Science and Tech


Dads-To-Be Also Experience Hormone Changes During Pregnancy

A study from University of Michigan researchers found that expectant fathers see a decrease in testosterone as the baby's birth draws near.
Posted at 6:47 PM, Dec 18, 2014

Expectant parents have a lot to look forward to through the duration of a pregnancy — Lamaze classes, for one.

"Nothing can prepare you for the battle that is childbirth, unless of course you've given birth before or have been repeatedly kicked in the stomach by a kangaroo." (Video via YouTube / BYUtv)

There's also the feeling of "Hey, did I put this crib together properly?" and the bundle, or bundles, of joy at the end of the road. 

Studies have shown mothers go through hormonal changes along the way — and we totally understand why — but they aren't the only ones. Dads experience hormonal changes of their own. 

In a study involving 29 expectant heterosexual couples, University of Michigan researchers tracked levels of four different hormones: salivary testosterone, cortisol, estradiol and progesterone. Levels in all four hormones increased dramatically in women during their pregnancies, but researchers also noticed a gradual decrease in testosterone and estradiol in expectant fathers within the same time periods.  

Previous studies have shown new dads experience a decrease in testosterone once their children are born. But the lead author of this most recent study found testosterone begins to drop much earlier for soon-to-be-proud papas.

Unfortunately, researchers still don't know exactly why testosterone drops. In this 2011 New York Times article, the writer cites experts who say the lower testosterone numbers suggest "men’s bodies evolved hormonal systems that helped them commit to their families once children were born" and "it underscores that mothers were meant to have child care help."

There were limitations with this most recent study, like sample size and demographic variety of study participants. But going forward, researchers said it'll be important to see whether hormonal changes in men are associated with fatherhood or general "pair-bonding." The study is published in the American Journal of Human Biology.

This video includes images from Bethany Brown / CC BY NC SA 2.0mooasaurus / CC BY NC SA 2.0sandragxh / CC BY NC ND 2.0Sean / CC BY NC SA 2.0 and Kris / CC BY NC ND 2.0.