Proportional weight gain and complications of pregnancy, labor, and delivery in healthy women of normal prepregnant stature.

Detailed reproductive information was obtained through interview at early prenatal visits to hospital clinics, private medical groups, or health maintenance organizations for 4186 women delivered at Yale-New Haven Hospital. From these women, 1,396 were selected who had no preexisting chronic disease, were within their normal prepregnant weight for height as determined by Quetelet's Index (weight2/height2), and were delivered of single infants with no major congenital malformations between 37 and 42 weeks. These women were divided into four quartiles according to their proportional weight gain (weight gain/prepregnant weight): quartile 1 = gains less than or equal to 15%; quartile 2 = gains 16% to 25%; quartile 3 = gains 26% to 35%; quartile 4 = gains greater than 35%. Complications of pregnancy, labor, and delivery were recorded within 2 days of delivery. Compared with the women in quartile 2 those in quartile 4 were 3.8 times more likely to develop gestational hypertension and had a fourfold risk of becoming preeclamptic. They were also significantly more likely to require cesarean section. The size of the infant was a significant risk factor for prolonged second stage of labor in primigravid women (greater than 2 hours) but not in multigravid women (greater than 1 hour). Weight gains of more than 35% almost doubled the risk of a prolonged second stage of labor for multigravid women. High proportional gains were not associated with adverse neonatal outcomes. Clinicians should consider proportional weight gain when advising healthy women about weight gain during pregnancy.