Wednesday, January 13, 2010

Obesity, weight gain and pregnancy. Are the guidelines flawed?

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

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  1. My mother gained 40 pounds in each of her two pregnancies (back in the 1970s when breastfeeding was not encouraged) that she never lost, even with several attempts over the years. Her doctor put her on a "low calorie" diet with her first child, but the alarming weight gain (she was 5 ft 2 in tall) continued. Her doctor told her to do (exercise-wise) what she felt like doing, and she felt like sleeping. We were fortunately born without complications. She is now handicapped with severe osteoarthritis. I wish she had access at that time to a good dietician familiar with her physical type (her side of the family is short and round), and a doctor like you. Her subsequent life of ever-increasing pain could have been quite different.

  2. Thank you for posting this. I am a pregnant obese woman and after initially gaining a few pounds in my first trimester, I am currently (20 weeks) half a pound lighter than my pre pregnancy weight. I had been getting concerned at the lack of weight gain at the half way point, because of course all the books say I should be gaining 15 to 20 pounds. Thank you for easing my mind.