Ovarian reserve testing has become ever more popular among women trying to gauge how many more years of fertility they have. However, a recent study published in the Journal of the American Medical Association has dampened the excitement among ovarian reserve enthusiasts and generated more than a little anxiety among women in general.

“The study came out and caused much concern and confusion among women,” says Mark P. Trolice, M.D., board-certified reproductive endocrinology, and infertility specialist and founder of Fertility CARE: The IVF Center. “It looked at ovarian age testing and the role that Follicle-Stimulating Hormone (FSH) or Anti-Mullerian Hormone (AMH) may play in determining their fertility.”

Below Dr. Trolice provides background about the two hormone tests and breaks down the study, its results, and whether FSH or AMH can indeed prove or predict your fertility.

What Is FSH?

Follicle stimulating hormone is secreted by the pituitary gland into the bloodstream. FSH is instrumental in the pubescent development and functioning of female ovaries and male testes. In women, the hormone encourages follicles in the ovary to grow before an egg gets released during ovulation. In men, FSH helps to stimulate sperm production in the testes (a process known as spermatogenesis).

“FSH has been the gold standard for many years of ovarian-age testing,” says Dr. Trolice. “FSH is a pituitary hormone used to stimulate the follicle that’s going to develop the egg and ovulate that month. The higher the level of FSH early in a menstrual cycle (usually measured on day 2,3 or 4), the lower the number of eggs. It’s indirectly being fed back by the ovary, and it’s giving a measure of the number of eggs.”

But Dr. Trolice notes that many infertility specialists have concluded that FSH testing is not a dependable way to predict a woman’s fertility. “FSH is not a very reliable test,” Dr. Trolice says. “(FSH levels) can fluctuate from month to month and the test is very limited because it has to be done on a certain day in the menstrual cycle. Also, the test has a number of false negatives: Even if an FSH level is normal, you could still have ovarian aging that wasn’t detected that month.”

What Is AMH?

Anti-mullerian hormone is a protein manufactured by the cells in a woman’s growing follicles that surround every egg. AMH levels decrease as a woman gets older with the number of visible and microscopic follicles dropping steadily. By menopause, AMH levels and follicle count are practically non-existent.

“AMH is the test we use exclusively at Fertility CARE, and most reproductive centers have stopped using FSH and now test only with AMH,” says Dr. Trolice. “AMH is a hormone produced in the cells surrounding the egg. Therefore, the lower the number of eggs, the lower the AMH, and the higher the ovarian aging.”

AMH testing, until recently, was primarily used for female infertility patients before beginning in vitro fertilization (IVF) treatment. AMH levels can help predict how the ovaries will respond to IVF stimulation medication and indicate the chances for IVF success.

Many infertility doctors took this a step further, claiming that the level of AMH in a healthy woman’s blood can predict whether or not she will have infertility problems in the future.

“Anti-Müllerian hormone is made by the tiny liquid capsule-like follicles in the ovaries, that house and nourish human eggs,” says Dr. Trolice. “By calculating the amount of AMH the follicles produce, it is thought, fertility specialists can measure the remaining number of eggs a woman has left.”

What Do the FSH and AMH Tests Accurately Reflect?

“Can the FSH and AMH tests predict fertility?” asks Dr. Trolice.

“The University of North Carolina study published in the Journal of the American Medical Association looked at women between the ages of 30 and 44, who had lower levels of AMH and FSH. They compared that group to women of the same age with normal FSH and AMH levels,” says Dr. Trolice. “The study looked at whether it was able to predict their fertility in terms of pregnancy rates. And there was no difference in pregnancy rates between the two.”

“But there are certain caveats though,” says Dr. Trolice. “First off, they did not include any fertility problems either in the man or the woman. Second, they did not include patients who had subsequent use of fertility medication, so we do not know if that was included (we call that censored information). And third, the pregnancy tests were just the positive pregnancy tests. They didn’t talk about ongoing pregnancies or live birth. We don’t know if low AMH or high FSH would have resulted in a higher rate of miscarriage.”

The Bottom Line

Dr. Trolice is hesitant to put too much weight behind the FSH and AMH tests, especially for women who haven’t started trying to conceive or who have only recently begun their attempts to have a baby.

“Unless you’ve been trying for an adequate time to conceive, I think getting tested for AMH or FSH levels is premature,” he says. “The younger you are, irrespective of these test results, you should still have success because you still have good quality eggs.”