The transformation of women’s bodies and health during motherhood has long fascinated us, shedding light on its impact on hormones, cognitive abilities, relationships, and even cancer and disease susceptibility.
However, a growing body of evidence indicates that even though men do not physically experience childbirth, they also go through both physical and psychological changes upon becoming fathers.
A recent study involving 624 men revealed a one-third reduction in testosterone levels coinciding with the birth of their children. Researchers from Northwestern University in Chicago noted that this decline encourages less aggressive behavior and promotes a nurturing disposition in men.
Dr. Allan Pacey, a fertility expert at the University of Sheffield, remarks, ‘While profound changes occur in women during pregnancy, the shifts in men are more nuanced.’
According to Dr. Craig Garfield, an assistant professor of pediatrics at Northwestern University, ‘This is just the beginning of our understanding of how fatherhood impacts men’s health. Some findings appear beneficial, while others indicate risks. It’s an exciting area of study.’
Experts share surprising insights into the ways fatherhood influences both the male body and mind.
One particularly fascinating revelation about fatherhood is its impact on men’s personalities. Recent research in the U.S. observed that testosterone levels fell by 34 percent after a partner gives birth.
This hormone is linked to aggressive and dominant behaviors, leading researchers to conclude that a decrease in testosterone may indicate that men are ‘hard-wired’ for parenthood, mirroring the experiences of women.
They have adapted to safeguard their offspring and genetic legacy by becoming more gentle and nurturing when their children are born.
Dr. Pacey elaborates: ‘Although a dip in testosterone might not directly make a man more child-friendly, it does realign his priorities toward investing in the new infant. It would be intriguing to learn whether similar changes occur in stepfathers.’
‘Is this reduction in testosterone triggered by the presence of a child and an increased sense of social responsibility, or does it stem from scents and hormonal cues indicating this is your offspring?’
In our closest primate relatives, evidence suggests the latter may be the case. Another group of U.S. researchers examined male marmosets, among a few primates like humans who share caregiving roles. After exposing the males to the scent of their offspring, testosterone levels dropped significantly within 20 minutes.
Dr. Garfield emphasizes the need for further exploration into how such hormonal changes could influence men’s health. ‘We know that hormones from pregnancy and breastfeeding offer women some protection against certain cancers, like breast and ovarian; it’s conceivable that hormonal fluctuations in men might also offer health benefits.’
Nonetheless, some experts propose that the reasons behind the changing testosterone levels may be simpler, attributing them to physical reactions to stress.
‘In fathers, cortisol levels frequently increase around their partner’s pregnancy,’ states Dr. Mark Vanderpump, an endocrinologist at the Royal Free Hampstead NHS Trust in London. ‘Cortisol, known as the stress hormone, primarily helps maintain blood pressure during stressful situations. However, as cortisol increases, testosterone production tends to decline.’
‘The pregnancy of their partner may represent a stressful event, leading to a question of whether the decrease in testosterone is specifically linked to…‘The evolution is not clear.’
Many fathers will tell you that their priorities changed significantly with the arrival of their baby, and some scientists hypothesize that the brains of fathers may function differently.
In 2006, a study conducted by researchers at Princeton University focused on the brains of male marmosets and discovered that following childbirth, the brain cell connections in the prefrontal cortex — the area linked to planning and memory — were more efficient.
Given that these abilities are crucial for new parents, the researchers inferred that a similar enhancement could occur in the human brain. A subsequent study by the same team revealed that fatherhood led to the formation of new cells and connections in the hippocampus region — an area connected to emotional processing — in male mice.
According to a 2009 survey of 5,000 men, the average expectant father gains around a stone during his partner’s pregnancy. Approximately 40 percent attributed this weight gain to the additional snacks made available due to their partner’s increased appetite, while others noted receiving larger portions or eating more to help their partner feel more comfortable with her changes.
However, this phenomenon may be more complex, as similar behavior has been observed in male marmosets, which can gain up to 20 percent of their body weight during their mate’s pregnancy. The male monkeys develop a pregnancy belly in anticipation of the extra energy needed when the baby arrives.
A recent survey of 2,000 men found that one in four expectant fathers experience many of the pregnancy ‘symptoms’ alongside their female partners.
These men reported cravings for food, mood fluctuations, and feelings of nausea — with some even expressing experiences akin to phantom pregnancy pains.
The increased involvement of modern fathers in pregnancy-related activities (such as attending antenatal classes and scans) is believed to contribute to the phenomenon referred to as ‘pregmancy’.
‘Today, society expects men to take an interest in their child and to understand what their partner is going through,’ explains social psychologist Dr. Sandra Wheatley. ‘For them, attending scans makes the experience more tangible — just as it does for women. Thus, it’s not surprising they begin to experience psychosomatic symptoms.’
Dr. Wheatley also adds that these so-called sympathy symptoms might be a physical manifestation of a man’s anxiety regarding his partner’s discomfort.
‘We often observe this in individuals who are close to cancer patients; they reflect their worry about their loved one’s health through physical symptoms, like nausea.’
A study published last month in the journal Human Reproduction analyzed data from 135,000 men, revealing that those without children had a 17 percent higher likelihood of dying from a heart condition.
What might cause this? Dr. Ian Banks, a visiting professor of men’s health in Europe at Leeds Metropolitan University, attributes it to lifestyle choices.
‘When men become parents, they begin to contemplate their longevity. They modify their eating habits, quit smoking, and reduce their visits to pubs with friends.’
Dr. Banks highlights a successful public health initiative aimed at reducing heart disease, which utilized family photos showing the father absent. ‘This campaign had a significant effect,’ he mentions.
He also notes that single, childless men are less likely to visit their GP, but once they become fathers, they engage with healthcare professionals more frequently — allowing GPs to discuss health with them.
Testosterone is associated with sex drive, and it’s believed that hormonal changes after pregnancy may encourage a man to be more monogamous.
‘A decrease in testosterone levels would result in reduced libido, making the man less interested in sexual activity,’ states Dr. Pacey. ‘This seems logical, given that the partner will also be less inclined.’By returning to routine, the likelihood of him searching for alternatives is reduced.
A study conducted last month indicated that this effect is not lasting, as men’s testosterone levels tend to increase again as the child matures.
At the University of California, researchers found that after becoming fathers, male monkeys display heightened sensitivity to vasopressin. This hormone, produced in the brain’s pituitary gland, is believed to stimulate bonding feelings between a male and his partner.
According to a study from last year, men are just as susceptible to postnatal depression as women are.
The East Virginia Medical School analyzed 43 studies across 16 countries, revealing that one in ten fathers—mirroring the number for mothers—might experience this condition before or after the birth.
Dr. Roger Henderson, a GP and author of the book “Dad’s Guide To Pregnancy For Dummies,” refers to it as the male baby blues. “It can severely impact relationships,” he states.
The decrease in testosterone, a hormone associated with sex drive and energy levels, may contribute to this issue. “I encounter many men who experience psychological fatigue, which can be caused by low testosterone levels,” explains Dr. Henderson.
Additionally, factors such as a father’s shifting role within the family and experiencing a traumatic birth can increase the risk.
Problems for men are most common between three to six months post-birth. While a woman’s body and lifestyle undergo significant changes at the moment of pregnancy, her partner often continues working until the delivery, leaving little time for emotional preparation for the new arrival.
“Men suddenly realize that everything is about to change,” Dr. Banks notes. “Yet, they tend to keep it to themselves. During my time in obstetrics, I encountered numerous men eager to express their emotions—it’s not surprising that this suppression can lead to depression.”
He encourages women to motivate their partners to engage in discussions.
“Men lack the means to cope, and there is no education available for them.”
by Susan Floyd