Gestational weight gain, pregnancy outcome, and postpartum weight retention

To determine whether the risk of maternal overweight associated with an excessive rate of gestational gain needs to be balanced against the risks of impaired fetal growth associated with a low rate of gain.

Rate of gestational weight gain was measured prospectively in a sample of 274 young, low-income, and primarily minority women (12-29 years old) with pregravid body mass indices (BMI) in the normal range (19.8-26.0). We defined an excessive rate of gain between 20-36 weeks' gestation as one greater than 0.68 kg/week, and a low rate of gain as one less than 0.34 kg/week. Women were followed-up at 4-6 weeks and 6 months postpartum.

Rate of measured gestational gain between 20-36 weeks' gestation was associated with total weight gain based on pregravid weight, with infant birth weight and gestation duration, and with maternal overweight (BMI greater than 26) and weight retention postpartum. Infant birth weight and gestation duration were significantly reduced for women with low rates of gain, and there was no significant difference between women with excessive and moderate gains. Despite little difference in pregravid BMI, women with excessive rates of gain retained more weight overall, attained a greater postpartum BMI, and had higher levels of subcutaneous fat and overweight. Maternal anthropometric status showed little change between 4-6 weeks and 6 months postpartum.

Weight gained at an excessive rate by women with a pregravid BMI in the normal range does not greatly enhance fetal growth and gestation duration, contributing instead to postpartum maternal overweight.