Aug. 31, 2001 -- As women wait longer and longer to have babies, an increasing number are having fertility problems that require medical attention. New research shows that the age at which women reach menopause, and by extension the age at which their fertility will start to diminish, may be largely in the genes.
"We're pretty concerned about the trend that ... women are planning their pregnancies later and later," study author Jan-Peter de Bruin, MD, PhD, tells WebMD. "There's a very high proportion of women trying to get pregnant for the first time in their late 30s, and we know that fertility is decreasing [with older age]. ... So, we're looking for [indicators] that would indicate which women will have a decrease in fertility that starts earlier ... [to determine] which women will really have to plan their pregnancies early in life and who can postpone it a bit." Bruin is from the department of obstetrics and gynecology at the University Medical Center in Utrecht, the Netherlands.
In their study, Bruin and colleagues looked at health information collected on women who were past menopause and who were participating in a study on breast cancer. Among these women, 243 were sisters, 22 were non-identical twins, and 37 were identical twins. Using special statistical analyses, the researchers determined that the age at which the women reached menopause was about 70% to 87% determined by their genes. This research is published in the Aug. 30, 2001 issue of the journal Human Reproduction.
"It's very likely that the age at which your mother or sisters became menopausal will say something about your own menopausal age, but there's still a large variation," Bruin tells WebMD. "Right now, by looking at relatives, we can only determine the likely age at which a woman will reach menopause to within about six years.
"As soon as we're able to track down the genes [involved in menopause], we'll be able to narrow down that estimate ... [to] maybe two or three years," he says. "We can't prove this directly [yet], but we're pretty much convinced that menopausal age will be related to the age at which you will become sub-fertile and infertile."
"Is there a role for genes in premature or early menopause," asks expert Arie Birkenfeld, MD. "The answer is yes. ... That's been known for many, many years." He says he suspects that genes may affect the number of eggs a woman is born with and/or the number of eggs a woman uses up every month. Once all the eggs are gone, a woman has reached menopause.
"If your mother went through really early or premature [menopause], it has a lot of significance," Birkenfeld tells WebMD. "[You] should really consider having your children at an earlier age. ... You should also be aware of the fact that experiencing early menopause has its own medical consequences, like [increased risk of] cardiovascular complications and bone loss." Birkenfeld is co-director of the Diamond Institute for Infertility and Menopause in Millburn, N.J. and an associate professor of obstetrics and gynecology and reproductive medicine at the Mount Sinai School of Medicine in New York. He was not involved in the research.-->