Several potential determinants of birth weight and neonatal behavioral organization, ie, maternal anthropometry, food intake (energy, protein, and plant- and animal-source foods), morbidity, and household socioeconomic status, were followed systematically in a semirural Egyptian population during greater than or equal to 6 mo of pregnancy. In early pregnancy mothers were generally normal weight to moderately overweight. Their mean energy intake, largely from plant sources, was approximately 8.37 MJ/d (2000 kcal/d) during trimesters 2 and 3. Early (3 mo) pregnancy weight and weight gain during trimesters 2 and 3 were significantly positively related to birth weight Z scores. The best predictor model examined for birth weight includedearly pregnancy weight, weight gain, and length of gestation (R2 = 0.45). Early pregnancy weight and maternal intake of animal-source foods were significant positive predictors of the newborn's orientation and habituation behavior, respectively. Habituation and orientation measures assess the infant's early ability to process information.