Man's age has a direct effect on fertility

Man's age has a direct effect on fertility: reportMatthew CouttsThe age of the potential father - not just the mother - can seriously limit the chances of having a baby later in life, according to a study released today.

While it has long been documented would-be mothers in their mid-30s or older face reduced pregnancy rates and increased miscarriages, researchers say this is the strongest proof to date that similar problems are caused by the age of the would-be father in couples that face difficulty conceiving.

Researchers at France's Eylau Centre for Assisted Reproduction monitored 21, 239 cases of intrauterine inseminations (IUI), an effective type of artificial insemination, in more than 12,000 couples between 2002 and 2006.

They found maternal age was closely associated with a decrease in the pregnancy rate - 8.9 per cent in women over 35 years, compared with 14.5 per cent in younger women - as well as a higher miscarriage rate.

"But we also demonstrated that the age of the father was important in the rate of pregnancy, with a negative effect for men over 40,'' said Stephanie Belloc, lead author of the study.

"And even more surprising, the proportion of miscarriages went up as well, '' she added.

The study, to be presented at the European Society of Human Reproduction and Embryology conference in Barcelona, showed paternal age led to decreases in the pregnancy rate, from 12.3 per cent with fathers 30 years of age or younger, to 9.3 per cent in fathers older than 45 years of age. The rate of miscarriage more than doubled over the same periods, from 13.7 per cent to 32.4 per cent.

In most cases the couples were being treated at the clinic because the husband had infertility issues, but researchers say the findings relate to men without such problems. "There is no doubt that we can extrapolate from the study to men in general,'' said co-author Yves Menezo, also a researcher at the Eylau Centre.

In IUI the sperm is "washed'' in order to separate them from the seminal fluid, and then inserted directly into the uterus. The goal is to increase the chances of fertilization and remove any chemicals in the semen that may cause discomfort for the woman.

Belloc said sperm with DNA damage, common in older men, was still able to enter the egg during IUI, but the weakened sperm could result in failure to conceive. While previous reports show a decline in sperm count and quality in older men, this is the first clinical proof that a man's age has a direct effect on fertility.

National Post, with files from AFP