Women aren't the only ones who experience hormonal changes before having a baby. As it turns out, men also have some hormonal waves prior to becoming dads.
New research published in the American Journal of Human Biology looked at 29 couples expecting their first child. The researchers took salvia samples of the participants and measured their levels of the hormones testosterone, cortisol, estradiol, and progesterone. The couples' hormones were measured at weeks 12, 20, 28, and 36 of pregnancy.
It's long been proven that expectant women undergo hormonal changes, but less is known about the soon-to-be-papas. The new study shows that while women had increases in all four types of hormones, men had decreases in their testosterone and estradiol levels, but no significant changes in cortisol or progesterone.
It's the first research to evidence that prenatal testosterone changes can occur in expectant fathers, though the changes are still small compared to those observed in women.
The researchers did not compare the couples to other non-expectant couples, so exactly how great these changes are compared to couples who aren't expecting kids is undetermined. And scientists were unable to conclude why men experience these changes, though there are some speculations based on prior research.
For instance, prior studies have suggested that men's hormones change after becoming fathers as they adopt more nurturing behaviors. Or that drops in testosterone may reflect sleep disruptions or disruptions in sexual activity due to having kids. Some of these same behaviors may happen during pregnancy too. The psychological, emotional and behavioral changes of new parenthood could also cause hormonal waves in expectant dads.
"It will be important for future research to determine whether the changes that we observed in men’s hormones reflect processes associated with fatherhood specifically, or long-term pair-bonding more generally," the authors concluded.