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

Abstract

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.

PIP: In the 1960's researchers followed 294 women between 19-30 years old from the last trimester of 1 pregnancy and subsequent lactation through a 2nd pregnancy and lactation in rural Taiwan to determine if maternal undernutrition adversely affects the growth and development of their children. They randomly assigned each mother either a chocolate flavored rich liquid supplement (group A) or a placebo that looked and tasted the same but with limited nutrient value (group B) 3 weeks after the 1st birth. No significant differences in mean birth weight, length, or head circumference existed either in males or females between groups A and B. A significant difference did exist, however, in mean birth weight between the 1st and 2nd group A males (p.05). The maternal nutrition supplement contributed to a mean weight gain of 162g for males. Therefore sex of the offspring mediated the effects of the maternal supplement. Further Rohrer's index of body proportion (weight/length cubed) indicated more sensitively the positive supplement effects in group A siblings. This was especially true when the older siblings had a dysmorphic growth pattern. Before receiving nutrient supplements and during the hot, humid summer months, mothers in both groups weighed less and their children weighed significantly less than the rest of the year. These differences no longer occurred during the 2nd pregnancy and lactation. Other significant mediators of supplement effects were maternal body size and an earlier infant of dysmorphic prenatal growth. In conclusion, nutritional supplementation did not bring about distinct differences between the absolute anthropometric values of groups A and B. Over many years women must have adapted to low nutrition intake by maintaining the ability to reproduce.