RHL Commentary by Gunilla Lindmark
EVIDENCE SUMMARY
Five interventions –previously reviewed separately- addressing energy and protein intake in pregnancy have been included in this Cochrane review.
Nutritional advice:
Advice to pregnant women to increase energy and especially protein intake seems to increase these intakes slightly, but no health benefits for infants or mothers have been documented, except in one study in which a reduction in preterm births was observed although this finding was not consistent with the lack of effect on mean gestational age or birth weight found in the same study.
Balanced energy/protein supplementation:
Compared with no energy supplementation, energy supplementation during pregnancy (300-850 kcal/day with less than 25% of that energy coming from protein) is associated with moderate increases in maternal weight gain and birth weight, and a substantial reduction in the risk of small for gestational age (SGA) infants (Relative risk [RR]: 0.68; 95% Confidence interval [CI]: 0.56 0.84). Three trials found important reductions in stillbirths (RR: 0.55; 95% CI: 0.31 0.97) and possibly neonatal deaths although this was not statistically significant (RR: 0.62; 95% CI: 0.37 1.05). In the few studies with follow-up in the postnatal period, neither any evidence of lasting weight improvement in mother or baby, nor of improved neurocognitive development at one or five years, was found.
High protein supplementation:
Two trials with 1076 women were included. There were no beneficial effects on any of the maternal or fetal outcomes and a statistically nonsignificant increase in neonatal death (RR: 2.78; 95% CI: 0.75 10.36) in one trial that provided data on this outcome.
Isocaloric protein supplementation:
Isocaloric protein supplementation, (in which less than 25% of the energy content of the supplement comes from protein), when compared to the same level of energy supplementation, was associated with a reduction in maternal weight gain as well as mean birth weight and increase in the risk of an SGA infant (one trial, RR: 1.35; 95% CI: 1.12 1.61). No change in gestational age distribution has been noted. Studies are not large enough to give reliable information on possible effects on perinatal mortality and do not give information on maternal health outcomes other than weight gain.
Energy/protein restriction in overweight or with high weight gain women:
384 women participated in the three trials included. Energy/protein restriction reduced the weekly weight gain but there was inadequate evidence to assess any substantial beneficial or adverse effect on the mother and the baby.
Overall, the methodology of the review seems to be rigorous and the trial characteristics are presented in detail.
The full RHL commentary also includes sections on: Relevance
- Magnitude of the problem
- Applicability of the results
- Implementation of the intervention
Research
References
This document should be cited as: Gunilla Lindmark. Energy/protein intake in pregnancy: RHL commentary (last revised: 31 October 2003). The WHO Reproductive Health Library, No 9, Update Software Ltd, Oxford, 2006. www.rhlibrary.com
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