Energy and protein intake in pregnancy.
Level 1 - systematic review of randomized trials
Systematic review of controlled trials
PubMed 14583907 · doi:10.1002/14651858.CD000032
What was done
Authors conducted a Cochrane systematic review searching the Cochrane Pregnancy and Childbirth Group trials register (up to October 2002) for acceptably controlled trials evaluating dietary advice or actual supplementation/restriction of energy and protein in pregnant women. Primary outcomes examined were maternal weight gain, fetal growth, and pregnancy outcomes.
What was found
Nutritional advice (5 trials, n=1,134) increased energy and protein intake but yielded no consistent pregnancy outcome benefits. Balanced energy/protein supplementation (13 trials, n=4,665) modestly increased maternal weight gain and mean birth weight, substantially reduced small-for-gestational-age (SGA) births, showed no significant effect on preterm birth, and significantly reduced risks of stillbirth and neonatal death (effects were not larger in undernourished women). High-protein supplementation (2 trials, n=1,076) showed a nonsignificant decrease in mean birth weight, a significantly increased risk of SGA birth, and a nonsignificantly increased risk of neonatal death. Isocaloric protein supplementation (3 trials, n=966) also significantly increased SGA risk. Energy/protein restriction in overweight women (3 trials, n=384) significantly reduced weekly maternal weight gain and mean birth weight, with no effect on pregnancy-induced hypertension or pre-eclampsia. Quantitative effect sizes, odds ratios, and confidence intervals were not reported in the abstract.
Why it matters
This review demonstrates that while balanced macronutrient supplementation provides clear perinatal benefits, isolated high-protein supplementation and maternal energy restriction can impair fetal growth and may cause harm.
Limits
The abstract does not provide exact point estimates, odds ratios, or confidence intervals for the reported outcomes. Several sub-analyses (high-protein supplementation, isocaloric supplementation, and energy restriction) were based on small numbers of trials and limited total participant counts.
Cited by
- supports Across studies in pregnant women, low-protein diets lead to smaller babies.