As heatwaves become more frequent, multiple species face increasing risks to survival and reproduction. Pregnancy is a particularly vulnerable period, and although research into heat effects on pregnancy has increased, the underlying mechanisms and trimester-specific effects are poorly understood. We combine research on live-bearing insects with epidemiological analysis on humans to understand mechanisms and temporal dynamics of heat stress during pregnancy.
2. Methods
We compared upper thermal tolerance (measured as critical thermal maximum (CTmax)) among males and females (non-pregnant, early and late-stage pregnant (n=30 per group)), examined differences in body composition between stages of pregnancy and ran heatwave simulations.
We are also investigating temporal dynamics of heat exposure in human pregnancy by conducting analyses across birth records in Southwest-England spanning the last 15 years. These analyses aim to examine heatwave exposures across pregnancy stages and how they affect birth outcomes such as preterm birth, embryo loss and low birthweight to determine any critical windows of exposure.
3.Results
We first present data on the Pacific beetle-mimic cockroach Diploptera punctata, a viviparous experimental model, to examine thermal tolerance and response to experimental heatwaves. We found increased thermal tolerance in pregnant females with body composition analyses suggesting this is partially explained by body mass but not lipid or protein variation. Our analysis suggests that, beyond mass variation, additional physiological adaptations during pregnancy may contribute to increased thermal tolerance. We then exposed pregnant females to simulated heatwaves early and late in pregnancy and found that females produced smaller offspring and showed a trend towards spontaneous abortion when exposed to high temperatures late in pregnancy.
4. Conclusion
By combining experimental studies in a viviparous model with large-scale clinical data analysis, this project aims to provide insight into how heat affects pregnancy across species, giving evolutionary and epidemiological insights into this global health challenge.