Risk factors for spontaneous and provider-initiated preterm delivery in high and low Human Development Index countries: a secondary analysis of the World Health Organization Multicountry Survey on Maternal and Newborn Health.

OBJECTIVE: To evaluate how the effect of maternal complications on preterm birth varies between spontaneous and provider-initiated births, as well as among different countries. DESIGN: Secondary analysis of a cross-sectional study. SETTING: Twenty-nine countries participating in the World Health Organization Multicountry Survey on Maternal and Newborn Health. POPULATION: 299 878 singleton deliveries of live neonates or fresh stillbirths. METHODS: Countries were categorised into very high, high, medium and low developed countries using the Human Development Index (HDI) of 2012 by the World Bank. We described the prevalence and risk of maternal complications, their effect on outcomes and their variability by country development. MAIN OUTCOME MEASURES: Preterm birth, fresh stillbirth and early neonatal death. RESULTS: The proportion of provider-initiated births among preterm deliveries increased with development: 19% in low to 40% in very high HDI countries. Among preterm deliveries, the socially disadvantaged were less likely, and the medically high risk were more likely, to have a provider-initiated delivery. The effects of anaemia [adjusted odds ratio (AOR), 2.03; 95% confidence interval (CI), 1.84; 2.25], chronic hypertension (AOR, 2.28; 95% CI, 1.94; 2.68) and pre-eclampsia/eclampsia (AOR, 5.03; 95% CI, 4.72; 5.37) on preterm birth were similar among all four HDI subgroups. CONCLUSIONS: The provision of adequate obstetric care, including optimal timing for delivery in high-risk pregnancies, especially to the socially disadvantaged, could improve pregnancy outcomes. Avoiding preterm delivery in women when maternal complications, such as anaemia or hypertensive disorders, are present is important for countries at various stages of development, but may be more challenging to achieve.