MATERNAL WEIGHT-GAIN PATTERN AND BIRTH-WEIGHT

Objectives: To determine the relationship between maternal weight gain pattern and birth weight. Methods: All nonobese, white women delivere d at the University of California, San Francisco, between 1980-1990 we re eligible for this study. Our study group included 2994 uncomplicate d pregnancies with complete data. All recorded prenatal weight gain me asurements were used to estimate maternal trimester weight gain, patte rn of gain (based on low versus not-low gain at each trimester), and t otal gain at delivery. Multiple linear regression analysis was used to assess the relationship between these weight gain measurements and fe tal birth weight. Results: After adjustment for seven covariates, each kilogram of maternal gain in the first, second, and third trimesters was associated with statistically significant increases in fetal birth weight of 18.0, 32.8, and 17.0 g, respectively. When compared with th e pattern of gain that was not low in any trimester, patterns with low gain in the first and second trimesters or in the second and third tr imesters were associated with significant decreases in birth weights o f 133.0 and 88.5 g, but no important change in birth weight was seen f or the group whose gains were low in the first and third trimesters. T hese findings were not due to differences in total weight gain, which averaged approximately 11 kg in these three pattern groups. Conclusion : The results suggest that specific patterns of maternal weight gain, particularly weight gain during the second trimester, are related to f etal birth weight.