unusual flavor combinations that go beyond the usual basic recipes found in most books. She typically does not use pectin in her recipes, but teaches the old-fashioned cook-em-till-they-set method. She has a great Canning 101 section on her blog where she answers a lot of questions about canning technique and safety.

The author has also written Preserving By The Pint, which specializes in canning recipes for very small batches, which can seem more do-able to the beginning canner since no special equipment and no huge pots of water are needed. You don't need to buy big batches of fruit and you end up with only a few jars to store, which is important if you have only limited storage. Most canning recipes were written for women with large families to feed; this is the scaled-down version for folks with very small families, not much time, or limited storage.

Another bonus is that the author does a lot of touring and offers classes all over the country teaching many of the recipes used in her book. That's good marketing and it helps a lot of people who feel insecure with canning to get past the fear and start doing it.

Another book which might be really handy for some is Preserving with Pomona's Pectin by Allison Carroll Duffy. This book specializes in recipes using Pomona's Pectin, which is a somewhat harder-to-find pectin but which offers the distinct advantage of being able to adjust the sugar content in a recipe.

With most other pectins, you have very little flexibility about how much sugar to use in a recipe. The full-sugar pectins use insane amounts of sugar in their recipes; usually far more sugar than fruit. Even the "reduced sugar" pectins (like Sure-Jell in the pink box) still use quite a bit of sugar.

But Pomona's Pectin works differently than other pectins. It doesn't need sugar to help "gel" the jam; it uses calcium water instead to get the gel. This means that the sugar content of these jams can be adjusted to your heart's content. You can use as much or as little as you prefer, and you can use honey, agave syrup, fruit juice, or artificial sweeteners to sweeten your jam instead of sugar. If you are one of the many people trying to reduce the sugar content in your diet for health reasons, this is a great option to have.

Pomona's Pectin offers a lot more flexibility than other pectins, but it has a little steeper learning curve than the full-sugar pectins. Having a book that discusses the process of using this pectin in minute detail can be useful for those new to canning with Pomona's Pectin.


There are many, many great canning books available out there, but these are some of the best canning books for beginners. Youtube also has many video tutorials available on canning, and you can find many canning instructional DVDs as well.

Once you get good at the basics, then you can start adding wet and dry "zing" (spices and liqueurs) to your fruit ingredients and creating your own custom recipes. Or you can learn how to make pectin-free jams. But first, it's helpful to get comfortable with the fundamentals.

There are so many great resources on learning to can out there; get started on learning this important skill this summer! Or take your basic knowledge of canning to a whole new level of experimentation instead by playing around with the more advanced recipes in these books and blogs.

Remember, it's perfectly okay not to be a Canning Diva; you're not a canning failure if you don't spend all your time in the kitchen or put up great quantities of food. Do as much or as little canning as you have time for, but do learn to can so we keep this important skill alive and so that you have shelf-stable food put aside for emergencies. 

Wednesday, June 18, 2014

Breastfeeding And Gestational Diabetes, Part One: Vital Benefits to Mother and Baby

More and more research is showing how important breastfeeding is after a Gestational Diabetes (GD) pregnancy, both for mother and baby.

Yet research consistently also shows lower rates of breastfeeding after Gestational Diabetes.

Promoting and improving breastfeeding rates in GD mothers is one easy way to improve the long-term health of mothers and babies exposed to GD, yet there are still far too many barriers to it.

Let's start with the many benefits of breastfeeding after GD, both for mother and baby.

How Breastfeeding Helps After Gestational Diabetes

Image credit: Much 2014
Breastfeeding improves the mother's blood sugar and insulin levels very quickly post-partum, and improves glucose utilization. It may also improve pancreatic beta cell mass, proliferation, and function, which should improve the mother's capacity to produce insulin adequate to compensate for any insulin resistance.

GD women who breastfeed have lower rates of abnormal blood sugar at their 6-week follow-up glucose tolerance test postpartum.

Breastfeeding also lowers insulin levels and improves insulin sensitivity more long-term.

As a result, breastfeeding lowers a mother's risk for developing diabetes later in life.

Even only a short period of breastfeeding offers some protection. However, the more you breastfeed and the longer the duration, the more your risk for diabetes may be diminished. That's HUGE.

Image credit: Much 2014, adapted from Ziegler 2012
Look at the graph above. Although many women were lost to follow-up, there was a clear and strong trend towards less diabetes in the women who breastfed their babies for more than three months. 72.6% of those who did not breastfeed or who breastfed for three or fewer months developed diabetes by 15 years post-partum, vs. 42% of those who breastfed for more than three months.

And really, three months of breastfeeding isn't that long in the scheme of things. Studies that looked at moderately longer periods found much lower insulin levels and better insulin sensitivity in those that nursed more than 10 months.

And 10 months does not even meet the American Academy of Pediatric's recommendation to nurse at least a year, or the World Health Organization's recommendation to nurse at least two years. How much more protection might there be for longer periods of breastfeeding?

One very large 2005 study found that the risk for diabetes declined about 15% for each additional cumulative year of breastfeeding, and another 2008 study found that the relative risk for diabetes was 0.68 in those with 4 or more years of lifetime lactation duration.

Breastfeeding may also offer some degree of protection against certain types of cancer which GD mothers may be more at risk for, including breast, endometrial, ovarian and possibly pancreatic cancers.

Even more imporantly, long-term breastfeeding may also offer some protection against heart disease and mortality

Some studies have found lower rates of cardiovascular risk factors in women with long-term breastfeeding. Most importantly, research has shown that breastfeeding translates into fewer heart attacks and lower mortality rates too. That's also HUGE.

One theory to explain all this is that pregnancy induces temporary changes in glucose and lipid metabolism that are beneficial for baby but not for the mother, and that these changes are even more marked in women with Gestational Diabetes. In this theory, breastfeeding is nature's way of "re-setting" the mother's metabolism back to normal afterwards. If breastfeeding does not occur (or is brief), the mother's metabolism doesn't really return to normal and she is much more likely to develop diabetes, hypertension, and heart disease with time.

Although this is still just a theory at this point, it is a logical one, and one with some data to support its premise. Obviously, the human body is complex and many different factors play a role in the development of disease, but long-term breastfeeding may be an effective, low-cost, and extremely practical way to lower the risk for later disease.

Clearly, breastfeeding (and especially long-term breastfeeding) has important potential benefits for GD mothers.

Extra Benefits for GD Babies

Breastfeeding has so many benefits for all babies. We've known this for quite a while, yet it's surprising how often this does not get communicated well to pregnant women or the general public.

The general benefits of breastfeeding include lower risk for infections, asthma, diarrhea, ear infections, celiac disease, Sudden Infant Death Syndrome (SIDS)necrotizing enterocolitis in pre-term infants, and many other things. That's all pretty important right there.

But breastfeeding has extremely important immunological functions that are under-appreciated even among care providers. When in utero, the baby depends on the mother's placenta for immunological protection. After the baby is born, its own immunological system is quite immature. Nature designed breastfeeding to help bridge the gap between in utero protection and when the baby's own immunological system matures.

The first milk, colostrum, plays a vital role in "coating" the surface of the baby's intestines to help them be less vulnerable to pathogens. Later, human milk encourages the growth of the villi in the intestine and develops antibody responses specific to the pathogens the mother encounters. It also helps the baby strengthen and develop its own immuno-responses to pathogens, which may provide enhanced immuno-protection even after breastfeeding ends. Thus, breastfeeding is crucial in protecting the baby's immune system both short- and long-term. Its benefits do not end with weaning.

These are all important reasons to raise breastfeeding rates in the general population. However, there are additional potential benefits for babies of GD pregnancies.

The biggest benefit of breastfeeding after a GD pregnancy is that it lowers the risk of the baby developing diabetes as he/she grows to adulthood.

This is another HUGE advantage. Babies exposed to higher blood sugar rates in utero tend to have poorer glucose metabolisms, more insulin resistance, and more metabolic syndrome later in life.

If breastfeeding can prevent or delay many cases of metabolic syndrome and diabetes in a GD mother's offspring, it has tremendous public health implications for babies as well as mothers.

And this may be a particularly important finding for people of color, because of their increased risk for diabetes. One early study in a particularly vulnerable population (Pima Indians) found about half the risk for diabetes in adults who were breastfed for at least two months compared to those who were not. Imagine what the difference might be with longer periods of breastfeeding!

One study projected that if 90% of families in the U.S. breastfed exclusively for 6 months, about 911 deaths would be prevented each year. Of course, data projections like this are merely speculative, but even so, a clear trend in the statistical model implies that increasing breastfeeding rates would be a low-cost, effective strategy for improving public health in babies as well as in mothers.

And this may especially be true for babies of GD pregnancies.


Breastfeeding is a vital part of the so-called "fourth trimester" of pregnancy...and well beyond.

In other words, the mother's biological role in protecting her baby does not end with the baby's birth. It extends into breastfeeding and even beyond weaning.

Nature intended babies to be breastfed for significant periods of time in order to protect them while they are immunologically immature and to produce optimal and healthy growth and development. Nature also intended breastfeeding to benefit the mother by re-setting her metabolism and lowering her risk for heart disease and some cancers. Breastfeeding's benefits to both baby and mother do not end with weaning but appear to last for years afterwards.

Obviously, there are times when breastfeeding isn't possible, doesn't work out, or isn't wanted for various reasons, and it's good that we have substitutes available for these situations. Formula isn't "bad" or "evil," and it's a reasonably good substitute when human breastmilk is not available. Although uncommon, there are women who are truly unable to breastfeed and it's important that we have respect for that experience and support for those women even as we promote breastfeeding.

However, we must remember that Nature's design results in the most optimal outcomes and we subvert that design at the risk of significant harm on a population-wide basis. 

How much of our public health woes today are due to the widespread and very strong discouragement of breastfeeding by physicians in the last century? We may never know, but I would bet that at least some of the increase in diabetes and other problems we see today is at least partly due to the tremendous pressure on women from the mid-20th century not to breastfeed.

Even today, when most care providers at least pay lip service to the benefits of breastfeeding, many women are subtly discouraged from nursing or are told that there is little benefit to continuing to breastfeed past a few months. (Yep, I heard this one).

Even more alarming, despite evidence of EXTRA benefits to breastfeeding after a GD pregnancy, women with Gestational Diabetes have lower rates of breastfeeding than other women. 

Although some of this may have some basis in biological differences like PCOS (Polycystic Ovarian Syndrome), much of it is rooted in routine practices and interventions common during and after births in women with Gestational Diabetes. Yet care providers often fail to recognize that breastfeeding "failure" often begins with the interventions that occur during and after birth. 

There is much that can be done to raise breastfeeding rates in women with GD, if only caregivers and hospitals would recognize the role that common interventions plays in interfering with establishment of breastfeeding.

That's not to say that interventions should never take place. Sometimes interventions are truly necessary, especially in complicated cases of GD, but the reality is that they are often overused, and reducing them is a good first step in increasing breastfeeding rates. And even when interventions are truly necessary, there is much that can be done to protect and promote breastfeeding under less than ideal conditions, yet full implementation of these measures is lacking in many hospitals.

In our next post, we will discuss specifics on how to remove barriers and raise breastfeeding rates in women with GD. For the long-term health of babies and mothers, it is critical that we do this.


Breastfeeding and Short-Term Maternal Glucose Tolerance

Ir Med J. 2012 May;105(5 Suppl):31-6. Breast-feeding is associated with reduced postpartum maternal glucose intolerance after gestational diabetes. O'Reilly M, Avalos G, Dennedy MC, O'Sullivan EP, Dunne FP. PMID: 22838108
...We prospectively examined the prevalence of postpartum dysglycaemia after GDM and examined the effect of lactation on postpartum glucose tolerance. We compared postpartum 75g oral glucose tolerance test (OGTT) results from 300 women with GDM and 220 controls with normal gestational glucose tolerance (NGT). Breast-feeding data was collected at time of OGTT...The prevalence of persistent hyperglycaemia was significantly lower in women who breast-fed versus bottle-fed postpartum (8.2% v 18.4%, p < 0.001). Breast-feeding may confer beneficial metabolic effects after GDM and should be encouraged.
Diabetes Care. 2012 Jan;35(1):50-6. doi: 10.2337/dc11-1409. Epub 2011 Oct 19. Lactation intensity and postpartum maternal glucose tolerance and insulin resistance in women with recent GDM: the SWIFT cohort. Gunderson EP, Hedderson MM, Chiang V, Crites Y, Walton D, Azevedo RA, Fox G, Elmasian C, Young S, Salvador N, Lum M, Quesenberry CP, Lo JC, Sternfeld B,Ferrara A, Selby JV. PMID: 22011407
OBJECTIVE: To examine the association between breastfeeding intensity in relation to maternal blood glucose and insulin and glucose intolerance based on the postpartum 2-h 75-g oral glucose tolerance test (OGTT) results at 6-9 weeks after a pregnancy with gestational diabetes mellitus (GDM). RESEARCH DESIGN AND METHODS: We selected 522 participants enrolled into the Study of Women, Infant Feeding, and Type 2 Diabetes (SWIFT), a prospective observational cohort study of Kaiser Permanente Northern California members...RESULTS:...Exclusive or mostly breastfeeding groups had lower prevalence of diabetes or prediabetes (P = 0.02). CONCLUSIONS: Higher intensity of lactation was associated with improved fasting glucose and lower insulin levels at 6-9 weeks' postpartum. Lactation may have favorable effects on glucose metabolism and insulin sensitivity that may reduce diabetes risk after GDM pregnancy.
Obstet Gynecol. 2012 Jul;120(1):136-43. doi: 10.1097/AOG.0b013e31825b993d. Influence of breastfeeding during the postpartum oral glucose tolerance test on plasma glucose and insulin.
Gunderson EP, Crites Y, Chiang V, Walton D, Azevedo RA, Fox G, Elmasian C, Young S, Salvador N, Lum M, Hedderson MM, Quesenberry CP, Lo JC, Ferrara A,Sternfeld B. PMID: 22914402
...Participants were enrolled in the Study of Women, Infant Feeding, and Type 2 Diabetes, a prospective observational cohort study of 1,035 Kaiser Permanente Northern California members who had been diagnosed with GDM...RESULTS: Of 835 lactating women, 205 (25%) breastfed their infants during the 2-hour 75-g OGTT at 6-9 weeks postpartum....CONCLUSION: Among postpartum women with recent gestational diabetes mellitus, breastfeeding an infant during the 2-hour 75-g OGTT may modestly lower plasma 2-hour glucose (5% lower on average) as well as insulin concentrations in response to ingestion of glucose.
Breastfeeding and Subsequent Maternal Diabetes

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. RESULTS A total of 3,160 (6.0%) women were classified as having type 2 diabetes. Overall, nulliparous and parous women had a similar risk of diabetes. Among parous women, there was a 14% (95% CI 10-18%, P < 0.001) reduced likelihood of diabetes per year of breastfeeding. Compared to nulliparous women, parous women who did not breastfeed had a greater risk of diabetes (odds ratio 1.48, 95% CI 1.26-1.73, P < 0.001), whereas for women breastfeeding, the risk was not significantly increased. 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.
Diabetes. 2012 Dec;61(12):3167-71. doi: 10.2337/db12-0393. Epub 2012 Oct 15. Long-term protective effect of lactation on the development of type 2 diabetes in women with recent gestational diabetes mellitus. Ziegler AG, Wallner M, Kaiser I, Rossbauer M, Harsunen MH, Lachmann L, Maier J, Winkler C, Hummel S. PMID: 23069624
...To investigate whether breastfeeding influences short- and long-term postpartum diabetes outcomes, women with GDM (n = 304) participating in the prospective German GDM study were followed from delivery for up to 19 years postpartum for diabetes development. All participants were recruited between 1989 and 1999. Postpartum diabetes developed in 147 women and was dependent on the treatment received during pregnancy (insulin vs. diet), BMI, and presence/absence of islet autoantibodies. Among islet autoantibody-negative women,breastfeeding was associated with median time to diabetes of 12.3 years compared with 2.3 years in women who did not breastfeed. The lowest postpartum diabetes risk was observed in women who breastfed for >3 months. On the basis of these results, we recommend that breastfeeding should be encouraged among these women because it offers a safe and feasible low-cost intervention to reduce the risk of subsequent diabetes in this high-risk population. 
Lactation Duration and Subsequent Maternal Diabetes

Eur J Endocrinol. 2013 Mar 15;168(4):515-23. doi: 10.1530/EJE-12-0939. Print 2013 Apr. Relationship between lactation duration and insulin and glucose response among women with prior gestational diabetes. Chouinard-Castonguay S, Weisnagel SJ, Tchernof A, Robitaille J. PMID: 23302255
...The study group comprised 144 women with a history of GDM between 2003 and 2010. Plasma insulin and glucose concentrations were obtained from a 75 g oral glucose tolerance test (OGTT). Total lactation duration (exclusive breastfeeding and breast and bottle-feeding) for all infants was self-reported in months. RESULTS: Mean age was 36.5±5.0 years. Time between delivery and metabolic testing was 4.0±1.9 years. Women breastfed for an average of 13.9±16.8 months. Most women (80.6%) reported a history of lactation...Compared with women who lactated for <10 months, women who lactated for ≥10 months had improved insulin sensitivity-secretion index, higher HOMA-IS and Matsuda indices, lower fasting and 2-h post-OGTT insulin concentrations as well as AUC for insulin, and lower incidence of impaired glucose intolerance (P≤0.05 for all). In multiple linear regression analyses, lactation duration emerged as an independent predictor of fasting insulin concentrations (β=-0.02) and insulin sensitivity indices (β=0.02) (P≤0.05 for all). CONCLUSIONS: These results suggest that longer duration of lactation is associated with improved insulin and glucose response among women with prior GDM.
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. Lactation may reduce risk of type 2 diabetes in young and middle-aged women by improving glucose homeostasis. 
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 Implications

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 T1, 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.
Breastfeeding and Maternal Cancer

Am J Clin Nutr. 2013 Oct;98(4):1020-31. doi: 10.3945/ajcn.113.062794. Epub 2013 Aug 21. Breastfeeding and ovarian cancer risk: a meta-analysis of epidemiologic studies. Luan NN1, Wu QJ, Gong TT, Vogtmann E, Wang YL, Lin B. PMID: 23966430
...We performed a meta-analysis to summarize available evidence of the association between breastfeeding and breastfeeding duration and EOC [ovarian cancer] risk from published cohort and case-control studies...RESULTS: Five prospective and 30 case-control studies were included in this analysis. The pooled RR for ever compared with never breastfeeding was 0.76 (95% CI: 0.69, 0.83), with moderate heterogeneity (Q = 69.4, P < 0.001, I(2) = 55.3%). Risk of EOC decreased by 8% for every 5-mo increase in the duration of breastfeeding (RR: 0.92; 95% CI: 0.90, 0.95). The risk reduction was similar for borderline and invasive EOC and was consistent within case-control and cohort studies. CONCLUSIONS: Results of this meta-analysis support the hypothesis that ever breastfeeding and a longer duration of breastfeeding are associated with lower risks of EOC....
Breastfeeding and Diabetes in Children

Am J Clin Nutr. 2006 Nov;84(5):1043-54. Does breastfeeding influence risk of type 2 diabetes in later life? A quantitative analysis of published evidence. Owen CG, Martin RM, Whincup PH, Smith GD, Cook DG. PMID: 17093156
...DESIGN: A systematic review of published studies identified 1010 reports; 23 examined the relation between infant feeding and type 2 diabetes in later life or risk factors for diabetes...RESULTS: Subjects who were breastfed had a lower risk of type 2 diabetes in later life than did those who were formula fed (7 studies; 76 744 subjects; odds ratio: 0.61; 95% CI: 0.44, 0.85; P = 0.003). Children and adults without diabetes who had been breastfed had marginally lower fasting insulin concentrations than did those who were formula fed (6 studies; 4800 subjects; percentage difference: -3%; 95% CI: -8%, 1%; P = 0.13); no significant difference in fasting glucose concentrations was observed...CONCLUSION: Breastfeeding in infancy is associated with a reduced risk of type 2 diabetes, with marginally lower insulin concentrations in later life, and with lower blood glucose and serum insulin concentrations in infancy.
Lower Rates of Breastfeeding in Women with Diabetes

Diabet Med. 2013 Sep;30(9):1094-101. doi: 10.1111/dme.12238. Epub 2013 Jun 21. Breastfeeding in women with diabetes: lower rates despite greater rewards. A population-based study. Finkelstein SA, Keely E, Feig DS, Tu X, Yasseen AS 3rd, Walker M. PMID: 23692476
...METHODS: A retrospective cohort analysis was conducted using data from four Ontario hospitals. Women who delivered a viable infant between 1 April 2008 and 31 March 2010 were included in the study...CONCLUSIONS: Women with insulin-treated diabetes had the poorest outcomes with respect to breastfeeding rates. Gestational and non-insulin-treated diabetes were associated with lower rates of breastfeeding in hospital, while gestational diabetes was additionally associated with lower breastfeeding rates on discharge.
Dtsch Med Wochenschr. 2008 Feb;133(5):180-4. doi: 10.1055/s-2008-1017493. [Breastfeeding in women with gestational diabetes]. Hummel S, Hummel M, Knopff A, Bonifacio E, Ziegler AG. PMID: 18213549
...METHODS: Breastfeeding habits (breastfeeding of any duration) were recorded of 257 mothers with gestational diabetes...who participated in a prospective post-partum study between 1989 and 1999 and compared to breastfeeding habits of 527 healthy mothers... all enrolled in the prospective BABYDIAB study between the years 1989 and 2000...RESULTS: Compared to children of healthy mothers, fewer children of mothers with gestational diabetes were breastfed (75% vs 86%; P<0.0001). Among breastfed children the duration of full or any breastfeeding was shorter in children of mothers with gestational diabetes (median for full breastfeeding 9 weeks. [mothers with gestational diabetes] vs. 17 weeks. [healthy mothers]; p<0.0001; median duration of any breastfeeding 16 weeks. vs. 26 weeks.; p<0.0001)...Full and any breastfeeding was shorter in women with insulin-dependent gestational diabetes than in those with diet-controlled gestational diabetes (full breast-feeding 4 weeks. vs. 12 weeks.; p<0.01 and any breastfeeding 10 weeks. vs. 20 weeks,; p<0.0001)....

Thursday, June 5, 2014

Bonehead Ideas: High Cholesterol Equals High Cesarean Rates in Obese Women

Periodically, the obstetric world comes up with some bizarre theories as to why "obese" women have higher cesarean rates than women of average size.

The reasons behind higher rates is a valid question, but the way in which the obstetric world examines the question reveals much of their biases and assumptions around obesity.

One of their more persistent theories is the "Fat Vagina" theory, where they theorize that the vaginas of high-BMI women are lined with fat pads that will prevent a baby from getting out. Sadly, many doctors and midwives are still taught this theory as if it is established fact, when in truth, there is no data to back it up.

And of course, the current favorite among many providers is the "High Prenatal Weight Gain" theory, where women who gain more than the approved amount of weight are blamed for cesareans. And since any gain at all in obese women is considered "too much" by many providers, this may play a particularly potent role in the cesarean rate in women of size. But providers making a causal connection between high gains and cesareans completely ignore the role that fear and bias around high gains can play in many labors. It may not be high gains per se that cause more cesareans but rather the fears and interventions common in high-gain women (especially "high" gain obese women) that result in more cesareans.

One of the more ludicrous theories that doctors have come up with in recent years to excuse abysmally-high cesarean rates in fat women is the "Cholesterol Inhibits Myometrial Activity" theory.

Sadly, this theory gained a lot of mention in obstetric literature in recent years, despite very limited and dubious evidence to support it.

High Cholesterol Causes Cesareans?

In the Cholesterol Theory, high cesarean rates in fat women are supposedly caused by high cholesterol rates (since, you know, all fat women have high cholesterol) because high cholesterol rates supposedly impair the contractility of the uterine muscle.

Say what? Yeah, I know, that was my reaction too.

But yes, it was an actual theory put forward by a number of researchers in recent years. (And its kissin' cousins, that leptin or some other substance are the guilty parties instead.)

Because, you know, all fat women are defective and this explains how.

So the theory goes, if we give fat pregnant women statin medications, maybe that will cut their cesarean rate. Yes, there are actually doctors who have proposed doing this.

Fortunately, there is a recent study out that casts serious doubt on this bonehead Cholesterol Theory.

Problems with the Cholesterol Theory

I've written about this issue before, pointing out that the Cholesterol Theory has a number of problems.

First of all, many fat women do NOT have high cholesterol at all. (I'm one of them.) Many fat women have perfectly normal cholesterol levels, particularly during childbearing years. The fact that researchers assume that nearly all fat people have high cholesterol is symbolic of the typical assumptions researchers make about fat people and how these impact their ability to reach sound conclusions.

Second, the studies on "poor contractility" in obese women are quite small. This certainly raises the question of how whether the findings could be related to coincidence or confounding factors, rather than showing a true causal relationship. But virtually no one raises this question. They are happy to just jump to conclusions.

Third, please note that many of the studies supposedly showing "poor contractility" in obese women were done on women having planned cesareans with NO labor. How does this prove how they might have labored in real life? They took samples of the uteri before labor even started, and then did some lab tests on them, testing "contractility" in the lab.

Sorry, this is hardly indicative of real-life labor and birth, and since they did pre-emptive cesareans on these women, how can they prove that these in vitro "contractility" tests really have any relationship to how labor would have gone? There is just no way that this proves that there is something wrong with fat women's uteri.

Furthermore, they did not look for any other explanations for lower contractility in vitro. Studies show that fat women tend to have longer menstrual cycles and longer pregnancies. Planned cesareans like these were often done at 38 or 39 weeks, and if obese women tend to go into spontaneous labor closer to 42 weeks (either due to inaccurate dating from longer cycles or because of a tendency towards longer pregnancies), doing such an early cesarean would not reliably show whether their uteri were inherently "less contractile." Rather, it would simply suggest that these obese women were not even close to spontaneous labor yet and therefore less responsive to stimulants.

The bottom line is that these studies have a lot of issues.

While it's not wrong to propose a hypothesis for an observed problem, you have to be careful about jumping to conclusions too quickly. These studies relied on very small sample sizes, speculated about an obese woman's response to labor based on in vitro testing from a pre-labor cesarean, didn't explore alternate causes for the findings, and generalized assumptions about obesity and cholesterol levels in a very broad and questionable manner.

The Cholesterol Theory is FAR from a proven connection, although you'd never know it, based on the way many researchers discuss it. And the research certainly does not support routinely putting fat women on statin medications.

The Newest Study on Cholesterol and Cesareans

My biggest question last time I wrote about this issue was whether they had done any studies to see if the fat women who delivered vaginally had better cholesterol levels than the ones who had cesareans, or whether thin women with high cholesterol had more cesareans.

Well, finally we have a study directly addressing some of this. A recent study from New Zealand compared delivery method (cesarean vs. vaginal birth) with women's cholesterol levels at 14-16 weeks to see if there was a correlation between high cholesterol and cesareans.

They found there was NO correlation between the mother's cholesterol levels in early pregnancy and her delivery method. 

However, surprise surprise, they found that induction of labor was connected to cesareans. Imagine!

They concluded:
Elevated maternal cholesterol in early pregnancy is not a risk factor for first stage caesarean for failure to progress in overweight/obese women. 

This "High Cholesterol Causes Cesareans in Obese Women" theory is the kind of bad science that makes fat people so distrustful of medicine and doctors.

So often, it's all just based on ASSUMPTIONS about fat people and not on any real detailed study or logical questioning of theories.

Furthermore, the fact that several years ago they publicized this theory without having proven it and were even marketing the idea of giving statins was absolutely irresponsible.

Statins are CONTRAINDICATED in pregnancy; they are category "X" and may cause birth defects. Cholesterol and lipids play a very important role in fetal development. There is a reason why a pregnant woman's cholesterol rises during pregnancy; the baby needs it for development. Artificially lowering these levels may have devastating effects on the baby.

Critics responded that they were "only" suggesting putting fat women on statins in the last few months of pregnancy, so therefore there would be no risk of birth defects. But if these drugs can be so dangerous in early pregnancy, who knows what kind of harm they might cause late in pregnancy as well? There are other harms that can be caused to babies besides birth defects during organogenesis.

No one knows for sure what critical roles cholesterol and lipids play during late pregnancy. Pregnant women's cholesterol levels rise through pregnancy, suggesting that it has an important biological role to play in the end of pregnancy. Putting women on statins at the end of pregnancy may be just as harmful as at the beginning of pregnancy, just perhaps with more subtle problems than birth defects.

What it boils down to is that they were proposing using fat women's babies as lab rats to experiment on, based on extremely flimsy theories. This is UNACCEPTABLE.

There is completely insufficient evidence to support the idea that high cholesterol is the cause of the high cesarean rate in fat women, and the safety of statins in pregnancy at ANY stage is highly questionable. To suggest treatment with statins for anyone during any stage of pregnancy is risky and BAD science.

Furthermore, to be running stories in the media suggesting statin use in fat pregnant women before suitable research was done substantiating the Cholesterol Theory was reprehensible. It smacks of a few researchers looking for a "hook" to gain name recognition and funding (or a drug company looking for new revenue streams), rather than serious and responsible scientists pursuing a legitimate investigation.

You can read more about the original story here.

It is time for researchers to stop jumping to conclusions about fat women and pregnancy, time for them to examine their own faulty assumptions about obesity and how this distorts their research, time for them to stop using fat women's babies as lab rats for their own personal theories, and time for researchers to stop prematurely "spinning" preliminary research in order to get name recognition and research funding.

It's far too easy for care providers to blame the high cesarean rate in obese women on Fat Vaginas, High Cholesterol, High Prenatal Weight Gain or whatever other boogeyman is currently popular in the obstetric literature. This blames the victim and conveniently absolves themselves of blame.

It is long past time for obstetric researchers to stop blaming women and do the uncomfortable job of examining how their own practices and biases raise the cesarean rate in obese women.


BMC Pregnancy Childbirth. 2013 Jul 9;13:143. doi: 10.1186/1471-2393-13-143. Elevated maternal lipids in early pregnancy are not associated with risk of intrapartum caesarean in overweight and obese nulliparous women. Fyfe EM, Rivers KS, Thompson JM, Thiyagarajan KP, Groom KM, Dekker GA, McCowan LM; SCOPE consortium. PMID: 23835080 Full text available here.
BACKGROUND: Maternal overweight and obesity are associated with slower labour progress and increased caesarean delivery for failure to progress. Obesity is also associated with hyperlipidaemia and cholesterol inhibits myometrial contractility in vitro. Our aim was, among overweight and obese nulliparous women, to investigate 1. the role of early pregnancy serum cholesterol and 2. clinical risk factors associated with first stage caesarean for failure to progress at term. METHODS: Secondary data analysis from a prospective cohort of overweight/obese New Zealand and Australian nullipara recruited to the SCOPE study. Women who laboured at term and delivered vaginally (n=840) or required first stage caesarean for failure to progress (n=196) were included. Maternal characteristics and serum cholesterol at 14-16 weeks' of gestation were compared according to delivery mode in univariable and multivariable analyses (adjusted for BMI, maternal age and height, obstetric care type, induction of labour and gestation at delivery ≥41 weeks). RESULTS: Total cholesterol at 14-16 weeks was not higher among women requiring first stage caesarean for failure to progress compared to those with vaginal delivery (5.55 ± 0.92 versus 5.67 ± 0.85 mmol/L, p= 0.10 respectively). Antenatal risk factors for first stage caesarean for failure to progress in overweight and obese women were BMI (adjusted odds ratio [aOR (95% CI)] 1.15 (1.07-1.22) per 5 unit increase, maternal age 1.37 (1.17-1.61) per 5 year increase, height 1.09 (1.06-1.12) per 1cm reduction), induction of labour 1.94 (1.38-2.73) and prolonged pregnancy ≥41 weeks 1.64 (1.14-2.35). CONCLUSIONS: Elevated maternal cholesterol in early pregnancy is not a risk factor for first stage caesarean for failure to progress in overweight/obese women. Other clinically relevant risk factors identified are: increasing maternal BMI, increasing maternal age, induction of labour and prolonged pregnancy ≥41 weeks' of gestation.
Theories on Cholesterol, Leptin, and Myometrial Contractility

Med Hypotheses. 2011 May;76(5):755-60. doi: 10.1016/j.mehy.2011.02.018. Epub 2011 Mar 5. Proposed biological linkages between obesity, stress, and inefficient uterine contractility during labor in humans. Lowe NK, Corwin EJ. PMID: 21382668
Cesarean delivery has reached epidemic proportions in contemporary western healthcare. For otherwise healthy first-time (nulliparous) women at term gestation with a single fetus in a head down position, the most common clinical diagnosis prompting cesarean delivery is dystocia, including clinical terms such as uterine dysfunction, failure to progress, arrest of dilation and/or arrest of descent of the fetal head. In 2006, the cesarean rate for this lowest risk population of childbearing women was 26% in the United States despite the goal of Healthy People 2010 to reduce this rate to 15% from a baseline of 18% in 1998. While multiple lines of evidence suggest that the nulliparous uterus is particularly vulnerable to a diagnosis of uterine dysfunction during labor, pathophysiologic explanations for this dysfunction have not been well described. The acute stress response has been implicated as one factor in this dysfunction for many years, while more recently the growing epidemic of adiposity among women of childbearing age has been suggested as an additional pathway by which myometrial cell function may be disrupted. Using both clinical and in vitro evidence, we hypothesize a combined model in which pathways of acute stress and changes associated with maternal adiposity, particularly exaggerated levels of cholesterol and leptin, may independently and synergistically impair the contractile apparatus of the myocyte leading to the clinical diagnosis of uterine dystocia and subsequent cesarean delivery.
Am J Obstet Gynecol. 2006 Aug;195(2):504-9. Epub 2006 May 2. Inhibitory effect of leptin on human uterine contractility in vitro. Moynihan AT, Hehir MP, Glavey SV, Smith TJ, Morrison JJ. PMID: 16647683
OBJECTIVE: The purpose of this study was to investigate the effects of leptin on human uterine contractility in vitro. STUDY DESIGN: Biopsies of human myometrium were obtained at elective cesarean section (n = 18). Dissected myometrial strips suspended under isometric conditions, undergoing spontaneous and oxytocin-induced contractions, were exposed to cumulative additions of leptin in the concentration range of 1 nmol/L to 1 micromol/L. Control strips were run simultaneously...RESULTS: Leptin exerted a potent and cumulative inhibitory effect on spontaneous and oxytocin-induced contractions compared to control strips...There was an apparent reduction in both frequency and amplitude of contractions. CONCLUSION: This physiologic inhibitory effect of leptin on uterine contractility may play a role in the dysfunctional labor process associated with maternal obesity, and the resultant high cesarean section rates.
Reprod Sci. 2007 Jul;14(5):456-66. Contractility and calcium signaling of human myometrium are profoundly affected by cholesterol manipulation: implications for labor? Jie Zhang, Kendrick A, Quenby S, Wray S. PMID: 17913965
The authors elucidate cholesterol's effect on human uterine contractility and calcium signaling to test the hypotheses that elevation of cholesterol decreases uterine activity and that oxytocin cannot augment contraction when cholesterol is elevated...Elevated cholesterol is deleterious to contractility and Ca2+ signaling in human myometrium. Cholesterol may contribute to uterine quiescence but could cause difficulties in labor in obese/dyslipidemic women, consistent with their increased cesarean delivery rates.
Obesity and Contractility

BJOG. 2007 Mar;114(3):343-8. Epub 2007 Jan 22. Poor uterine contractility in obese women.
Zhang J, Bricker L, Wray S, Quenby S. PMID: 17261121
OBJECTIVE: The aim of the study was to elucidate the reason for the high rate of caesarean section in obese women. We examined the following hypotheses: (1) obese women have a high incidence of complications related to poor uterine contractility--caesarean section for dysfunctional labour and postpartum haemorrhage. 2) The myometrium from obese women has less ability to contract in vitro. DESIGN: First, a clinical retrospective analysis of data from 3913 completed singleton pregnancies was performed. Secondly, in a prospective study the force, frequency and intracellular [Ca(2+)] flux of spontaneously contracting myometrium were related to the maternal body mass index. SETTING: Liverpool Women's Hospital and University of Liverpool. POPULATION: The clinical study involved all women who delivered in one hospital in 2002. The in vitro study myometrial biopsies were obtained from 73 women who had elective caesarean section at term. RESULTS: Maternal obesity carried significant risk of caesarean section in labour that was highest for delay in the first stage of labour (OR 3.54). The increased risk of caesarean section in obese women largely occurred in women with normal- and not with high-birthweight infants. Obese women delivering vaginally had increased risk of prolonged first stage of labour and excessive blood loss. Myometrium from obese women contracted with less force and frequency and had less [Ca(2+)] flux than that from normal-weight women. CONCLUSIONS: We suggest that these findings indicate that obesity may impair the ability of the uterus to contract in labour.