Effects of nutritional interventions during pregnancy on birth, child health and development outcomes: A systematic review of evidence from low‐ and middle‐income countries

Background Optimal nutrition plays a crucial role in pregnancy. Poor maternal nutrition and maternal obesity has risk factors for serious fetal complications and neonatal outcomes, including intrauterine growth restriction, congenital abnormalities, stillbirth, low birth weight (LBW), preterm birth, fetal macrosomia, increased risk of neonatal infections, neonatal hypothermia, and neonatal death. The prevalence of maternal malnutrition is higher in low‐ and middle‐income countries (LMICs) (10–19%) when compared with high‐income countries, with variation by region and by country. Several behavioral interventions, including dietary control and exercise, have been found to reduce the risk of these adverse outcomes. However, none has reviewed dietary interventions to prevent maternal obesity in pregnant women. Objectives The review aims to assess the effectiveness of balanced energy protein (BEP) supplementation, food distribution programs (FDPs), and dietary interventions to prevent maternal obesity during pregnancy on birth, child health, and developmental outcomes. Search Methods We searched Cochrane Controlled Trials Register (CENTRAL), MEDLINE, Embase, CINAHL, and 12 other databases, and trials registers for ongoing studies up until April 2019. We also searched for gray literature from different sources and for citations on Google Scholar and Web of Sciences. We also checked the reference lists of included studies and relevant reviews and contacted the authors of studies for any ongoing and unpublished studies. The search was followed by title/abstract screening, full‐text screening and data extraction. Selection Criteria We included randomized control trials, and quasi experimental trials to evaluate the impact of nutritional interventions (BEP, FDP, and dietary interventions to prevent maternal obesity) compared to control or standard of care, among healthy pregnant women of any age living in LMICs. Data Collection and Analysis Two review authors independently assessed and screened studies for eligibility, extracted data, and assessed quality of the studies included in the review. We conducted a meta‐analysis of all reported primary and secondary outcomes. Subgroup analysis and GRADE assessment was performed for all reported primary outcomes. Main Results The review included 15 studies, of these, eight were on BEP supplementation, five on FDP, and two on interventions for obesity prevention. BEP supplementation may show a reduction in the rate of stillbirths by 61% (risk ratio [RR], 0.39; 95% CI, 0.19–0.80; three studies, n = 1913; low quality on GRADE), perinatal mortality by 50% (RR, 0.50; 95% CI, 0.30–0.84; one study, n = 1446; low quality on GRADE), LBW infants by 40% (RR, 0.60; 95% CI, 0.41–0.86; three studies, n = 1830; low quality of evidence on GRADE); small for gestational age (SGA) by 29% (RR, 0.71; 95% CI, 0.54–0.94; five studies, n = 1844) and increased birth weight by 107.28 g (mean difference [MD], 107.28 g; 95% CI, 68.51–146.04, eight studies, n = 2190). An increase of 107.28 g of birthweight is clinically significant in the countries where the intervention was provided. BEP supplementation had no effect on miscarriage, neonatal mortality, infant mortality, preterm birth, birth length, and head circumference. FDP may show improvement in mean birth weight by 46 g (MD, 46.00 g; 95% CI, 45.10–46.90, three studies, n = 5272), in birth length by 0.20 cm (MD, 0.20 cm; 95% CI, 0.20–0.20, three studies, n = 5272), and reduction in stunting by 18% (RR, 0.82; 95% CI, 0.71–0.94; two studies; n = 4166), and wasting by 13% (RR, 0.87; 95% CI, 0.78–0.97; two studies, n = 3883). There was no effect of FDP on miscarriage, maternal mortality, perinatal mortality, neonatal mortality, infant mortality, preterm birth, LBW, SGA, head circumference, and underweight babies. Studies on interventions for obesity prevention among pregnant women failed to report on the primary outcomes. The studies showed a 195.57 g reduction in mean birth weight (MD, −195.57 g, 95% CI, −349.46 to −41.68, two studies, n = 180), and had no effect on birth length, and macrosomia. Authors' Conclusions Our review highlights improvement in maternal, birth, and child outcomes through BEP supplementation and FDP during pregnancy. But, due to the small number of included studies and low quality of evidence, we are uncertain of the effect of BEP supplementation, FDP and dietary interventions for prevention of obesity on maternal, and child outcomes. Thus, further good quality research is recommended to assess the effect of these interventions on maternal, child and developmental outcomes.