PATTERNS OF MATERNAL WEIGHT-GAIN IN PREGNANCY

A retrospective study of 1145 pregnant women showed that trends in mean maternal weight gain from the time of booking until delivery were not linear. Statistically significant lower rates of maternal weight gain were seen before 16 weeks, after 36 weeks and between 28 and 32 weeks gestation (P < 0.05). The mean maternal weight gain was 10.71 kg (SD 4.3) and the mean weekly weight gain was 0.38 kg (SD 0.16). A wide variation of maternal weight gain was seen in women with a normal outcome. The mean weight gain in heavy (> 68 kg) and light (< 55.4 kg) women was less than that in women whose weight was in the third quartile (60-68 kg, P < 0.05). The mean maternal weight gain was less in young (< 20 years) women than in older women (> 25 years; P < 0.05), less in parous than in primigravid women from week 37 onwards (P < 0.05), less in smokers than in non-smokers from 20 weeks onwards (P < 0.05), and greater in hypertensive women (BP > 140/90) than in normotensive women (P < 0.05) from week 24 onwards. The mean weight gain in women who had small for gestational age (SGA) infants was not significantly different from that in women who had infants that were of appropriate size for gestational age. After taking into account infant and placental weight using multiple regression analysis, the factors that were associated with statistically significant differences in average weekly weight gain were parity, body mass index, smoking habit and raised blood pressure. Only 9.6% of the variation in average weekly weight gain could be predicted using these variables. It is unlikely that the measurement of maternal weight gain would be useful in detecting women who will have SGA infants or will develop hypertension.