Effects of prenatal nutritional supplementation on the placenta: report of a randomized controlled trial.

Protein and nucleic acid content, and RNase levels were measured in placentas collected at birth in a randomized controlled trial of prenatal nutritional supplementation in New York City. These biochemical indices were explored to understand better the effects of nutritional supplementation. (With high-protein supplements, gross measures had shown no improvement in outcome at birth and adverse effects on fetal growth, prematurity, and newborn survival; with balanced protein-calorie supplements, there was a nonsignificant rise in birth weight and longer gestation.) The biochemical indices were in general somewhat weakly related to fetal growth measures. Significant effects of nutritional treatment on the indices were minimal, and added no information that could account for gross effects observed in the fetus.