Technique measures a woman's 'biological clock'

Photo by miamiamia
A technique has been developed by scientists to tell a woman how fast her biological clock is ticking and when menopause is likely to hit.

Sandy Martinez, a 30-year-old manager of actors, is busy building a career, but she also wants to raise a family.

She wonders how long she can put it off. "Obviously your body's not the same when you're older, so that is a concern to me," she told CTV News.

"A woman of say, 30 or 32, who's thinking about whether to press on with her career, or wants to get into a better financial situation to have a family, could be rest assured they have more time," said Dr. Hamish Wallace, one of the study's authors.

"What we have done is to come up with a method that may allow us to predict for a woman what ovarian reserves she has and at what age she is likely to experience the menopause," Wallace, a pediatric oncologist and lecturer at the University of Edinburgh, told Reuters.

The Scottish scientists say they can do this by measuring the volume of a woman's ovaries using ultrasound.

This could also tell them how many eggs a woman has left, which could have a significant impact on fertility treatments.

"The ultrasound measurement is taken to work out the volume of the ovaries. If the ovaries are larger than average for her age, then she is likely to have a later menopause and if they are smaller she is likely to have an earlier one. Essentially we try to quantify by how much, by how many years," Dr. Thomas Kelsey, a computer scientists at the University of St. Andrews, told Reuters.

Women start with an estimated 800,000 eggs, but that number declines over time.

By the time a woman reaches 37, she's down to about 25,000 eggs. At that time, the rate of decline speeds up. The ovaries shrink until almost all the eggs are depleted. At that point, menopause occurs.

That generally happens at age 50, but can happen between the ages of 42 and 58.

Wallace and Kelsey reported their findings in the medical journal Human Reproduction.

"It is going to be useful for couples who have fertility problems because it is an easy way for the fertility clinics to work out essentially whether it is worth doing IVF (in-vitro fertilization) or whatever treatment," Kelsey said.

For example, a woman with a number of fertile years ahead might be better off trying to conceive naturally or to space out fertility treatments, he said.

Conversely, if the egg supply is low, it might not be worth it, he said.

Two instances in which the diagnostic method won't work is for women taking oral contraceptives or those suffering from polycystic ovarian syndrome, which causes infertility.

The scientists are planning to do longer-term studies to track young women until they hit menopause.

"It opens the door to the possibility of screening women for early ovarian aging. These women may be at increased risk to their general health from the effects of having an early menopause," Wallace said.

But some warn against the use of this technique by perfectly healthy women.

"The difficulty of getting pregnant goes up as you get old. And the risk of miscarriage or Down's Syndrome goes up as well. So it's not just how many eggs you've got," Diane Allen of the Infertility Network.

Study: Ovarian reserve and reproductive age may be determined from measurement of ovarian volume by transvaginal sonography

Source: http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20040617/fertility_study_040617?s_name=&no_ads=

Category: biological clock, early menopause, menopause, ovarian reserve, ovaries, ultrasound