Nutritional supplementation during two consecutive pregnancies and the interim lactation period: effect on birth weight.

The study consisted of 169 mothers enrolled during two consecutive pregnancies and the intervening lactation period in the Guatemalan Nutritional Supplementation Study. Women were grouped for this analysis according to the levels of caloric supplementation that they received (high or low) during two consecutive pregnancies and the period between them. The supplement also contained minerals and vitamins. Data were analyzed adjusting for maternal height, birth interval, parity, length of lactation, socioeconomic status, birth weight of the first offspring, gestational age of the second offspring, and caloric supplementation, expressed either in continuous fashion (total intake) or as caloric supplementation per week. The adjusted mean birth weights of the second offspring of women with high supplementation during two pregnancies (about an extra 180 kcal/d), and the in-between lactation period (about an extra 245 kcal/d), were up to 301 g greater than that of the low supplementation group. Women with high supplementation while breast-feeding their first offsprings and during their second pregnancies had babies up to 150 g heavier than the reference group; those mothers with high supplementation only during the second pregnancy had infants about 124 g heavier than those of the low supplementation group. Therefore, high supplementation during two consecutive pregnancies and their intervening lactation period among chronically, yet moderately, malnourished women was capable of increasing the mean birth weight to levels closer to those reported for industrialized populations. The mean birth weight increase is between two and three times greater than the effect shown in almost all of the previous studies of this topic.