A couple's risk of having a pregnancy end in miscarriage appears to rise
along with the father's age, regardless of how old the mother is, researchers
reported Monday.
Their study, of nearly 14,000 women who were pregnant in the 1960s and 70s,
found that the risk of miscarriage was 60 percent greater when the father was
age 40 or older than when he was 25 to 29 years old.
What's more, age made a difference even for men in their 30s. Miscarriage
risk was about three times greater when the man was between 35 and 39 years of
age than if he were younger than 25.
These risks were all independent of the mother's age, a well-known factor in
miscarriage, the researchers report in the journal Obstetrics & Gynecology.
The findings add to evidence showing that, like women, men have a biological
clock.
Although men continually produce new sperm and can father children even in
their golden years, research shows that their fertility gradually declines
starting at a relatively young age. Also, as with women, older fathers are more
likely to have children with birth defects.
One recent study found that a man's ability to have a child fades after the
age of 40, similar to a woman's fertility decline after age 35. Another
confirmed that genetic abnormalities in sperm steadily become more common as men
age.
Miscarriages, particularly those in the first trimester, often occur because
of genetic anomalies in the fetus, which may explain the risk tied to paternal
age.
The current findings strengthen the belief that couples planning a family
should consider not only the woman's age, but the man's as well, according to
the study authors.
"As child-bearing is increasingly delayed in Western societies, this study
provides important information for people who are planning their families,"
write the researchers, led by Dr. Karine Kleinhaus, who was with the Columbia
University School of Public Health in New York at the time of the study.
The findings are based on data from a large study of women in Jerusalem who
were pregnant between 1964 and 1976, about 1,500 of whom suffered a miscarriage.
These women were compared with the more than 12,000 study participants who
delivered a baby.
Older paternal age was linked to a higher miscarriage risk, regardless of
both the woman's age and a range of other factors that contribute to
miscarriage, such as smoking during pregnancy and maternal diabetes.
Still, the researchers point out, despite this generally higher miscarriage
rate, older paternal age may only slightly raise the risk to any one
couple.
