It's well-documented what women can expect when they're expecting. But less is known about whether or not men go through similar changes. Alexandra Sifferlin from Time reports that a new study has shown men undergo significant hormonal changes as well.

The study was published in the American Journal of Human Biology. Researcher took 29 male and female couples expecting their first child and tracked their hormones levels of testosterone, cortisol, estradiol, and progesterone at weeks 12, 20, 28, and 36 of pregnancy. They tested these levels by taking saliva samples from the participants.

Women showed increases in all four hormones over the course of the study, while men showed dips in their testosterone and estradiol levels, and no changes to cortisol or progesterone levels. But there’s still a lot of questions as to why these changes happen and what benefit do they offer in nature.

Sifferlin suggests that prior research may hold some answers that attribute men's changing hormones to sleep disruptions or less sexual activity. There's also some that think the psychological apprehension of becoming a parent may be a trigger. What is known is more comparative test will have to be conducted in order to come to any legitimate conclusions. The authors did make a note on intentions for future study:

“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.”

Read more at Time

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