This study investigated the effects of maternal changes during pregnancy in diet, exercise, and psychosocial factors on offspring weight parameters at birth and 6 months. In overweight/obese (OW/OB;n=132) mothers, greater % kcal from sweets early in pregnancy was the strongest, independent predictor of higher weight for age (WFA) (beta=0.19;P=0.004), higher odds of macrosomia (OR = 1.1 (1.0–1.2);P=0.004) andWFA>90th percentile at birth (OR = 1.2 (1.1–1.3);P=0.002) and higher WFA at 6 months (beta=0.30;P=0.002). In normal weight (n=153) mothers, higher intake of soft drinks was the strongest predictor of higher offspring WFA at birth (beta = 0.16;P=0.04) but not at 6 months. Prenatal physical activity, depressive symptoms, and sleep-related variables did not significantly predict offspring weight outcomes. Mothers’ eating behaviors during pregnancy, especially intake of sweets in OW/OB mothers, may have a lasting effect on child weight.