Maternal morbidity and preterm birth in 22 low- and middle-income countries: a secondary analysis of the WHO Global Survey dataset

Background: Preterm birth (PTB) (<37weeks) complicates approximately 15 million deliveries annually, 60% occurring in low-and middle-income countries (LMICs). Several maternal morbidities increase the risk of spontaneous (spPTB) and provider-initiated (piPTB) preterm birth, but there is little data from LMICs. Method: We used the WHO Global Survey to analyze data from 172,461 singleton deliveries in 145 facilities across 22 LMICs. PTB and six maternal morbidities (height <145 cm, malaria, HIV/AIDS, pyelonephritis/UTI, diabetes and pre-eclampsia) were investigated. We described associated characteristics and developed multilevel models for the risk of spPTB/piPTB associated with maternal morbidities. Adverse perinatal outcomes (Apgar <7 at 5 minutes, NICU admission, stillbirth, early neonatal death and low birthweight) were determined. Results: 8.2% of deliveries were PTB; one-quarter of these were piPTB. 14.2% of piPTBs were not medically indicated. Maternal height <145 cm (AOR 1.30, 95% CI 1.10-1.52), pyelonephritis/UTI (AOR 1.16, 95% CI 1.01-1.33), pre-gestational diabetes (AOR 1.41, 95% CI 1.09-1.82) and pre-eclampsia (AOR 1.25, 95% CI 1.05-1.49) increased odds of spPTB, as did malaria in Africa (AOR 1.67, 95% CI 1.32-2.11) but not HIV/AIDS (AOR 1.17, 95% CI 0.79-1.73). Odds of piPTB were higher with maternal height <145 cm (AOR 1.47, 95% CI 1.23-1.77), pre-gestational diabetes (AOR 2.51, 95% CI 1.81-3.47) and pre-eclampsia (AOR 8.17, 95% CI 6.80-9.83). Conclusions: Maternal height <145 cm, diabetes and pre-eclampsia significantly increased odds of spPTB and piPTB, while pyelonephritis/UTI and malaria increased odds of spPTB only. Strategies to reduce PTB and associated newborn morbidity/mortality in LMICs must prioritize antenatal screening/treatment of these common conditions and reducing non-medically indicated piPTBs where appropriate.