In a study conducted at Columbia University's Mailman School of Public Health and the New York Psychiatric Institute researchers found that increasing paternal age is significantly associated with increased rates of spontaneous abortion, a pregnancy loss occurring before twenty weeks of gestation.
Results indicate that as the male partner ages there is a steady increase in rate of miscarriage.
Women with partners aged 35 or older had nearly three times as many miscarriages as compared with women conceiving with men younger than 25 years of age. This finding is independent of the woman's age and not explained by other factors such as diabetes, smoking, or previous spontaneous abortions, and adds to the growing realization of the importance of paternal characteristics for successful reproductive outcome.
"There has been a tremendous amount of research on women, and how their characteristics affect pregnancy outcomes. Of course, women's importance and centrality to pregnancy cannot be overstated. However, scientists seem to have forgotten that men are equal partners in reproduction, and their influence should be studied to the same degree. Our group has focused on men's influence on the health of their offspring, and we have made some fascinating discoveries," said Karine Kleinhaus, MD, MPH currently in Columbia's Department of Psychiatry and first author of the study. "This study shows how a man's age affects the likelihood of miscarriage."
Earlier research by the Columbia scientists showed that older men's wives suffer from preeclampsia, while the offspring of older men are more likely to get schizophrenia. "This is not as surprising as it may sound at first, as it was already shown by other researchers that older men have more abnormalities in their sperm, and that their children are more susceptible to certain birth defects," observes Dr. Klienhaus. In fact, the American Society for Reproductive Medicine has set an upper age limit of 40 years old for semen donors because of the increased risk of genetic abnormalities in the offspring of older fathers.
The international team of scientists involved in the study used a large historical data set containing information on many characteristics of mothers and fathers that might contribute to spontaneous abortion. The researchers analyzed data from the ante-natal or post-partum interviews of 13,865 women. This data was recorded in the Jerusalem Perinatal Study, a population-based cohort derived from 92,408 births in Jerusalem in 1964-1976.