Babies born to older fathers may have a higher risk of health problems

Women constantly remember their biological clocks and the risks of having children later in life – both in terms of maternal and child health and the ability to conceive a baby. But in most cases, men do not receive the same warnings.

A new study published Wednesday in the BMJ suggests that men too can have biological clocks to watch. According to the newspaper, babies born to older fathers are more likely to suffer from health problems, including prematurity, low birth weight and respiratory problems. And women who have children with older men may also have increased health risks, including gestational diabetes.

"On an evolutionary level, we are used to reproducing in the late teens, early twenties," says co-author of the study, Dr. Michael Eisenberg, Director of Reproductive Medicine and surgery at Stanford University Medical Center. "Anything beyond that can be associated with a potential biological risk."

Despite our evolving roots, American women have more and more babies later in life, in part because many pursue careers and education before starting a family. The paternal age seems to follow the same pattern. Between 1972 and 2015, the average age of fatherhood rose from 27.4 to 30.9 years and the percentage of fathers over 40 years increased to about 9%, according to a study conducted in 2017.

There has been a lot of talk about health issues associated with "geriatric pregnancies", such as the higher probabilities of preterm birth, low birth weight, gestational diabetes and high blood pressure in the mother, both of which may affect the development of the baby and lead to complications. Eisenberg and his colleagues set out to determine if similar dangers apply to older fathers.

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Using data from the national vital statistics system, they analyzed more than 40 million live births in the United States between 2007 and 2016. (During this period, the The average age of fathers has increased from 30 to 31.2 years.) Fathers of these babies belonging to five age groups – aged 25, 25 to 34, 35 to 44, 45 to 54 years old and over 55 years old – and examined the measures of infant health in each of these categories.

After taking into account factors such as the age of the mother and the demographic and health information of the parents, the researchers found a link between the father's age and the likelihood of maternal and child health problems. Significant associations began to surface around age 45 and the data suggest that the older the father, the higher the risk.

Compared to infants born to men aged 25 to 34, infants whose father was over 45 years old tended to weigh less and were 14% more likely to deliver prematurely. Babies born to men over 55 also tended to have a lower Apgar test score, a measure of newborn health that assessed factors such as heart rate, breathing and reflexes. The researchers also found that these babies were 10% more likely to need respiratory assistance and 28% more likely to be admitted to the neonatal intensive care unit.

Women with a partner over the age of 45 were also 28% more likely to develop gestational diabetes than women with partners aged 25 to 34, the paper says.

The new study ties in with previous research that established a link between high paternal age and mental and behavioral health problems in children, such as autism, hyperactive deficit disorder, and autism. Attention and bipolar disorder. Although the reasons for these associations, as well as those detailed in the new document, are not entirely clear, they may have something to do with the spontaneous genetic mutations that occur throughout life. a man, according to research.

Men continually produce sperm, says Eisenberg, which means that their cells are constantly dividing and renewing themselves. From time to time, this process goes awry and results in about two random genetic mutations each year. The older a man is, the more he has accumulated these mutations over time and the more likely he is to transmit a harmful mutation, says Eisenberg. Older men may have also experienced more epigenetic changes, or changes in the DNA caused by the environment or lifestyle, than younger men, he adds.

Eisenberg points out that the absolute risk of child health problems is still low, even if the probability increases with the paternal age. He compares the probabilities with the purchase of lottery tickets: your chances of being better if you buy two, but it is still long.

According to Eisenberg, more and more evidence suggests that men should think seriously about when they have children. "Most of the risks associated with being an older parent are probably more about women than men, but I think it shows that we should not forget about the man," says he. "Men should not think of the track as unlimited."

Write to Jamie Ducharme at [email protected].