TIMING OF WEIGHT-GAIN DURING PREGNANCY - PROMOTING FETAL GROWTH AND MINIMIZING MATERNAL WEIGHT RETENTION

OBJECTIVE: To examine the association of the extent and timing of preg nancy weight gain with infant birth weight (IBW) and postpartum weight retention (PPWR). DESIGN: Retrospective cohort study of pregnant wome n followed through 6 weeks postpartum. MEASUREMENTS: Birth weight and maternal weight gain before 20 weeks, 21-30 weeks, 31 weeks to term an d postpartum weight retention were measured. SUBJECTS: A total of 371 healthy white nonsmoking pregnant women followed by the Prenatal Nutri tion Counselling Program of the Department of Health and Social Servic es of the province of Prince Edward Island, Canada, between 1979 and 1 989 who had uncomplicated pregnancies resulting in full term singleton infants. RESULTS: Weight gain during pregnancy (>12 kg) was associate d with PPWR (>2.5 kg) in underweight normal and overweight women. Preg nancy weight gain explained 65.2% of the variability in PPWR, but very little of the variability (4.7%) in IBW. Predictors of IBW (gestation al age, pregravid weight and infant gender) were not related to PPWR. Early maternal weight gain (less than or equal to 20 weeks) was a stro ng predictor of PPWR. Comparisons of mothers with PPWR above and below the median of the group indicated important differences in early weig ht gain (less than or equal to 20 weeks) for underweight (3.3 kg), nor mal weight (3.3 kg), and overweight (6.2 kg) mothers. CONCLUSION: The results emphasize the importance of the timing of gestational weight g ain and show an advantage in deferring a larger portion of required we ight gain to late pregnancy (particularly in well-nourished overweight women) in order to promote fetal growth while reducing the risk of hi gh weight retention and its potential adverse health consequences.