Expectant mothers worried about their chances of having a premature baby may want to be more mindful of the weather.
“Our findings indicate that it may well be prudent to minimize the exposure of pregnant women to extremes in temperature,” said Pauline Mendola, researcher at the National Institutes of Health (NIH).
The first seven weeks of pregnancy are crucial, according to the study. It’s at this time that heatwaves or cold spells can lead to early delivery.
But for a woman exposed to extreme heat for most of her pregnancy, there were risks of preterm birth as well.
“[Researchers] theorized that, during cold spells, people are more likely to seek shelter and so could more easily escape the cold’s effects,” according to NIH. “But during extreme heatwaves, people are more likely to endure the temperature, particularly when the cost of or access to air conditioning is an impediment.”