Objectives: To assess the effects of providing pregnant women with high-protein nutritional supplements on gestational weight gain and on the outcome of pregnancy, including fetal growth, gestational duration, and maternal and fetal/infant morbidity and mortality.
Search strategy: The register of clinical trials maintained and updated by the Cochrane Pregnancy and Childbirth Group.
Selection criteria: All acceptably controlled comparisons of protein/energy supplementation in which the protein content of the supplement provided >25% of its total energy content.
Data collection and analysis: Data were extracted by the author from published reports, and supplemented by additional information from trialists contacted by the author.
Main results: Two studies involving 1076 women were included. High protein supplementation was associated with a small, statistically nonsignificant increase in weekly maternal weight gain. The two available trials provide no evidence of benefit on fetal growth; indeed, the adjusted mean difference in birth weight is -58. 4 g. One trial also reported a nonsignificantly increased risk of neonatal death with high-protein supplementation.
Reviewer's conclusions: There is not enough evidence to evaluate the use of high protein supplementation in pregnancy.