It is a well-known fact, for instance, that the happy chemical (oxytocin) rises in men once they become fathers, or even as they play with their young babies.
But, progressively more, experts are learning that men have physical responses to pregnancy in their partners as well and that these changes also take place on a hormonal level.
Thus, if your partner is pregnant, chances are that you are also going to experience some remarkable changes in your hormonal make-up and levels.
The phenomenon of sympathetic pregnancy has gained a lot of scientific sneering over the years, but it does appear that the male body does make some serious hormonal changes when it is partnered with a pregnant lady.
For example, dads often gain sympathetic weight during a partner’s pregnancy, a phenomenon that is believed to be an adaptive process to cope with the extra energy they will require after the child is born.
However, there has always abounded, a scholarly argument as to what actually happens to men’s hormones during a partner’s pregnancy.
A decline in Testosterone and Estradiol
Impending fatherhood can lower testosterone and estradiol for men, even before their babies are born, a study by the University of Michigan found.
Previous studies have shown that men’s hormones change once they become fathers, and there is some evidence that this is a function of a decline in some hormonal levels after the child’s birth.
However, this study is the first to show that the decline may begin even earlier, during the transition to becoming a father.
These changes could be a function of mental changes that men experience as they prepare to become fathers or changes in their loving relationships, or may indicate even physical changes that men experience along with their expectant partners.
In this research by the University of Michigan, researchers examined salivary testosterone, cortisol, estradiol, and progesterone in 29 expectant couples between the ages of 18 and 45.
The saliva samples were gotten up to four times during the prenatal period, at about 12, 20, 28 and 36 weeks of pregnancy.
Women showed large prenatal increases in all four hormones mentioned above, while men saw declines in testosterone, which is associated with aggression and parental care, and estradiol, which is associated with caregiving and bonding.
No changes were found in men’s cortisol, a stress hormone, or progesterone.
However, if you look into the science of what this estrogen variant does to the male brain, it begins to make more sense, since estradiol, as it turns out, is also a factor in aggressive behavior in men, and according to a 2014 research, plays a portion in advancing male libido.
Well, you can notice that neither of these traits are particularly desirable characteristics in fathers-to-be, who need to be focusing on gently bonding with their new babies, rather than running around, making fights and demanding their sexual right.
However, a limitation of this new study, which appears in the American Journal of Human Biology, is that the findings are that researchers do not have a comparison group of men who are not expecting a child for comparison, as it relates to lower testosterone.
Thus, we can’t completely rule out the probability that the changes are simply due to age or the passage of time.