Maternal weight, weight gain and birthweight at term in the rural Tanzanian village of Ilula.

In an area-based study in a rural Tanzanian village, the relations of maternal weight and weight gain during pregnancy to birthweight were analysed for 331 term deliveries. The distribution of body-mass index, used as an indicator of maternal nutritional status, was similar to the pattern seen in Sweden, although mean maternal height (156 cm) was 9 cm below that of Swedish women. Mean initial weight measured at week 14 was 53 kg and total pregnancy weight gain was 6 kg. Women weighing greater than or equal to 60 kg in early pregnancy gained less weight (0.16 kg/week) than those weighing less than 50 kg (0.22 kg/week). Birthweight was correlated both with maternal weight in early pregnancy and with weight gain during pregnancy, but only 10% of the variation in birthweight was explained by these maternal factors. Mean maternal weight 24 h postpartum was equal to the weight at 14 weeks of pregnancy, implying, on the average, no net weight gain. Women with a positive net weight gain had heavier babies than women with a negative net weight gain. Maternal anthropometric characteristics are important underlying determinants of intrauterine growth and birthweight, but they explain only a minor part of the variation and are of little value for screening purposes in individual women.