Research by UCLA environmental economist Alan Barreca analysed weather patterns and trends in US birth rates, discovering that hot temperatures result in a decrease in procreation.
“If you look nine months after a heat wave in August, the following May you see significantly fewer births,” Barreca said in a statement.
And it’s not the excessive sweat and heat-induced lethargy that’s putting people off the act of reproduction, heat is having a significant impact on men’s sperm production. However, the study also demonstrated a rebound effect with birth rates increasing for several months after they were reduced due to a heat wave.
Barreca says that global warming will exacerbate this pattern and potentially push more couples into conceiving in the cooler months, shifting more births from spring into summer. He says that this has implications for prenatal health as studies suggest that hot weather during the third trimester can affect foetal health.
Researchers at the University of Alicante, for example, found this correlation when analysing the birth month of nearly 30,000 people in relation to 27 chronic diseases.
Professor Jose Antonio Quesada, who led the study, said birth month, “May behave as an indicator of periods of early exposure to various factors, such as exposure to ultraviolet rays, vitamin D, temperature, seasonal exposure to viruses and allergies which may affect the development of the uterus and neonate in their first months of life.”
Warming temps aren’t the only environmental issue influencing fertility – another study has linked increasing air pollution with slower swimmers.
While you can make more environmentally friendly choices and rally our government to take tangible action around climate change, there are other factors impacting fertility that you can have more of an influence on. Maintaining a healthy diet, exercising regularly, cutting back on drinking and quitting smoking have been found to improve fertility in both men and women.