Randomized controlled trial to prevent excessive weight gain in pregnant women

Background: The Institute of Medicine (IOM) recommends that normal-weight women (BMI (body mass index) of 19.8-26.0) gain 25-35 lb (11.4-15.9 kg) during pregnancy, and that overweight women (BMI of 26.1-29.0) gain 15-25 lbs (6.8-11.4 kg). A significant number of normal-weight women and an even greater proportion of overweight women exceed these guidelines, which increases postpartum weight retention and may contribute to the development of obesity.

Objective: To determine whether a stepped care, behavioral intervention will decrease the percentage of women who gain more than the IOM recommendation.

Design: Randomized controlled trial comparing a stepped-care behavioral intervention with usual care. Women (n=120) who had a BMI>19.8, age>18 and <20 weeks gestation were recruited from a hospital-based clinic serving low-income women and randomized by race and BMI category to the intervention or control group. The intervention group received education about weight gain, healthy eating, and exercise and individual graphs of their weight gain. Those exceeding weight gain goals were given more intensive intervention. Women were followed through pregnancy to their first postpartum clinic visit. The main outcome measure was weight gain during pregnancy categorized as above the IOM recommendations vs below or within the IOM recommendations.

Results: The intervention significantly decreased the percentage of normal-weight women who exceeded the IOM recommendations (33 vs 58%, P<0.05). There was a non-significant (P=0.09) effect in the opposite direction among overweight women (59% of intervention and 32% of control gained more than recommended). Postpartum weight retention was strongly related to weight gain during pregnancy (r=0.89).

Conclusions: The intervention reduced excessive weight gain during pregnancy among normal weight women.