Why You Might Crank Down the Thermostat Post Pregnancy, Study Explains

The postpartum period comes with some serious readjustments. From learning how to embrace your postpartum body to surviving on just a few hours of sleep, but one adjustment you might not be expecting—adjusting your thermostat. If you’ve noticed that your knocking your thermostat temp down a few notches postpartum, you’re not alone—and according to new research, there might be a biological reason behind it.

A recent study published in Molecular Metabolism reveals that the brain actually rewires itself during and after pregnancy, influencing how mothers perceive and respond to temperature. The research, conducted by scientists at Baylor College of Medicine, found that postpartum female mice consistently preferred cooler environments—well after giving birth and even after weaning their pups.

“We worked with mice and found that female mice prefer a cooler environment starting from late pregnancy and persisting in long-term postpartum,” said lead researcher Dr. Chunmei Wang. Not only did their core body temperature drop, but they also stopped seeking out warmer environments altogether—though they still avoided the cold.

So what’s going on? During pregnancy and especially lactation, a mother’s body temperature typically increases to support the baby’s development and milk production. But rather than just running hot, the brain kicks in to help cool things down. The researchers discovered that a specific group of neurons in the brain, called ERαPOA neurons (short for estrogen receptor alpha-expressing neurons in the preoptic area), become less responsive to warmth and more sensitive to cold after birth. This shift makes the body feel warmer and creates a stronger drive to seek out cooler environments—a built-in way to avoid overheating.

Like most things post pregnancy, these changes don’t bounce back immediately. Postpartum mice continued to prefer cooler temperatures long after weaning, suggesting that the brain’s temperature regulation system undergoes long-term—maybe even lasting—adjustments. In fact, when researchers switched off the same neurons in mice that had never been pregnant, they mimicked postpartum mice’s chill-seeking behavior.

While the study was conducted on mice, the implications for humans are significant. Human body temperature is known to fluctuate throughout pregnancy and after birth, but this study offers the first glimpse into how the brain may be driving these changes long after delivery.

So the next time you find yourself sleeping with the windows open or lowering the thermostat, know that it’s not just a fluke—it could be your brain’s way of keeping you cool as part of the massive, behind-the-scenes work it’s doing to help you recover and care for baby.