Indirect causes of severe adverse maternal outcomes: a secondary analysis of the WHO Multicountry Survey on Maternal and Newborn Health

[[[ Objective: ]]] To assess the proportion of severe maternal outcomes resulting from indirect causes, and to determine pregnancy outcomes of women with indirect causes. [[[ Design: ]]] Secondary analysis of the WHO Multicountry Survey on Maternal and Newborn Health. [[[ Setting: ]]] A total of 359 health facilities in 29 countries in Africa, Asia, Latin America, and the Middle East. [[[ Sample: ]]] A total of 314 623 pregnant women admitted to the participating facilities. [[[ Methods: ]]] We identified the percentage of women with severe maternal outcomes arising from indirect causes. We evaluated the risk of severe maternal and perinatal outcomes in women with, versus without, underlying indirect causes, using adjusted odds ratios and 95% confidence intervals, by a multilevel, multivariate logistic regression model, accounting for clustering effects within countries and health facilities. [[[ Main outcome measures: ]]] Severe maternal outcomes and preterm birth, fetal mortality, early neonatal mortality, perinatal mortality, low birthweight, and neonatal intensive care unit admission. [[[ Results: ]]] Amongst 314 623 included women, 2822 were reported to suffer from severe maternal outcomes, out of which 20.9% (589/2822; 95% CI 20.1-21.6%) were associated with indirect causes. The most common indirect cause was anaemia (50%). Women with underlying indirect causes showed significantly higher risk of obstetric complications (adjusted odds ratio, aOR, 7.0; 95% CI 6.6-7.4), severe maternal outcomes (aOR 27.9; 95% CI 24.7-31.6), and perinatal mortality (aOR 3.8; 95% CI 3.5-4.1). [[[ Conclusions: ]]] Indirect causes were responsible for about one-fifth of severe maternal outcomes. Women with underlying indirect causes had significantly increased risks of severe maternal and perinatal outcomes.