Maternal body weight and relation to birth weight.

In The Stockholm Pregnancy and Weight Development Study the relationships between birth weight and maternal initial body weight as well as weight increase during pregnancy were analysed in 2,295 subjects. As expected, the most important predictor of birth weight was total maternal weight increase, followed by initial maternal body weight. However, in women with an initial BMI value above 24 kg/m2, birth weight did not increase significantly in tact with maternal weight. The frequency of cesarean sections, 12% overall, was not significantly increased with maternal body weight. These data show that birth weight increases with maternal weight only up to the upper normal body weight.