摘要：Objectives. To estimate the impact of hypothetical antimalarial and nutritional interventions (which reduce the prevalence of low midupper arm circumference [MUAC]) on the incidence of low birth weight (LBW). Methods. We analyzed data from 14 633 pregnancies from 13 studies conducted across Africa and the Western Pacific from 1996 to 2015. We calculated population intervention effects for increasing intermittent preventive therapy in pregnancy (IPTp), full coverage with bed nets, reduction in malaria infection at delivery, and reductions in the prevalence of low MUAC. Results. We estimated that, compared with observed IPTp use, administering 3 or more doses of IPTp to all women would decrease the incidence of LBW from 9.9% to 6.9% (risk difference = 3.0%; 95% confidence interval = 1.7%, 4.0%). The intervention effects for eliminating malaria at delivery, increasing bed net ownership, and decreasing low MUAC prevalence were all modest. Conclusions. Increasing IPTp uptake to at least 3 doses could decrease the incidence of LBW in malaria-endemic countries. The impact of IPTp on LBW was greater than the effect of prevention of malaria, consistent with a nonmalarial effect of IPTp, measurement error, or selection bias. Low birth weight (LBW; < 2500 g) remains a significant global health concern, affecting more than 25 million infants annually. 1,2 Low birth weight is associated with a marked increase in infant mortality and contributes to long-term morbidity. 1 In 2012, the World Health Organization (WHO) endorsed a target of 30% reduction in the incidence of LBW by 2025. As of 2014, the Global Nutrition Report found that there was little progress globally toward this goal. 3 Interventions in low- and middle-income countries (LMICs) to prevent LBW have the potential to produce substantial public health effects, ranging from improved cognitive development to enhanced neonatal survival. 1,2 Two important risk factors for LBW in many LMICs are maternal malnutrition and malaria infection during pregnancy. 4–6 In malaria-endemic countries, up to 1 in 4 pregnant women are infected with malaria, while up to 20% of women of childbearing age in LMICs suffer undernutrition (body mass index [BMI; defined as weight in kilograms divided by the square of height in meters] < 18.5). 2,5,7 Although these 2 factors are highly prevalent in LMICs, interventions for them are often evaluated independently. Our group, the Maternal Malaria and Malnutrition (M3) Initiative, has endeavored to better understand this coburden of malaria infection and malnutrition during pregnancy. Specifically, in a recent study in which we used data pooled from 13 studies across Africa and the Western Pacific, we found that women who were both infected with malaria and malnourished were at greater risk of delivering a LBW infant than their uninfected, well-nourished counterparts. However, there was no conclusive evidence of synergistic interaction between the 2 risk factors for LBW (i.e., the effects of malaria infection and nutritional status of the mother on LBW were independent of each other). 8 Although results from this study were informative for furthering our understanding of the biological mechanisms that affect fetal growth and development, policymakers would benefit from knowing how many cases of LBW could be prevented by interventions targeting malaria infection and maternal malnutrition. WHO policy for malaria prevention during pregnancy includes insecticide-treated bed nets, intermittent preventive treatment during pregnancy (IPTp), and prompt and effective case management. 9 Intermittent preventive treatment during pregnancy may also prevent LBW by preventing other infections because of its antibacterial properties, and by possible impacts on maternal nutritional status. 6 Currently, IPTp is recommended as repeated sulfadoxine and pryimethamine (SP) doses at least a month apart, starting in the second trimester, 9 but before 2007, only 2 doses of IPTp were recommended. Consistent with the lack of progress toward LBW reduction reported by the Global Nutrition Report, in 2013, an estimated 43% of 35 million eligible pregnant women did not receive any doses of IPTp. 10–12 The WHO endorses balanced energy and protein dietary supplementation during pregnancy among undernourished populations; however, interventions that would ameliorate poor nutrition before conception have received less focus. 2,13 The objectives of this study were 2-fold. First, we aimed to estimate the impact of implementing hypothetical targeted antimalarial interventions and reductions in the prevalence of low midupper arm circumference (MUAC; a proxy for malnutrition) on population-level estimates of LBW. Second, we aimed to examine whether the introduction of any combination of these hypothetical targeted interventions might meet the WHO goal of a 30% reduction in the incidence of LBW.
