New research shows that men have a biological clock that affects the success of IVF pregnancies. Older fathers are more likely to experience miscarriages, even when the mother is younger.
Men can produce sperm throughout their lives. This means men can father children at any age, as seen with celebrities like Al Pacino and Mick Jagger, who had children in their 70s and 80s. However, male fertility does decline with age.
Previous studies showed that sperm from men over 45 has a lower chance of fertilizing an egg during IVF. Now, new research confirms that the father’s age also affects pregnancy outcomes after fertilization. IVF pregnancies with older fathers have a higher risk of miscarriage and lower live birth rates, even if the egg comes from a younger woman.
The study looked at 1,712 couples undergoing IVF. Among men aged 45 or younger, the miscarriage rate was 16.3%. For men over 45, the rate rose to 23.8%. The live birth rate dropped from 41% in younger men to 35.1% in older men.
Dr. Maria Cristina Guglielmo, an embryologist at the Eugin clinic in Italy, said, “Maternal age has long been the focus in fertility medicine, but our study shows that paternal age also plays a key role.” She will present the findings at the European Society of Human Reproduction and Embryology meeting in Paris.
The data came from six IVF centers in Italy and Spain, covering donation cycles from 2019 to 2023. The women donating eggs averaged 26 years old, while the women receiving eggs averaged 43.3 years. The average age of male partners was 43.5 years, with the older group averaging 49.6 years and the younger group 39.8 years.
Dr. Guglielmo explained that sperm from older men may have more DNA damage. This affects the sperm’s quality and the embryo’s development, leading to a higher risk of miscarriage.
She urged fertility clinics to inform male patients about the risks linked to older paternal age. “Even when using young donor eggs, the father’s age can impact pregnancy success,” she said.
The average age of women starting IVF passed 35 last year, prompting warnings to avoid delaying parenthood too long.
This study highlights the importance of considering both parents’ ages in fertility treatments. Men’s biological clocks matter, too.
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