Late Age Fatherhood Can Damage Male Fertility

Delaying fatherhood can substantially affect a woman’s pregnancy, as well as a man's fertility, a French research suggests. According to this new study, a woman’s chance of conceiving a baby decreases and miscarriage risk increases when her spouse is over 40 years of age.

The study, carried out by scientists at France’s Eylau Centre for Assisted Reproduction, warns that the couple who wish to have babies should better not delay the time of conceiving too much if the man is in his mid-thirties.

The research team, lead by Dr Stephanie Belloc, from the Eylau Centre for Assisted Reproduction in Paris, found that men who were over the age of 40 faced problems with fertility, while miscarriage rates increased significantly when the prospective father was older than 35 years of age and pregnancy rates dropped after the age of 40.

"Until now, gynaecologists only focused on maternal age and 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," said Dr Belloc.

To reach their findings, the French scientists looked at a total of 21,239 intrauterine insemination (IUI) cases in more than 12,000 couples between January 2002 and December 2006.

IUI is a particularly effective type of artificial insemination, an introduction of sperm into the female reproductive tract by means other than a partner's penis. When IUI is done, the sperms are washed or separated from seminal fluid in a centrifuge and then inserted directly into the uterus. Intrauterine insemination is used to induce pregnancy in women whose partners cannot impregnate them.

After examining the IUI cases, the researchers found that the pregnancy rate in women over 35 years of age decreased by nearly 10% when men were over the age of 40. This group of women also showed significantly high rates of miscarriage compared to younger women.

The study, presented Monday at the 24th annual conference of the European Society of Human Reproduction and Embryology (ESHRE) in Spain, is one of its kinds, suggesting that the age of men is important when trying to conceive.

"We already believed that couples where the man was older took longer to conceive," said Dr. Belloc. "But how DNA damage in older men translates into clinical practice has not been shown up to now."

The findings will be published in the British journal Reproductive Biomedicine.