Few data exist for the effects of multiple micronutrient (MM) or food supplementation to undernourished pregnant women on their offsprings' development. We aimed to compare the effects on infant development of early (8-10 wk gestation) or usual ( approximately 17 wk gestation) supplementation with food and MM, 30 mg Fe + 400 microg folate, or 60 mg Fe + 400 microg folate. A large, randomized, controlled trial of pregnancy supplementation was conducted in Bangladesh. A subsample of infants (n = 2853) were assessed on 2 problem-solving tests (support and cover tests), the motor index of the Bayley Scales of Infant Development, and Wolke's behavior ratings at 7 mo of age. There were no significant effects of any intervention in the group as a whole. However, infants of undernourished mothers [body mass index (BMI; in kg/m2) < 18.5] who received early food supplementation performed slightly but significantly (P = 0.035) better on the support test than did infants of mothers who received usual food supplementation (z score: 0.17; 95% CI: 0.01, 0.33). There were no benefits in infants of higher-BMI mothers (P = 0.024 for BMI x food interaction). Children of low-BMI mothers who received MMs had slightly better motor scores (z score: 0.28; 95% CI: 0.08, 0.48) and activity ratings (z score: 0.24; 95% CI: 0.037, 0.45) than did those who received 30 mg Fe + 400 microg folate, whereas other children did not benefit (P = 0.05 for both motor scores and BMI x micronutrients and for activity and BMI x micronutrients). Small benefits from early food and MM supplementation were found in infants of low-BMI but not of high-BMI mothers. However, the benefits were of doubtful functional importance, and longer follow-up is required to determine programmatic implications.