If you do, wait and see. Researchers have developed a blood test they say can predict how long of a reproductive life a woman has before menopause.
The blood test measures levels of a hormone called anti-Mullerian Hormone (AMH), which is produced by the cells in women’s ovaries and is a marker for ovarian function. The test could tell women as young as 20 when they would enter menopause. Sixty-three women reached menopause during the course of the study, and the test was able in most cases to predict the age within about four months of the woman’s actual age; the maximum margin of error was between three and four years.
The AMH is a hormone produced by the granulosa cells of the early developing antral follicles. These are the immature eggs that wake up from their dormant state and develop into mature eggs. As a woman runs out of eggs, the number of these small antral follicles decline in number and as a result the serum Anti-Mullerian hormone falls. This is why serum Anti-Mullerian hormone testing is a good estimate of residual egg number.
Study author Fahimeh Ramezani Tehrani, president of the Reproductive Endocrinology Department of the Endocrine Research Centre and a faculty member and associate professor of Shahid Beheshti University of Medical Sciences in Tehran, Iran, reported her findings at the European Society of Human Reproduction and Embryology in Rome.
The findings could have implications on how women approach family planning. Researchers said it is one of the first population-based studies to provide a statistical model for predicting age at menopause.
Much of the hubbub surrounds the test's implications: If a woman knew when her childbearing years would end, she could take better charge of her reproductive destiny. Perhaps she would get pregnant earlier—or freeze her eggs in her late 20s—if she knew menopause was going to strike at, say, 41 instead of the average age of 51. Or she might stay off the mommy track a bit longer if her fertility was going to last until 57.
“We developed a statistical model for estimating the age at menopause from a single measurement of AMH concentration in serum from blood samples,” Ramezani Tehrani says. “Using this model, we estimated mean average ages at menopause for women at different time points in their reproductive life span from varying levels of serum AMH concentration. We were able to show that there was a good level of agreement between ages at menopause estimated by our model and the actual age at menopause for a subgroup of 63 women who reached menopause during the study.”
Predicting Menopause with a Blood Test
The study results are based on blood samples from 266 women aged 20 to 49 who were part of the larger Tehran Lipid and Glucose Study, which began in 1998 and continues today. Blood samples were repeatedly collected from the study participants every three years, and the researchers also collected data about the women’s socioeconomic backgrounds and reproductive histories. The average age of beginning menopause was about 52.
Ramezani Tehrani and her team found that:
- AMH levels of 4.1 ng/mL or less predicted early menopause (before age 45) in 20-year-olds
- AMH levels of 3.3 ng/mL predicted early menopause in 25-year-olds
- AMH levels of 2.4 ng/mL predicted early menopause in 30-year-olds
Women who had AMH levels of at least 4.5 ng/mL at age 20, 3.8 ngl/mL at age 25, and 2.9 ng/mL at age 30 could expect menopause to begin after they turned 50.
“The results from our study could enable us to make a more realistic assessment of women's reproductive status many years before they reach menopause,” says Ramezani Tehrani. “For example, if a 20-year-old woman has a concentration of serum AMH of 2.8 ng/mL, we estimate that she will become menopausal between 35-38 years old.”
Ramezani Tehrani says more studies are needed to validate these findings, but the blood test could be an important diagnostic tool to evaluate one’s reproductive life and could provide a more accurate response than chronological age.
William Ledger, a fertility expert at the University of Sheffield in England, who was not involved with the research, told the Associated Press: “This is not something we could start rolling out tomorrow. But if it really does work, it could be immensely useful to young women who are making choices about whether to work or have a family.”
Some experts, however, say the menopause test is still far away from being used in clinical practice. That's partly because of some uncertainty in determining standard levels of this hormone and whether these levels vary from woman to woman. For example, no one knows yet whether levels of AMH differ among racial and ethnic populations. Perhaps a low level in an Iranian woman is in the normal range for an African-American. Previous studies have also shown that obese women tend to have lower levels than women of normal weight, though they may not go into menopause any earlier.
Still, the AMH test has so far proven useful in clinical practice for predicting the success of certain infertility procedures, like in vitro fertilization. (A higher level means more eggs are likely to be retrieved from the ovary, though it doesn't seem to predict the quality of the eggs.) Ovarian cancer patients may also undergo the test to determine whether chemotherapy has affected their fertility.
But whether this hormone test will eventually be widely used to pinpoint the age of menopause remains a big unknown. If it does prove predictive, many women will no doubt be eager to learn just how long their biological clocks will keep on ticking.
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