The African continent has been identified as an area of high risk to increasing exposure of heat and has higher levels of social vulnerability. Heat exposure can lead to a rise in certain perinatal and maternal adverse health conditions. We explored the association of heat on seven perinatal and maternal health outcomes.

In this study, data is from Aga Khan University Hospital in Mombasa, Kenya. We evaluated the influence of heat exposure metrics on the outcomes of caesarean sections, low birth weight, low apgar score, preterm birth, stillbirth, assisted vaginal deliveries and long duration of stay in hospital. We carried out pooled time series regression using distributed-lag nonlinear models (lag 0–9 months).

We observed an increased odds of caesarean sections with heat exposure at lag 0 indicated by maximum daily Universal Thermal Climate Index (UTCI) between the 50th and the 95th percentile (relative risk 1.21 (1.01,1.46, 95 %CI)) and maximum daily temperature (1.25 (1.03,1.53)). There were increased odds of Low-Birth-Weight Births for lag 0 mean and maximum UTCI. We did not find any significant responses for Wet Bulb Globe Temperature (WBGT).

Our results show different risk responses for different heat exposure metrics for all perinatal and maternal health outcomes, significantly increasing for low-birth-weight births and caesarean sections. Further research is warranted for Kenya regarding maternal mortality and higher blood loss sometimes associated with caesarean deliveries. In addition, more research is needed on socioeconomics and heat exposure, especially in low– and middle income countries.