Pregnancy does a number on dads-to-be, research shows

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Updated: November 27, 2011 1:21PM

F or years, we have heard about how pregnancy can affect a woman’s hormones, causing dramatic changes in her body and her brain function. However, up until recently, little research has been done on fathers’ brains, likely because people assumed there would not be much (if any) hormonal or physical changes in a daddy-to-be.

Apparently, this assumption was quite incorrect. Recent research has discovered that there actually are dramatic changes in a man’s brain during his partner’s pregnancy. Within four to six weeks of learning about his impending baby, a man’s levels of cortisol typically increase.

Cortisol is a hormone that is associated with one of our most basic survival tools: the fight-or-flight syndrome. For thousands of years, cortisol has helped humans to survive by giving us that extra boost of adrenaline that we need during times of danger and stress, and I think most parents-to-be will agree that the thought of a new baby can be quite stressful indeed. The extra boost of cortisol helps dads to tackle challenges and effectively prepare for the baby. Think of it as nature’s energy shot!

Testosterone levels also undergo changes during pregnancy. In the first few weeks after his child’s birth, a man’s testosterone levels drop by about a third. Testosterone is responsible in assisting with many of the body’s functions, such as playing a key role in a man’s sexual desire. There are many possible reasons for this drop. One reason is that a high level of sexual desire could pose a big problem for new parents. Most moms-to-be simply do not have the energy or the desire for sexual contact, and even as their desire slowly returns, the baby’s needs still come first during this crucial stage.

While men can understand their partner’s lack of energy and desire from a mental point-of-view, it might be hard for them to override their physical desires if their bodies are still awash in testosterone. Hence, nature intervenes once again, this time by causing a little drop in that “must-have-sex” mode and switching Dad to a lower level.

And it isn’t just that Mother Nature is romantic in nature and wants couples to stay together for the heck for it. Thousands of years ago, before the days of hospitals, pre-made baby food, diapers, and all the amenities of modern life, a baby needed two parents to survive. Cavemen and women didn’t have baby nurses, and they didn’t have protection from wild animals or the elements, so working together as a team was a must. (Of course, even though we don’t have to worry about saber-toothed tigers anymore, having two loving, involved parents remains crucial in a baby’s life!)

Another reason that testosterone might drop is because it helps new dads switch into caretaking mode. Research has found that men with lower levels of testosterone might be better at adapting to nurturing behaviors (one study found that men with low levels of testosterone were likely to hold a baby doll for a longer time period than men with high levels of testosterone.)

This could be because oxytocin (the “bonding” chemical that occurs during breastfeeding and creates feelings of intimacy and tenderness) might have a higher impact on the brain if lower levels of testosterone are present. So, even though dads can’t breastfeed, their brains might be preparing them for this nurturing, thereby helping them to be loving fathers.

Additionally, research has long linked testosterone and aggressive behaviors. Clearly, the last thing a new baby needs is an angry, aggressive dad, so this might be another reason why testosterone drops during this time.

As research on fatherhood continues, I hope these findings serve as a reminder that dads are more than just baby-sitters. Not only do they have the desire to be amazing and loving dads, but their very bodies are preparing them for this journey every step of the way. So, moms, take a step back and let dad have a little more responsibility and hands-on time with the baby. You deserve the me time, and he deserves time with his baby — not to mention, his baby deserves time with him!