I have often blogged about the impact of excess weight in pregnancy on both the health of the mother and the infant.

The need to manage gestational diabetes, a frequent complication in overweight and obese women, is well established but the evidence for mild cases is less clear.

This question was now addressed by Mark Landon and colleagues on behalf of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network in a paper just published in the New England Journal of Medicine.

This multicenter trial randomised a total of 958 women who were in the 24th to 31st week of gestation and who met the criteria for mild gestational diabetes mellitus (i.e., an abnormal result on an oral glucose-tolerance test but a fasting glucose level below 95 mg per deciliter [5.3 mmol per liter]) to usual prenatal care (control group) or dietary intervention, self-monitoring of blood glucose, and insulin therapy, if necessary (treatment group).

Although there were no significant differences in the primary outcome consisting of a composite of stillbirth or perinatal death and neonatal complications, including hyperbilirubinemia, hypoglycemia, hyperinsulinemia, and birth trauma, there were significant reductions with treatment as compared with usual care in several prespecified secondary outcomes, including mean birth weight (3302 vs. 3408 g), neonatal fat mass (427 vs. 464 g), the frequency of large-for-gestational-age infants (7.1% vs. 14.5%), birth weight greater than 4000 g (5.9% vs. 14.3%), shoulder dystocia (1.5% vs. 4.0%), and cesarean delivery (26.9% vs. 33.8%).

Interestingly, while the intervention group only gained 2.8 Kg during the pregnancy, the control group gained 5 Kg.

Treatment of mild gestational diabetes mellitus also reduced the rates of preeclampsia and gestational hypertension (combined rates for the two conditions, 8.6% vs. 13.6%; P=0.01).

The authors conclude that although treatment of mild gestational diabetes mellitus may not significantly reduce the frequency of stillbirth, perinatal death and several neonatal complications, it does reduce the risks of fetal overgrowth, shoulder dystocia, cesarean delivery, and hypertensive disorders.

Obviously, the findings cannot be attributed to the effects of the intervention on weight alone, however, they do support the notion that limiting weight gain during pregnancy in overweight and obese women, may be beneficial for both mother and child.

AMS
Edmonton, Alberta.

Regular readers of these pages are aware of my concerns about how excess weight gain in pregnancy can adversely affect both mother and infant (click here for previous posts on this).

This issue is now addressed in a comprehensive new guideline from the Institute of Medicine that reexamines this issue (click here for summary of guideline). This guideline follows on the heels of previous recommendation from the American Dietetic Association and the American Society for Nutrition, published last year.

The report not only sets new levels for weight gain in pregnancy, but also addresses the issue of preconceptual weight given that one of the most important modifiers of pregnancy weight gain and its impact on a mother’s and her baby’s health is a woman’s weight at the start of pregnancy.

The two major differences to previous guidelines are: firstly, the recommendations are now based on the WHO BMI categories rather than the now obsolete Metropolitan Life Insurance tables. Second, the new guidelines include a specific and relatively narrow range of recommended gain for obese women.

It will remain to be seen how successfully these recommendation will be translated into practice.

AMS
Montreal, Quebec

As blogged before, both prepregnancy overweight and excessive weight gain during pregnancy can have significant health impacts on mother and child.

As many readers of these pages may know, there is also an accumulating body of evidence suggesting that intrauterine and early post-partum epigenetic programming may play an important role in promoting and perpetuating the current epidemic of childhood obesity.

It is therefore of interest that this week, the American Dietetic Association and the American Society for Nutrition released new guidelines on addressing excess weight before and during pregnancy.

While there is nothing really novel in the advise given to prospective mothers, the fact that prevention and management of excess weight before and during pregnancy now deserves its own guidelines, is clearly a sign of the increasing recognition of this important issue.

Clearly, the widespread notion of “eating for two” is more than obsolete!

AMS
Edmonton, Alberta

Today I am presenting a talk on obesity at the 54th Annual Meeting of the Canadian Fertility and Andrology Society, being held in Calgary, Alberta. The reason that I’ve been invited, is because, as many of you know, excess weight has a significant negative effect on fertility rates. Indeed, obesity may today be by far the most frequent cause of failure to conceive.

While my talk is on the general approach to obesity diagnosis and management, it is timely that in this week’s issue of JAMA, Melinda Maggard et al. from the University of California, Los Angeles, CA, publish a systematic review on pregnancy and fertility following bariatric surgery.

For their review, Maggard and colleagues searched the Nationwide Inpatient Sample (1998-2005) and multiple electronic databases to identify articles published between 1985 and February 2008 on bariatric surgery among women of reproductive age. Of 260 screened articles, 75 were included. Women aged 18 to 45 years accounted for 49% of all patients undergoing bariatric surgery (>50,000 cases annually for the 3 most recent years).

Matched cohort studies showed lower maternal complication rates after bariatric surgery than in obese women without bariatric surgery, or rates approaching those of nonobese controls. Rates of gestational diabetes (0% vs 22.1%, P < .05) and preeclampsia (0% vs 3.1%, P < .05) were lower in the bariatric surgery patients. These findings were supported by 13 other bariatric cohort studies.

Neonatal outcomes were similar or better after surgery compared with obese women without laparoscopic adjustable gastric band surgery (7.7% vs 7.1% for premature delivery; 7.7% vs 10.6% for low birth weight, P < .05; 7.7% vs 14.6% for macrosomia, P < .05).

Unfortunately, studies regarding nutrition, fertility, cesarean delivery, and contraception were limited.

For e.g. on the issue of fertility, the authors identified 6 studies generally showing improved fertility, although due to lack of a denominator (the number of women actually trying to get pregnant), the impact of surgery is hard to determine. Nevertheless, data clearly shows improvements to complete disappearance of polycystic syndrome and normalization of hormonal patterns and return of normal menstrual cycles.

On the issue of contraception there are isolated reports of failure of contraception following bypass surgery - systematic or controlled trial are lacking.

In summary, the authors concluded that the rates of many adverse maternal and neonatal outcomes may be lower in women who become pregnant after having had bariatric surgery compared with rates in pregnant women who are obese; however, as almost always in this rapidly evolving field of medicine, further data are needed from rigorously designed studies.

Clearly, the good news is that bariatric surgery is not a barrier to having healthy babies - babies, which, as we know from other studies, may in fact have a far lower risk for future obesity, than babies from severely obese mothers, who have not undergone bariatric surgery before pregnancy.

AMS
Edmonton, Alberta

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I’ve previously blogged on the importance of both pre-gestational weight and on excessive gestational weight gain for negative outcomes in mother and child. I’ve also argued that targeting weight in pregnancy may be a “root-cause” solution to the childhood obesity epidemic (i.e. if the findings on intrauterine and perinatal epigenetic programing in animal studies hold true for humans).

But this may be easier said than done. Reason for concern on this approach comes from a recent study by Sunni Mumford and colleagues, from the University of North Carolina at Chapel Hill, published in the Journal of the American Dietetic Association.

Mumford and colleagues assessed dieting practices among a prospective cohort of 1,223 pregnant women. Women were classified on three separate subscales as restrained eaters, dieters, and weight cyclers.

Restrained eating behaviors were associated with weight gains above the Institute of Medicine’s recommendations for normal, overweight, and obese women, and weight gains below the recommendations for underweight women (The Institute of Medicine suggests that women should gain 28 to 40 lbs, 25 to 35 lbs, 15 to 25 lbs and at least 15 lbs for underweight, normal weight, overweight and obese women, respectively). 

Furthermore, women classified as cyclers gained an average of 2 kg more than noncyclers and showed higher observed/expected ratios by 0.2 units.

This obviously has important consequences for counseling women planning to have children. If pre-gestational maternal weight is important and women with overweight and obesity should be counseled to manage their weights prior to pregnancy, dietary restraint may not be the best strategy. In fact, as outlined by Blake Woodside, Director of the Toronto General Eating Disorder Program, at a symposium I spoke at last Friday in Toronto, dieting and restraint are a sure-fire recipe for promoting binging behaviour and setting yourself up for weight gain. 

So “yes”, pre-gestational weight is important, but “no”, dietary restraint is not the answer.

AMS 
Edmonton, Alberta