Last year the Institute of Medicine (IOM) revised their guidelines on weight gain in pregnancy.
The new recommendations state that obese women should gain between 11 and 20lbs during pregnancy (compared with a previous recommendation of 15lbs).
The Institute didn't stratify these recommendations to different classes of obesity and consequently whether you've got a BMI of 30 or a BMI of 45 the recommendations remain the same.
Many physicians (myself included) found this to be odd - both in terms of not stratifying recommendations for different obesity classifications and also for recommending any weight gain at all for women with moderate to severe obesity and this week a few like minded physicians took the IOM to task in an article published in the January issue of Obstetrics and Gynecology.
The issues of course are the risks for both mother and baby associated with maternal prenatal obesity. The authors suggest that weight gain during pregnancy and that gain's effect on subsequent weight gain in life (not losing post pregnancy),
"are causes of a permanent increase in weight for every BMI category and are significant contributors to the obesity epidemic and associated comorbidities"They believe that the recommendations are skewed towards the theoretical health of the fetus only and fail to factor in weight gain's risks to the mother which include higher likelihoods of gestational diabetes, hypertension, operative deliveries, pre-eclampsia and neonatal complications which of course in turn put the fetus at risk.
The authors recommend that diet should be tailored for women of different classes of obesity resulting in gestational weight gains of 10lbs or less and in some, weight loss.
I couldn't agree more and while my sincere belief is that 1,500-2,000 calorie diets are sufficient to nourish a fetus and to effect in weight losses for pregnant women with class II and III obesity, thankfully there are studies underway to test that very hypothesis. Belief is a bad way to practice medicine.
Artal R, Lockwood CJ, & Brown HL (2010). Weight gain recommendations in pregnancy and the obesity epidemic. Obstetrics and gynecology, 115 (1), 152-5 PMID: 20027048