Fertility: Predicting the Exact Age of Menopause

Nancy Caspell thinks she can have it all. At age 28, she isn't ready for children. Even though she's not in a serious relationship, she figures by the time she hits age 35 or 40 she'll have met the man of her dreams, be more established in her career and, as with all happy endings, finally be ready for pregnancies and kids.

She only hopes her ovaries agree.

"I don't want to be one of those women who find out too late that my eggs are fried and the only thing I have to look forward to is wrinkles," says Caspell, a sales rep from Cleveland. "But I think my biological clock will keep ticking for a while."

With any luck it will. But it may not be ticking as long as Caspell hopes. Too many women, say doctors, assume their biological clock will run full-tilt well into their 40s. And despite medical advances in women's health, there is still no good early-warning test to determine exactly when a woman will go through menopause and her biological clock will run out. Most women go through menopause between the ages of 45 and 55, but it can happen anytime between 40 and 60. That's a big span. And for women who may be destined to go through menopause on the early side, finding out that they're not as fertile as they thought they'd be in their late 30s can be a heartbreaking surprise.

But now researchers in the Netherlands think they may have found a way to give women more warning—and it has nothing to do with age, but rather with an ovarian hormone called AMH. In a study to be published in the June issue of the Journal of Clinical Endocrinology & Metabolism, researchers from the University Medical Center Utrecht say that anti-Mullerian hormone, or AMH, is actually a better predictor of a woman's reproductive age than chronological age. AMH is a marker of what doctors call ovarian reserve, which is related to the quality and number of eggs in the ovaries and how well the ovarian follicles, tiny sacs in which eggs mature, respond to hormones.

In their study the researchers looked at the AMH levels in a group of 144 healthy, fertile women ages 25 to 46. Using that information and the results of a reproductive history survey of older women between 50 and 70, they created a data model that can predict, they say, when a woman will go through menopause within a few years.

Currently the rule of thumb is that most women go through menopause at about the same time as their mothers. But there are variations. Once women hit about 45 and start experiencing erratic periods or hot flashes, "it's not brain surgery" to figure out the woman is well on her way to the menopause, says Dr. Wulf Utian, executive director of the North American Menopause Society.

But for women younger than 45, diagnosis can be a little trickier. Hormone tests, such as the follicle-stimulating hormone or FSH test, may be used when a woman younger than age 45 experiences symptoms such as erratic periods or hot flashes. But FSH levels can fluctuate daily, which can complicate a diagnosis.

The new AMH model could improve predictions to "plus or minus one to two years," says lead author Dr. Jeroen van Disseldorp. And it would be most appropriate for women who are 30 years old, since AMH levels seem to rise until the third decade of life—the point when many women may be making decisions about whether to postpone pregnancy in favor of a career, van Disseldorp says.

Though the AMH research is in its early stages and results have to be validated in different populations, knowing how long a woman's biological clock will keep running would be important information. "Everyone is looking for a marker as to when menopause will happen, not when it's [already] happened," says Utian. "This [AMH] test isn't ready for prime time, but it could be beneficial." For one thing, it might get women to pay closer attention to heart and bone health earlier in life: menopause brings with it an increased risk of osteoporosis and heart disease. But the big payoff, of course, would be in helping predict or avert fertility problems.

The biological reality is that eggs don't stay fertile forever. Women are born with about 1 million eggs in their ovaries. At age 20 the average woman has about 200,000 eggs. By age 40 that number has dropped to less than 20,000. Egg quality starts to decline at about age 30, takes a sharp drop at about age 35, and by about age 40 almost half of all women are not able to have a baby naturally, says Dr. David Adamson, president of the American Society for Reproductive Medicine.

Despite advances in assisted reproductive technologies, the optimal time for a woman to get pregnant is before age 35. "Don't shoot the messenger, but that's a reality, and it's one that some women who want children don't want to hear," says Adamson. "Eggs deteriorate. You can't take reproduction for granted."

Elyse Ranart, 46, a fashion editor from Ft. Lauderdale, Fla., knows that scenario all too well. Single and hearing her bio-clock ticking, she started thinking about having a child in her late 30s. Her FSH values were normal, but her doctors encouraged her to "make a decision," she says. "But I figured I had more time." By her early 40s she was finally ready to have a child, only to discover that her "eggs were crap," says Ranart, who started experiencing hot flashes and erratic periods within the last few years, too. "My generation was all about career and control. I found out too late that I can't control biology."

Still, knowing too much about your biological clock might present its own problems, perhaps adding to the pressure on women to find a partner. "There have been many bad relationship decisions based on the biological clock," says psychologist Laura Berman, director of the Berman Center in Chicago, Ill.

There's also the question of what menopause means. For many women menopause is simple biology, the time of life when menses have stopped. For others, though, it can be a time of strong emotion coupled with some difficult physical symptoms. Either way, it's a phase that women might like a little more warning about—especially if menopause is arriving earlier than they expected based on their age or maternal history. "Menopause is linked to femininity and vibrancy, and some women question whether their lives as women, real women, are over," says Berman.

For Ruth Lloyd, who went through menopause at age 43, the emotions were as tough to deal with as menopause's calling cards: hot flashes, brain fog and body changes, which came much too early for her liking. "I was young and healthy and then I felt scared and ancient," says Lloyd. "No one is supposed to go through menopause at age 43, or so I thought. Now I know different."

Ranart and Lloyd say they would welcome a test that could better gauge the onset of menopause. "Bring it on," says Ranart. "If nothing else, it might save some other woman from thinking that hope springs eternal."

Still, she also wants women to know that a woman's life doesn't end once her fertility passes. "I'm in shape, I still turn heads, and I feel pretty good about myself," Ranart says. And in a few months one of her wishes will finally come true. She is in the process of adopting from abroad and expects the relationship to be finalized this summer. "I'm going to be a mom," Ranart says. Which proves again that biology doesn't have to be destiny.