We all know that women undergo significant physical changes, inside and out, in carrying and birthing a child … but it turns out, male hormone changes are also at play.
The physical changes a woman undergoes during and after pregnancy are pretty obvious. So obvious we can be in no doubt women are biologically equipped to carry and bring new life into the world.
What’s less well known is that men’s bodies also transform as a result of becoming a father. A growing body of research – which has only really been conducted since the beginning of this 21st century – has found that men undergo significant hormonal changes when bub arrives. What’s more, it’s been found that this can happen whether you’re the biological father or not.
Let’s start with oxytocin, the so-called ‘love hormone’ which is crucial to the childbirth and breast-feeding connection between mother and child. Women receive a spike in oxytocin levels during and immediately after pregnancy but it’s been discovered that when the new baby arrives, so do men, particularly when they’re holding and playing with the little one.
Another significant thing to happen to a man’s body is that his testosterone level drops as a result of interacting with a newborn. This is likely a vestige of more savage, huntin’ and gatherin’ times, reducing a man’s impulse to undertake dangerous, risk-taking behaviour and instead focusing his mind and body on his nurturing role of both mother and baby.
“…we showed that fathers’ testosterone and caregiving change together through time – if men increased their time in childcare, their testosterone went down,” writes Dr Lee Gettler, a prominent researcher in this area at University of Notre Dame in the US. “When other scientists watched fathers and infants together, dads with lower testosterone were more affectionate and sensitive with their babies.”
Gettler and his team have also noted an increase in new fathers of prolactin—a hormone best known for helping women produce breastmilk. Why is it in men? Gettler says that the presence of prolactin goes back hundreds of millions of years to our animal ancestors—before mammals existed. “My team and I showed that fathers have higher prolactin than non-fathers, with prolactin being the highest when babies are most needy and vulnerable as infants… we have not found that dads with higher prolactin are more involved caregivers. This hints that prolactin might have some other role for dads. In other studies, dads with higher prolactin engaged their babies in more exploratory play, helping them gain new experiences in the world around them.
Higher prolactin can also make fathers more responsive and sensitive to infant cries, the research has found.
Other studies have found that these male hormone changes a new dad undergoes are more pronounced when they spend time along with caring, nurturing and playing with their newborn, lowering his testosterone further and making him more soothing with the new child.
For a more detailed look at Gettler’s studies on male hormones and fatherhood, click here.