Excessive weight gain during pregnancy is a risk factor for postpartum weight retention and future weight gain and obesity. Whether a behavioral intervention in pregnancy can reduce long-term weight retention is unknown.

This randomized trial tested whether a low-intensity behavioral intervention to prevent excessive gestational weight gain could increase the proportion of women who returned to prepregnancy weight by 12 mo postpartum.

Women (n = 401, 13.5 wk of gestation, 50% normal weight, 50% overweight/obese) were randomly assigned into an intervention or control group; 79% completed the 12-mo assessment. The telephone-based intervention targeted gestational weight gain, healthy eating, and exercise and was discontinued at delivery.

In modified intent-to-treat analyses that excluded women with miscarriages (n = 6), gestational diabetes (n = 32), or subsequent pregnancies (n = 32), the intervention had no significant effect on the odds of achieving prepregnancy weight at 12 mo postpartum (n = 331; 35.4% compared with 28.1%; P = 0.18). Completer analyses suggested that the intervention tended to increase the percentages of women who reached prepregnancy weight (n = 261; 45.3% compared with 35.3%; P = 0.09) and significantly reduced the magnitude of mean ± SD postpartum weight retained (1.4 ± 6.3 compared with 3.0 ± 5.7 kg; P = 0.046) at 12 mo. Women in the intervention group reported higher dietary restraint through 6 mo postpartum (P = 0.023) and more frequent self-monitoring of body weight (P < 0.02 for all) throughout the study.

A low-intensity behavioral intervention in pregnancy can reduce 12-mo postpartum weight retention and improve dietary restraint and self-weighing in study completers. Future research is needed to test the long-term effects of more intensive behavioral interventions in pregnancy. This trial was registered at clinicaltrials.gov as NCT01117961.