Women who gain more fat during pregnancy may not have bigger babies: implications for recommended weight gain during pregnancy.

The correlation between infant birthweight and the amount of fat gained during pregnancy (estimated as the change in maternal weight between 10 weeks gestation and 2-3 weeks postpartum) was studied in 115 healthy, parous, urban Scottish housewives. There was very little correlation between these variables (r = 0.13, falling to r = 0.07 after birthweight was adjusted for initial maternal weight and length of gestation), i.e., women who gained more fat during their pregnancies did not give birth to heavier babies. This suggests that for most women one of the principal effects of increasing food intake during pregnancy may be to increase maternal fat gain rather than promote fetal growth, and that efforts to increase birthweight by encouraging greater weight gain during pregnancy may be unsuccessful.