Man's Age Might be a Cause of Infertility
When it comes to age and fertility, women fear a “biological clock” and are urged to have children early. But men are rarely given the same advice and often don’t worry about fertility when postponing marriage and children.
But a growing body of research now shows the age of the potential father matters too. French researchers have collected data from more than 21,000 artificial inseminations involving 12,200 infertile couples. The data, presented yesterday at the 24th annual conference of the European Society of Human Reproduction and Embryology in Barcelona, found that pregnancy rates decrease and miscarriages increase when a father is over 35 years of age.
As a man gets older, his testosterone level naturally declines and, in turn, his sexual drive may wane. The quality of a man's semen also drops as he gets older. Despite this, he will continue to produce sperm no matter what his age is.
Male fertility also declines with age. Sperm quality starts to decrease from age 35. Male factors contribute to between 30 and 50% of all infertility cases and the male factor is the single largest reason for Australian couples to undergo IVF.
Dr. Stephanie Belloc, of the Eylau Centre for Assisted Reproduction in Paris, said this is the first time that such a strong paternal effect on reproductive outcomes has been shown.
In most of the cases studied, the couples were being treated because of the husband’s infertility, but the researchers analyzed the results in a way to separate out the male and female factors related to each pregnancy. The sperm of each partner was examined for a number of characteristics, including sperm count, motility and morphology. Clinical pregnancy, miscarriage and delivery rates were also recorded.
A warning for older men about the potential damage to the DNA in their sperm was sounded at the annual conference of the European Society of Human Reproduction and Embryology. Sergey Moskovtsev, of the Mount Sinai Hospital in Toronto, told the conference that an increase in the ages of mothers and fathers made this warning particularly significant.
The sperm from older men has been found wanting in new study from Columbia University's Mailman School of Public Health. The researchers found that older fathers are linked with increased rates of spontaneous abortion (miscarriage), and the older the man, the more the risk of miscarriage.
As expected, maternal age was a strong predictor of success. Intrauterine insemination, or IUI, led to pregnancy in 14.5 percent of women under 35, but just 8.9 percent in women over 35. Miscarriage rates were also typically affected by maternal age.
But notably, a similar effect was shown for men over 35, in both pregnancy rates and miscarriage rates.
“This research has important implications for couples wanting to start a family,” Dr. Belloc said. “Our research proves for the first time that there is a strong paternal age-related effect on IUI outcomes, and this information should be considered by both doctors and patients in assisted reproduction programs.”
In another research scientists examined the rates of successful pregnancies reported in 59 fertility clinics. 1,938 couples took part and found:
- A women younger than 30 years old was 25% less likely to conceive a baby if her male partner was 40 years or older.
- That a woman of 35 to 37 years was 50% less likely to conceive if the male partner was over 40 years old.
"Infertile," of course, does not mean that you can't conceive: It simply means that you have not been able to get pregnant in a year's worth of trying. And the cause of infertility may not be connected to the woman; in about 30 percent of cases, the problem can be traced to the man's sperm, and in another 30 percent of cases both the man's and woman's physiology contribute to the problem.
Because the data are based on men with known fertility problems, it’s not clear whether the results apply to all men as they age. However, previous studies have also suggested that the biological clock ticks for men too.