Maternal Weight and Body Composition during Pregnancy Are Associated with Placental and Birth Weight in Rural Bangladesh^1,2

Placental growth is a strong predictor of fetal growth, but little is known about maternal predictors of placental growth in malnourished populations. Our objective was to investigate in a prospective study the associations of maternal weight and body composition [total body water (TBW) estimated by bioelectrical impedance and fat and fat-free mass derived from upper arm fat and muscle areas (UAFA, UAMA)] and changes in these with placental and birth weights. Within a cluster- randomized trial of maternal micronutrient supplementation, a subsample of 350 women was measured 3 times across gestation. Longitudinal analysis was used to examine independent associations of;10-wk measurements and;10-20wk and;20-32wk changes with birth outcomes. Weight, TBW, and UAMA, but not UAFA, at;10wk were each positively and independently associated with placental weight and birth weight (P < 0.05). Of the maternal;10-20wk changes in measurements, only TBW change and placental weight, and maternal weight and birth weight were positively associated (P < 0.05). Gains in weight, TBW, and UAMA from 20 to 32wk were positively and UAFA gain was negatively associated with placental weight (P # 0.01). Gains in weight and UAMA from 20 to 32wk were positively associated with birth weight (P # 0.01). Overall, higher maternal weight and measures of fat-free mass at;10wk gestation and gains from 20 to 32wk are independently associated with higher placental and birth weight.