Prolactin has been known to support milk production and stimulate caregiving behaviour in mothers, but now a University of Otago study has found the hormone can also regulate body temperature during pregnancy.
Senior author and University of Otago School of Biomedical Sciences physiology researcher Dr Rosie Brown said adjusting body temperature was a critical function of the central nervous system and was vital to keep both the mother and foetus healthy.
The study showed prolactin was a key pregnancy hormone, acting within the brain’s hypothalamus to help regulate core body temperature throughout gestation, she said.
"Early on, core body temperature rapidly elevates, likely because of rising progesterone levels, then increased metabolic heat occurs thanks to foetal growth, maternal tissue growth and greater food intake."
"Despite all these thermal pressures, core body temperature actually reduces in late pregnancy, and we now know it is prolactin which helps keep a mum cool.
"This seems to be an important change to promote heat loss, and to ultimately provide a safe environment for the foetus, as hyperthermia can impact brain development."
Dr Brown said the finding provided a better understanding of how the changing hormones altered body functions and promoted the survival and wellbeing of a mother and her offspring.
"Obviously, that helps us understand what is happening at a cellular level during pregnancy, but understanding adaptable changes in body temperature in mammals may also be critical for animal reproduction in a world facing climate change.
"The prolactin pathway in the brain may be a mechanism that will help mammals adapt to future thermal challenges."
