Women with older partners may be at higher risk of suffering miscarriages irrespective of their own age, according to a study that has linked the increased chance of a failed pregnancy with men over the age of 40.
Until now it was widely assumed that miscarriage rates largely increased with female age only, but a study into women undergoing artificial insemination with their partner's sperm has found that it can also be linked with older men. Scientists also found that pregnancy rates fell as the male partner gets older. This may reflect a decline in sperm quality in men over 40 that affects both the chances of conception and the increased risk of a miscarriage, they said.
It is the first time scientists have discovered such a strong paternal effect on rates of pregnancy and miscarriage, and they suggest that, in future, fertility clinics should look more closely at the age of men as well as the age of women when advising on treatment.
Stephanie Belloc, of the Eylau Centre for Assisted Reproduction in Paris, said: "Until now the message was to get pregnant before the age of 35 or 38 because afterwards it would be difficult. But now the gynaecologists must also focus on paternal age and give this information to the couple.
"We suggest that there is a link between paternal age and DNA decay in the spermatozoa because we previously demonstrated that age is associated with increased sperm DNA fragmentation. So maybe there is a link between paternal age and DNA decay that are implied in the miscarriages.
"I think it's important to consider not only the woman, but both members of the couple in natural conception, but also in assisted reproductive technology ."
The scientists analysed data gathered at a fertility clinic that performs artificial inseminations directly into a woman's uterus, a technique which improves the conception rate.
They followed up 21 239 cases of these intrauterine inseminations to see whether the age of the man or the woman had any significant effect on the chances of conception and miscarriage.
As expected, they found maternal age was a strong factor in pregnancy rates, with just 8.9 percent of women over the age of 35 getting pregnant, compared with 14.5 percent in younger women.
"But we also found that the age of the father was important in pregnancy rates - men over 35 had a negative effect," said Belloc.
"And, perhaps more surprisingly, miscarriage rates increased where the father was over 35."
The study - the results of which were to be released this week at the European Society for Human Reproduction and Embryology in Barcelona - found the miscarriage rate among women with partners aged between 35 and 39 was 18.1 percent, but 33 percent for the partners of men aged between 40 and 44.
Couples undergoing assisted reproductive technology where the man is older than 35 or 40 should consider using the technique of intracytoplasmic sperm injection (ICSI), for directly injecting single sperm into an egg, because then the best sperm could be chosen for fertilisation, Belloc said.
"It's the conclusion of my study that ICSI should be the of choice when paternal age is increasing because we can choose the best spermatozoa.
"We can choose spermatozoa without DNA fragmentation, and DNA fragmentation is increasing with paternal age. So it is a way to be free of paternal age."
Older dads
- TV presenter Des O'Connor's wife, the Australian singer-songwriter Jodie Brooke Wilson (35), gave birth to their son Adam in September 2004. O'Connor, then 72, claimed: "It felt like the right time."
- US presidential hopeful John McCain was 48 when he and his wife Cindy had their first child together, the now-award-winning blogger Meghan McCain. They have since had two more.
- There were a few sleepless nights at the Playboy mansion in the early 1990s when a sexagenarian Hugh Heffner fathered sons Marston and Cooper by his fiancee Kimberley Conrad.
- When Leo Blair was born in 2000, 47-year-old Tony became the first serving prime minister to have a baby in more than 150 years.
- Actor David Jason became a dad for the first time aged 61 when his daughter, Sophie Mae, was born.
- A 56-year-old Michael Douglas welcomed Dylan Michel into the world in 2000, then married the mother, Catherine Zeta-Jones, soon afterwards. The couple had a daughter three years later. - The Independent