Effects on birth weight and perinatal mortality of maternal dietary supplements in rural gambia: 5 year randomised controlled trial

Abstract

Objective: To test the efficacy in terms of birth weight and infant survival of a diet supplement programme in pregnant African women through a primary healthcare system. Design: 5 year controlled trial of all pregnant women in 28 villages randomised to daily supplementation with high energy groundnut biscuits (4.3MJ/day) for about 20 weeks before delivery (intervention) or after delivery (control). Setting: Rural Gambia. Subjects: Chronically undernourished women (twin bearers excluded), yielding 2047 singleton live births and 35 stillbirths. Main outcome measures: Birth weight; prevalence of low birth weight (<2500 g); head circumference; birth length; gestational age; prevalence of stillbirths; neonatal and postneonatal mortality. Results: Supplementation increased weight gain in pregnancy and significantly increased birth weight, particularly during the nutritionally debilitating hungry season (June to October). Weight gain increased by 201 g (P<0.001) in the hungry season, by 94 g (P<0.01) in the harvest season (November to May), and by 136 g (P<0.001) over the whole year. The odds ratio for low birthweight babies in supplemented women was 0.61 (95% confidence interval 0.47 to 0.79, P<0.001). Head circumference was significantly increased (P<0.01), but by only 3.1 mm. Birth length and duration of gestation were not affected. Supplementation significantly reduced perinatal mortality: the odds ratio was 0.47 (0.23 to 0.99, P<0.05) for stillbirths and 0.54 (0.35 to 0.85, P<0.01) for all deaths in first week of life. Mortality after 7 days was unaffected. Conclusion: Prenatal dietary supplementation reduced retardation in intrauterine growth when effectively targeted at genuinely at-risk mothers. This was associated with a substantial reduction in the prevalence of stillbirths and in early neonatal mortality. The intervention can be successfully delivered through a primary healthcare system. Key messages: In developing countries chronic maternal undernutrition is a prime contributor to the birth of over 25 million low birthweight babies annually and to high rates of neonatal mortality. An absence of well designed field trials has created uncertainty about the potential efficacy of maternal feeding programmes This large scale randomised controlled trial shows that dietary supplementation in pregnancy can be highly effective in reducing the proportion of low birthweight babies and perinatal mortality Incorporating supplementary feeding into a rural primary healthcare system is feasible Late pregnancy is the period most amenable to intervention