Source:
https://scmp.com/lifestyle/health-wellness/article/2171869/babies-born-older-fathers-more-likely-have-health-problems
Lifestyle/ Health & Wellness

Babies born to older fathers more likely to have health problems, study finds

  • Researchers say newborns are more likely to be underweight and need intensive care, and are at greater risk of a seizure, if father is over 45
  • Changes in male reproductive cells could be to blame
The average age of fatherhood has been steadily rising in wealthy nations, as has the percentage of fathers above 45 and 55. Photo: Alamy

Newborn babies whose fathers are 45 and older are more likely to be underweight or wind up in intensive care, researchers reported last week, adding to the list of problems associated with older dads.

For fathers 55 and up, infants tended to score worse in a standardised test used to assess the baby’s health immediately after birth.

Even more startling – and harder to explain – was a heightened risk of diabetes arising during pregnancy for women carrying the child of a man 55 and older, according to a study published in the medical journal BMJ.

All these conclusions, the researchers cautioned, are based on an analysis of medical records rather than a controlled experiment, which means no firm conclusions about cause and effect can be drawn.

The overall risk of such outcomes also remained low, they added.

An underweight baby in an incubator. Researchers found that children born to fathers 45 or older were on average 20 grams (0.7 ounces) lighter, and had a 14 per cent higher risk of low birthweight than infants born to younger dads. Photo: Alamy
An underweight baby in an incubator. Researchers found that children born to fathers 45 or older were on average 20 grams (0.7 ounces) lighter, and had a 14 per cent higher risk of low birthweight than infants born to younger dads. Photo: Alamy

But the findings held true even after other factors that might skew the results – age of the mother, maternal smoking, level of education – were taken into account, they said.

“A significant number of these negative birth outcomes were estimated to be prevented if older fathers had elected to have children before the age of 45,” the scientists concluded.

“The risk associated with advanced paternal age should be included in discussions regarding family planning and reproductive counselling.”

The average age of fatherhood has been steadily rising in wealthy nations, as has the percentage of fathers above 45 and 55.

In the United States, the number of births to men 40 and older has almost doubled to 9 per cent over the last 40 years. For men over 50, the percentage has gone up from 0.5 per cent to nearly 1 per cent.

Similar trends are found in western Europe. In England, for example, fathers over 35 accounted for 40 per cent of all births in 2003, compared with 25 per cent in 1993.

The researchers found that pregnant women carrying the child of a man 55 or older were at a heightened risk of diabetes. Photo: Alamy
The researchers found that pregnant women carrying the child of a man 55 or older were at a heightened risk of diabetes. Photo: Alamy

To date, most research on the link between the age of parents and health outcomes in children has focused on older mothers.

But recent studies suggest that being a father later in life may also be associated with higher risks of autism, genetic abnormalities and mental problems in offspring.

One possible culprit is thought to be changes with age in male reproductive cells that affect the way genes are expressed, rather than the genes themselves.

To better understand the possible impact of advanced-age fatherhood on infants and mothers, researchers led by Michael Eisenberg of Stanford University combed through data on more than 40.5 million births in the United States from 2007 to 2016.

Children born to fathers 45 or older were on average 20 grams (0.7 ounces) lighter, and had a 14 per cent higher risk of low birthweight – less than 2.5 kilos (5.5 pounds) – than infants born to younger dads.

These children were also 14 per cent more likely to be admitted to a neonatal intensive care unit, and had 18 per cent higher odds of experiencing a seizure compared with infants of fathers aged 25 to 34.

The risk of gestational diabetes, meanwhile, for women carrying the child of a man aged 55 or older increased by 34 per cent.

The researchers further estimate that 13 per cent of premature births were attributable to fathers of more advanced age.