Heatwaves linked to 34% higher risk of perinatal death in sub-Saharan Africa, study finds

A recent study published in journal Nature Medicine has revealed a significant link between high temperatures in the final week of pregnancy and an increased risk of perinatal death in sub-Saharan Africa. The study found that babies whose mothers were exposed to extreme heat the week before childbirth faced a 34 per cent higher risk of stillbirth or neonatal death within 24 hours of birth.

Extreme heat has been previously associated with adverse pregnancy outcomes, including preterm birth, low birthweight and stillbirth. Heat stress on mothers can disrupt foetal development and increase complications during labour. Additionally, heatwaves can indirectly impact perinatal health by straining healthcare systems, causing delays in care and reducing access to essential services.

Sub-Saharan Africa already bears the highest burden of neonatal mortality worldwide, with 27 deaths per 1,000 live births in 2022, followed by central and southern Asia with 21 deaths per 1,000 live births. Despite this, there has been little research examining the relationship between temperature in the final week of pregnancy and perinatal mortality in the region.

The study analysed 138,015 births across 16 hospitals in Benin, Malawi, Tanzania and Uganda between July 2021 and December 2023, observing the effects of rising temperatures on perinatal outcomes. The largest sample size came from Malawi, while Tanzania contributed the smallest sample.

The researchers from Karolinska Institute and others defined high temperatures as an increase from a typically warm week (22-28 degrees Celsius) to an exceptionally warm week (24-29°C), depending on the country. The study also found that the risk of perinatal death was notably higher during the six hottest months of the year, with stillbirths being more strongly associated with heat exposure.

A significant finding was that 44 per cent of stillbirths in the study occurred during labour. The research, however, only represented 30-40 per cent of hospital births. Poorer women in remote or rural areas, who may be more vulnerable to heat stress, were underrepresented in the sample.

The findings underscored the urgent need for interventions to protect pregnant women in sub-Saharan Africa from the dangers posed by rising temperatures, as climate change continues to exacerbate extreme weather patterns.