Oct. 25, 2006 - Twins may be up to five times more likely to experience premature menopause than other women, according to a new study.
Researchers studied more than 800 identical and non-identical female pairs of twins and found the women were three to five times more likely to experience premature menopause by either age 40 or 45, compared with other women.
Premature ovarian failure (POF) occurs when the ovaries stop working before the age of 40, which causes premature menopause. It is a rare condition that usually affects about one in 100 women.
"The reason that the association between twins and POF has been largely overlooked up to now is probably because POF is still uncommon, even in twins (3 to 5 in a hundred)," says researcher Roger Gosden, MD, professor of reproductive biology at Weill Medical College of Cornell University in New York, in a news release.
Although premature ovarian failure is rare, researchers say the increased risk of premature menopause among twins is significant and could affect decisions about delaying.
Twins at Risk of Premature Menopause
In the study, published in Human Reproduction, researchers measured the prevalence of premature ovarian failure among 832 twin pairs registered in Australian and U.K. databases. Then, they compared it with the prevalence among a comparison group of more than 3,400 Dutch women.
The results showed that premature menopause was three to five times more common among twins than other women, when measured at ages 40 and 45.
Researchers say the study confirms previous findings of a higher risk of premature ovarian failure among non-identical twins, but it is the first to show a similar risk among identical twins.
Gosden says the reasons for a higher risk of premature menopause among identical and non-identical twins appear to be very different and require further research.
"It may be that, contrary to the usual situation of non-identical twins being more common in women past the prime age of(20s) -- in mothers whose biological clock is running faster than normal and whose ovarian reserve is running low -- the likelihood of having twins [in general] shifts to an earlier age -- to their peak childbearing years," says Gosden.
"So, even though they are non-identical, one or both twins born to these mothers may be inheriting her tendency to early menopause," he says.
Infertility Options Now Available
Gosden says the vast majority of twins can expect to reach menopause at a normal age.
But for both identical and non-identical twins with premature ovarian failure and a sibling who is still fertile, there are options to treat infertility such as egg donation or ovarian tissue transplant.
"For identical twins, in addition, we now have the possibility of ovarian tissue grafting. That might even be considered in some rare cases for non-identical twins if there is a good tissue match," says Gosden.