Monden, Christiaan W. S., and Jeroen Smits, “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,” The Lancet Global Health 5, no.7 (May 2017), doi:10.1016/S2214-109X(17)30197-3

URL: www.thelancet.com/journals/langlo/article/PIIS2214-109X(17)30197-3/fulltext?elsca1=etoc

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Abstract

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 ¹ 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.

Understanding and analyzing the trends in twin mortality in sub-Saharan Africa has received little attention in medical literature. While neonatal mortality rates have declined in recent years, reduction in twin mortality is lagging significantly. Medical studies must pay greater attention to the unique health challenges these infants face, and the implementation of sustainable interventions must become a priority.