Heatwave Exposure and Maternal Outcomes: A Multicenter Retrospective Study in Kano Metropolis Hospitals, Northwestern Nigeria

BACKGROUND: Extreme heat events are increasing due to climate change, with potential implications for maternal health, particularly in low-resource, hot-climate settings such as northern Nigeria. Evidence on heatwave effects in this context remains limited. AIM: This study assessed maternal outcomes during periods of varying heat exposure in selected hospitals in Kano Metropolis, Northwestern Nigeria. METHODS: A retrospective cross-sectional study was conducted using aggregated monthly hospital records from three referral hospitals over a 12-month period (November 2024 and October 2025). Months were categorized into heatwave (March–June) and non-heatwave (July–February) periods based on seasonal temperature patterns. Data on postpartum hemorrhage (PPH), pregnancy-induced hypertension (PIH), antepartum hemorrhage (APH), severe preeclampsia/eclampsia (SPE/E), spontaneous vaginal delivery (SVD), cesarean section (C/S), and maternal death (MD) were extracted using a validated checklist. Independent samples t tests compared mean monthly outcomes, and Poisson regression assessed associations between seasonal high-heat exposure and maternal outcomes. RESULTS: Most maternal outcomes did not differ significantly between heatwave and non-high-heat periods. However, C/S rates were significantly higher during heatwave months. Poisson regression analysis indicated that seasonal high-heat exposure was associated with a higher rate of cesarean delivery (incidence rate ratio = 1.40; 95% confidence interval [1.18, 1.66]; p < .001). No significant associations were observed for PPH, PIH, APH, SPE/E, SVD, or MD. CONCLUSION: Seasonal high-heat exposure was not associated with significant changes in most maternal outcomes at the studied hospitals, although C/S rates increased during high-heat periods. Strengthening climate-resilient maternal health care systems is essential as extreme temperature events become more frequent.