The impact of intermittent presumptive treatment for malaria in pregnancy on hospital birth outcomes on the Kenyan coast
BACKGROUND: Intermittent preventive treatment (IPTp) to pregnant women with sulfadoxine-pyrimethamine (SP) is widely implemented for the prevention of malaria in pregnancy and adverse birth outcomes. The efficacy of SP is declining and there are concerns that IPTp may have reduced impact in areas of high resistance. Here we sought to determine the protection afforded by SP as part of IPTp against birth outcomes in an area with high levels of SP resistance on the Kenyan coast. METHODS: A secondary analysis of surveillance data on deliveries at the Kilifi County hospital between 2015 and 2021 was undertaken in an area of low malaria transmission and high parasite mutations associated with SP resistance. A multivariable logistic regression model was developed to estimate the effect of SP doses on the risk of low birthweight (LBW) deliveries and stillbirths. RESULTS: Among 27,786 deliveries, three or more doses of IPTp-SP were associated with a 27% reduction in the risk of LBW (adjusted odds ratio (aOR): 0.73; 95% CI: 0.64, 0.83; p < 0.001) compared to no-dose. A dose-response association was observed with increasing doses of SP from the second trimester linked to increasing protection against LBW deliveries. Three or more doses of IPTp-SP were also associated with a 21% reduction in stillbirth deliveries (aOR: 0.79; 95% CI: 0.65, 0.97; p= 0.044) compared to women who did not take any dose of IPTp-SP. CONCLUSIONS: The continued, significant association of SP on LBW deliveries suggests that the intervention may have a non-malaria impact on pregnancy outcomes.