1214 GMT March 27, 2019
Researchers at Stanford University in California studied health records linked to all live births in the US between 2007 and 2016, amounting to more than 40 million babies. The records showed that children born to men aged 45 and over had a 14 percent greater risk of premature birth, low birth weight and being admitted to neonatal intensive care compared with babies born to younger fathers, according to The Guardian.
Infants born to men aged 45 and over also scored lower on the Apgar newborn health test, and were 18 percent more likely to have seizures compared with infants born to fathers aged 25 to 34 years, according to the study in the British Medical Journal. For women, the risk of gestational diabetes was greater when they had children with older men.
Michael Eisenberg, a senior author on the report, said that while the increased risks were modest, couples should not ignore the father’s age when it came to family planning. “This is something else to take into consideration,” he said. “There are potential risks with waiting. Men should not think that they have an unlimited runway.”
But Eisenberg stressed that the increased risks for individuals were small. After adjusting for the mother’s age and other factors such as education and whether she smoked, he found that children born to men aged 45 and over were born less than a day earlier on average, and weighed only 20g lighter (just over half an ounce) than those with younger fathers.
More important, said Eisenberg, was the impact modest increases in health risks might have across populations as paternal age continues to rise. In England and Wales, the average age of first-time fathers has risen about a year per decade for the past 40 years, according to the Office of National Statistics.
Eisenberg and his colleagues suggested changes in the DNA of older men’s sperm might explain their findings. The concern is backed up by previous work, including a Harvard study last year that found births through IVF fell as the fathers’ age increased.
In a commentary accompanying the BMJ study, Hilary Brown, a perinatal epidemiologist at the University of Toronto in Scarborough, cautioned that despite the researchers’ efforts, it was hard to disentangle the effects of the mother’s and father’s ages. And she warned that damage to DNA in older mens’ sperm was only one possible explanation for the effects.
“Studies have shown that advanced paternal age is associated with negative health behaviors such as smoking and frequent alcohol consumption, obesity, chronic disease, mental illness, and sub-fertility,” she wrote, adding that all are linked to health problems in newborns.