A new international study has found that IVF cycles with male partners over 45 have higher miscarriage rates and lower live birth rates. This is true even when using eggs from young donors.
The study was presented at the 41st Annual Meeting of the European Society of Human Reproduction and Embryology (ESHRE). It focused on male age by using only young donor eggs, separating it from female reproductive factors. This provides strong evidence that male age matters for successful reproduction. It challenges the idea that sperm age has little effect after fertilization.
Researchers looked back at 1,712 first donor egg IVF cycles. These cycles happened between 2019 and 2023 at six clinics in Italy and Spain. All used fresh eggs from donors with an average age of 26.1. They also used frozen sperm from male partners. Only the first transfer of a single high-quality embryo was included. The women receiving the eggs were about 43.3 years old on average.
The men in the study were split into two groups. One group had 1,066 men aged 45 or younger. The other had 646 men over 45. Fertilization rates and embryo growth were similar in both groups. But their clinical results were different.
Miscarriage rates were higher for men over 45. They reached 23.8%, compared to 16.3% for younger men. Live birth rates were lower too. Men over 45 had a 35.1% rate, while younger men had 41%.
Dr. Maria Cristina Guglielmo is an embryologist at Eugin Italy. She said, “Reproductive medicine has long focused on the mother’s age. But our results show the father’s age also plays a key, independent role. Even with young, healthy donor eggs and a single high-quality embryo, men over 45 had worse results.”
Dr. Guglielmo explained why this might happen. “As men get older, their sperm cells divide more. This raises the chance of DNA mistakes. It leads to more new genetic mutations and abnormal chromosomes in sperm. Older men also have more damaged sperm DNA and changes in how genes work, like DNA methylation.”
She added, “These factors hurt sperm quality and genetics. They can slow embryo growth and raise miscarriage risk.”
Dr. Guglielmo noted what this means for clinics. “Our findings show fertility clinics need to pay more attention to the father’s age. This is true even in donor egg cycles, where the mother’s factors are controlled. Clinics should tell male patients how getting older can affect their fertility, pregnancy success, and miscarriage risk.”
Looking forward, Dr. Guglielmo said, “We plan to study the biology behind how a father’s age affects outcomes. We’ll focus on sperm DNA damage, cell stress, and gene changes.”
She also wants to study how older fathers affect children’s health. “There’s more evidence that older fathers may raise the risk of neurodevelopment disorders in kids. We’ll look at long-term health and development in children from donor egg cycles with older fathers. This will help us see the father’s effects more clearly.”
Professor Dr. Carlos Calhaz-Jorge is the immediate past chair of ESHRE. He said, “This study is important. It draws attention to a factor often ignored in IVF. It would be interesting to study older groups, like men over 55, to see if results are even worse. But the current findings should be part of counseling for couples where the man is over 45.”
Related topics:
