Weight gain in adolescents during pregnancy: rate related to birth-weight outcome.

This study of 459 subjects from prenatal clinics for teenagers at three universities across the United States, addresses questions about gestational weight gain in adolescents raised by the 1990 Institute of Medicine Report. Rate and pattern of gain, independent of pregravid weight, are based on serial measures of mothers with favorable and unfavorable outcomes. Rate of gain (determined by using regression statistics) from weeks 15 to 40 was 0.588, 0.510, and 0.488 kg/wk for mothers of term infants weighing 3000-4000 g, term infants weighing < 3000 g, and preterm infants, respectively. The significantly lower percentage of infants weighing 3000-4000 g vs < 3000 g needing intensive care at birth (6% vs 15%, respectively, P < 0.05) further indicates the superior outcome among mothers with higher rates of gain. Rate of gain of mothers of infants weighing 3000-4000 g (favorable outcome) equaled the highest amount provisionally recommended, suggesting that restricting natural gain of adolescents to recommended rates may result in smaller than optimal infants.