M S Kramer1. 1. Faculty of Medicine, McGill University, 1020 Pine Avenue West, Montreal, Quebec, CANADA, H3A 1A2. mikek@epid.lan.mcgill.ca
Abstract
BACKGROUND: Observational and non-randomized studies have suggested that energy/protein supplementation in pregnant women increases gestational weight gain and fetal growth. OBJECTIVES: The objective of this review was to assess the effects of a balanced protein/energy supplement for pregnant women on gestational weight gain and on the outcome of pregnancy. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group trials register was searched. Date of last search: January 2000. SELECTION CRITERIA: Acceptably controlled trials of energy/protein supplementation for pregnant women in which the protein content of the supplement was 'balanced' (protein content less than 25% of total energy content). DATA COLLECTION AND ANALYSIS: One reviewer assessed trial quality and extracted data. Study authors were contacted for additional information. MAIN RESULTS: Thirteen trials were included. They were of variable quality. Balanced protein/energy supplementation was associated with modest increases in maternal weight gain (weighted mean difference 17 grams per week, 95% confidence interval 5-29 grams per week) and fetal growth (birth weight increase, weighted mean difference 25 grams, 95% confidence interval 4-55 grams). The reduction in risk of small for gestational birth was substantial, however (odds ratio 0. 64, 95% confidence interval 0.53-0.78). These effects did not appear to be greater in undernourished women, nor did they seem to confer long term benefits to the child. No significant effects were detected on preterm birth, but significant reductions in stillbirth and neonatal death (based on only 3 trials) appear important. REVIEWER'S CONCLUSIONS: Balanced energy/protein supplementation improves fetal growth and may reduce the risk of fetal and neonatal death. The evidence is insufficient to evaluate whether there are other potential benefits to pregnant women or their infants.
BACKGROUND: Observational and non-randomized studies have suggested that energy/protein supplementation in pregnant womenincreases gestational weight gain and fetal growth. OBJECTIVES: The objective of this review was to assess the effects of a balanced protein/energy supplement for pregnant women on gestational weight gain and on the outcome of pregnancy. SEARCH STRATEGY: The Cochrane Pregnancy and Childbirth Group trials register was searched. Date of last search: January 2000. SELECTION CRITERIA: Acceptably controlled trials of energy/protein supplementation for pregnant women in which the protein content of the supplement was 'balanced' (protein content less than 25% of total energy content). DATA COLLECTION AND ANALYSIS: One reviewer assessed trial quality and extracted data. Study authors were contacted for additional information. MAIN RESULTS: Thirteen trials were included. They were of variable quality. Balanced protein/energy supplementation was associated with modest increases in maternal weight gain (weighted mean difference 17 grams per week, 95% confidence interval 5-29 grams per week) and fetal growth (birth weight increase, weighted mean difference 25 grams, 95% confidence interval 4-55 grams). The reduction in risk of small for gestational birth was substantial, however (odds ratio 0. 64, 95% confidence interval 0.53-0.78). These effects did not appear to be greater in undernourished women, nor did they seem to confer long term benefits to the child. No significant effects were detected on preterm birth, but significant reductions in stillbirth and neonatal death (based on only 3 trials) appear important. REVIEWER'S CONCLUSIONS: Balanced energy/protein supplementation improves fetal growth and may reduce the risk of fetal and neonatal death. The evidence is insufficient to evaluate whether there are other potential benefits to pregnant women or their infants.