Delaying fatherhood until later in life could have a negative effect on both children and mothers, new research has revealed.
Men who embark on the path to parenthood after the age of 45 are more likely to have unhealthy children. For example, men who were 45 or older were 14 percent more likely to have a child born prematurely, and men 50 or older were 28 percent more likely to have a child that required admission to the neonatal intensive care unit.
In future studies, Eisenberg plans on investigating some of the possible mechanisms at play to glean a better understanding of how a father's age might influence the baby and the mother's health.
As reported in the BMJ, the Stanford researchers examined data available for 40,529,905 births that took place between 2007 and 2016 for the influence of paternal age on various health outcomes of babies and mothers.
The children of fathers aged 45 plus were born an average of 20.2g lighter and were at a 14% greater risk of low birth weight (less than 2500g).
Newborns of fathers 45 and older are more likely to be underweight or wind up in intensive care, researchers reported Thursday, adding to the list of problems associated with older dads.
This is an observational study, so no firm conclusions can be drawn about cause and effect.
But they do believe that the new research highlights the importance of taking a dad-to-be's age into consideration.
The researchers stress that the absolute risks remain low, but say their findings emphasise the importance of including men in preconception care-and the need to further investigate the public health implications of rising paternal age within the U.S. and other developed countries.
Data from more than 40 million births showed that babies born to fathers of an "advanced paternal age", which roughly equates to older than 35, were at a higher risk for adverse birth outcomes, such as low birth weight, seizures and need for ventilation immediately after birth.
The study results follows more research released a year ago which revealed that men should also be more aware of their ticking biological clock. "So I do think it's becoming more relevant for us to understand the health ramifications of advanced paternal age on infant and maternal health".
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The new findings come just days after a study confirmed that women don't necessarily need to wait the previously recommended 18 months in between giving birth and getting pregnant again, news which was well received by many women anxious about their "biological clock". Follow Yahoo Lifestyle on Facebook, Twitter and Instagram.