Different weight gain in women of normal weight before pregnancy: Postpartum weight and birth weight

Objective: To identify the effect of different gestational weight gains among women of normal weight before pregnancy on babies' birth weights, and women's weights 18-24 months postpartum. Methods: Two groups of women of normal weight before pregnancy (body mass index [BMI] 19.6-25.4 kg/m(2)) took part in the study (n = 200). They gained either moderate weight (9-15 kg) or high weight (18-24 kg) during pregnancy. From maternity records and telephone interviews, information on age, height, prepregnancy and postpartum weight, gestational weight gain, babies' birth weights, lactation, parity, and smoking habits was collected. Results: High maternal weight gain during pregnancy resulted in mean birth weight 286 g higher than that of babies of mothers who gained moderate weight. The correlation coefficient between birth weight and gestational weight gain was 0.3 (P < .001). The postpartum weight of women with high weight gain during pregnancy was 2.6 +/- 0.38 kg (mean +/- standard error of the mean [SEM]) more than before pregnancy but the group of moderate weight gain weighed 0.1 +/- 0.47 kg less than before pregnancy (P < .001). However, most women in both groups (88.6%) regained normal weight, and prepregnant weight correlated strongly with the weight 18-24 months postpartum (r = 0.79, P < .001). There was not a significant correlation between the duration of lactation and postpartum weight loss (r = 0.04, P > .05). Conclusion: High gestational weight gain among women of normal weight before pregnancy increases birth weight and women's weight postpartum, compared with moderate weight gain. Prepregnant weight is more indicative of post-partum weight, and women reach normal weight again irrespective of gestational weight gain. (Obstet Gynecol 1998;92:377-83. (C) 1998 by The American College of Obstetricians and Gynecologists.).