Effects of a liquefied petroleum gas cookstove and fuel intervention on fetal and neonatal outcomes: a multi-country randomized controlled trial conducted by the Household Air Pollution Intervention Network (HAPIN) trial

Background and aim Household air pollution (HAP) from cooking with solid fuels used during pregnancy has been associated with adverse pregnancy outcomes. The HAPIN trial is a randomized controlled trial of liquefied petroleum gas (LPG) stoves and fuel distribution in 3200 households conducted across Guatemala, India, Peru, and Rwanda. We describe the effects of the LPG intervention on fetal/infant stillbirth, neonatal mortality and congenital anomalies. Methods Pregnant women (18-35 years of age; gestation confirmed by ultrasound at 9-20 weeks) were randomly assigned to an intervention arm (n=1593) or control arm (n=1607). Participants were monitored for stillbirth (fetal death ≥ 20 weeks gestation), neonatal mortality (death of any live-born infant in first 28 completed days of life), and congenital anomalies (any structural/functional anomalies that occur during intrauterine life). Analyses were performed according to intention-to-treat (ITT) analysis, and binary outcomes were compared between the two arms using log binomial models. Results Pregnant women were enrolled in the study and received their LPG stoves at 15.4 (SD 3.1) weeks gestation. We recorded 47 congenital anomalies (23 intervention, 24 control), 56 stillbirths (28 intervention, 28 control), and 41 neonatal deaths (20 intervention, 21 control) between enrollment and 28 days of live of the infant. Compared to the control arm, the relative risk among women randomized to the intervention was 0.96 (95% CI: 0.55, 1.70) for congenital anomaly, 1.01 (95% CI: 0.60, 1.70) for stillbirth and 0.97 (95% CI: 0.53, 1.77) for neonatal mortality. Conclusions We did not find a significant reduction in incidence of stillbirth, neonatal mortality and congenital anomalies. The small number of cases may have contributed to the lack of power and the intervention was introduced after the first trimester, which may be too late to find a protective effect. Keywords: household air pollution; congenital anomalies, stillbirth, neonatal mortality. intention-to-treat, HAPIN trial