Although studying the effect of supplementation on maternal health or the outcome of pregnancy was not a primary goal of the Institute of Nutrition of Central America and Panama Oriente Longitudinal Study, many important findings in these areas were produced. As part of the study, a food supplementation program was implemented. Two villages received Atole, a gruel containing protein and energy, and 2 matched villages received a refreshing, low-energy drink containing no protein. Both drinks contained micronutrients. Some women did not choose to consume the supplements and those who did consumed widely varying amounts. More volume of Fresco was consumed than Atole. The energy in the supplements improved birthweight, with no apparent additional benefit from protein or micronutrients. Researchers identified several groups of women who benefited from supplementation more than others by having babies with higher birthweights, including those with poorer current nutritional status and those who consumed high amounts of the supplement continuously from one pregnancy to the next. Results from the study provided an early indication that supplementation might increase the duration of gestation and, thus, reduce preterm birth. On the other hand, maternal supplementation did not substantially alter the duration of postpartum amenorrhea once concurrent infant supplementation was taken into account. Finally, findings from this study provided evidence of a biological trade-off between maintenance of maternal nutritional status and increasing fetal size that was responsive to both current maternal nutritional status and supplement intake but not to the mother's nutritional status earlier in life.