Metformin for Obese Pregnant Women Did Not Prevent Fetal Macrosomia

The far-reaching consequences of the obesity epidemic include increased risk for adverse maternal and neonatal outcomes in pregnancy. As strategies focusing on diet and exercise have not proven effective, interest has turned to pharmacologic interventions. British investigators randomized 450 women with body-mass index >35 kg/m² but without overt diabetes to receive either metformin in escalated doses or placebo beginning at 12 to 18 weeks' gestation.

Infants of women who received metformin had no reduction in median birth weight (the primary outcome) compared with those in the placebo group. However, women in the metformin group had less gestational weight gain (4.6 vs. 6.3 kg, P<0.001) and substantially lower rates of preeclampsia (3% vs. …