Mortality among twins and singletons in sub-Saharan Africa between 1995 and 2014: a pooled analysis of data from 90 Demographic and Health Surveys in 30 countries

Background Sub-Saharan Africa has the world's highest under-5 and neonatal mortality rates as well as the highest naturally occurring twin rates. Twin pregnancies carry high risk for children and mothers. Under-5 mortality has declined in sub-Saharan Africa over the last decades. It is unknown whether twins have shared in this reduction. Methods We pooled data from 90 Demographic and Health Surveys for 30 sub-Saharan Africa countries on births reported between 1995 and 2014. We used information on 1 685 110 singleton and 56 597 twin livebirths to compute trends in mortality rates for singletons and twins. We examined whether the twin-singleton rate ratio can be attributed to biological, socioeconomic, care-related factors, or birth size, and estimated the mortality burden among sub-Saharan African twins. Findings Under-5 mortality among twins has declined from 327.7 (95% CI 312.0-343.5) per 1000 livebirths in 1995-2001 to 213.0 (196.7-229.2) in 2009-14. This decline of 35.0% was much less steep than the 50.6% reduction among singletons (from 128.6 [ 95% CI 126.4-130.8] per 1000 livebirths in 1995-2001 to 63.5 [61.6-65.3] in 2009-14). Twins account for an increasing share of under-5 deaths in sub-Saharan Africa: currently 10.7% of under-5 mortality and 15.1% of neonatal mortality. We estimated that about 315 000 twins (uncertainty interval 289 000-343 000) die in sub-Saharan African each year. Excess twin mortality cannot be explained by common risk factors for under-5 mortality, including birthweight. The difference with singletons was especially stark for neonatal mortality (rate ratio 5.0, 95% CI 4.5-5.6). 51.7% of women pregnant with twins reported receiving medical assistance at birth. Interpretation The fate of twins in sub-Saharan Africa is lagging behind that of singletons. An alarming one-fifth of twins in the region dies before age 5 years, three times the mortality rate among singletons. Twins account for a substantial and growing share of under-5 and neonatal mortality, but they are largely neglected in the literature. Coordinated action is required to improve the situation of this extremely vulnerable group. Funding None. Copyright (C) The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.