Outcome of maternal nutritional supplementation: a comprehensive review of the Bacon Chow study

In a double blind controlled intervention, two groups of nutritionally at-risk rural Taiwanese women were given a nutrient-rich dietary supplement (group A, n = 114) or a placebo (group B, n = 111) beginning after the birth of one child and continuing through the lactation period for a subsequent child. Outcome variables assessed include infant birth measurements postnatal physical growth, motor, mental, and dental development, morbidity, and maternal weight and skinfold changes during pregnancy and lactation. While few A-B differences in mean values of outcome variables were found, there were significant responses in subgroups of the sample. Comparisons of infants born after a nutrient-supplemented pregnancy (A2) versus an unsupplemented pregnancy (A1) showed that A2 male infants weighed more than A1 males at birth, and A1-A2 sibling correlations in birth measurements, especially Rohrer's index (wt/l3) were significantly reduced. Important mediators of supplement effects included sex of the offspring, season of birth, maternal body size, and birth of a previous infant characterized by dysmorphic prenatal growth. The limited effects of supplementation on the population as a whole may reflect the operation of long term adaptations which allow women to maintain reproductive success despite their apparent marginal nutritional status.