SUMMER REPLAY: Can fertility tests help you safely delay motherhood?

A study looks at whether "fertility testing" can predict the future.

This item was originally published in HeyReprotech on 24 Jan 2023.

I still remember when I first paid attention to the words anti-Mullerian hormone (AMH). It was 13 years ago and I was interviewing a young woman who was donating eggs to two gay friends. She had learned that her number was worryingly low.

A low number meant a low number of eggs and, it was presumed, low fertility.

She was 23 years old.

There were many awful details wrapped up with this news.

One was how she found out. The doctor had told the recipients, but he had not bothered to tell her. The recipients delivered the punch.

Later, when she confronted the fertility doctor, he casually advised her that she "shouldn't wait" until she was in her thirties if she wanted kids. She hadn't started planning for a family, but now it suddenly felt in jeopardy.

She didn't produce a lot of eggs. Then the surrogate had a miscarriage. At that point, the egg donor decided not to continue.

I'm not in touch with her anymore, but I wonder how that AMH result affected her choices as she moved forward in life.

There has been a lot of controversy about AMH and other hormones as predictors of fertility, even as they continue to be sold and marketed as such. Women who are considering delaying motherhood are often advised to "test their fertility" before deciding what to do.

But should they? Do these tests tell women what they need to know?

A paper out in Fertility and Sterility says no.

4 minute read

Women are well-acquainted with the apocalyptic decline of their egg supply: born with over a million, by puberty they have just 400,000, and by menopause only a few thousand. But in between those last two milestones, how does a person know if there's time to wait?

Often, these days, they turn to so-called fertility tests, which sample hormones. Test results appear to correlate with numbers of eggs available for retrievals in IVF, for instance, or in roughly estimating when menopause might come along. So it was assumed that they could predict chances of actually having a baby too.

But can they?

Anne Steiner, at Duke Fertility Center, in North Carolina, and her colleagues, wanted to know if commonly used fertility tests were able to predict a woman's current chances of getting pregnant. They called it the Time To Conceive (TTC) study.

Between 2008 and 2015, the researchers recruited 750 women who were aged 30 to 44, living with a male partner, had no known infertility, and had just started trying for a baby.

The participants provided blood and urine samples at the start, which were used to assess their levels of anti-Mullerian hormone (AMH), follicle-stimulating hormone (FSH) and early follicular phase inhibin-B. These hormones are often used as an indirect way to measure the size of the ovarian reserve — essentially how many eggs a woman still has in the vault. The assumption is that more is better.

The researchers followed the women for a year as they tried to conceive. The women filled out questionnaires daily and monthly, recording information about medications, bleeding, sexual intercourse, and, of course, pregnancy, for which they tested regularly.

When the analysis was complete, however, the researchers were surprised. The hormone tests did not predict how likely a woman was to get pregnant. They published their results in 2017.

Steiner wondered if the time frame had been too short. She also thought it might be better to measure live birth rather than just conception, because the capacity to reproduce includes not just conceiving but carrying through fetal development, and diminished ovarian reserve might somehow affect success with the latter. Would those same tests predict the women's future reproductive outcomes?

She and her new research team contacted women from the original TTC cohort about a follow up study, and 336 women agreed to take part. Between late 2020 and early 2021, the participants filled out a questionnaire about how many children they'd had, how long it had taken them to get pregnant and whether they'd been diagnosed with infertility.

There had been 239 pregnancies, resulting in 225 live births and 14 losses. Seventy-three women met the criteria for infertility.

But to the surprise of the researchers, the hormone levels in the tests did not predict these outcomes either. Some 79 percent of the women with low AMH, which indicates a low ovarian reserve, went on to give birth, for instance, compared to 71 percent of women with normal AMH levels. "The probability of live birth did not differ for women with low AMH," the authors write. "Similarly, the probability of live birth did not differ for women with high FSH levels compared to women with normal values." There was also no higher risk of future infertility, they found.

In a paper in the journal Fertility and Sterility, the authors write that "diminished ovarian reserve is not associated with reduced future reproductive capacity."

The finding is important because tests like these are common (and expensive) and many women make decisions based on their results. A woman might decide to try right away, delay for a decade, or put some eggs on ice. Indeed, some of the companies selling these tests are in the business of selling treatments such as egg freezing as well.

The authors conclude that women should be "cautioned" about using biomarkers of ovarian reserve as predictors of their future reproductive capacity. Steiner hopes that women will stop taking the tests for this purpose, that physicians will stop ordering them and that companies will stop marketing them.

The decline in fertility, says Steiner, is not related to the quantity of eggs, but rather to the quality. And these tests don't measure that.

Harris et al. "Markers of ovarian reserve as predictors of future fertility." Fertility and Sterility. 2023.

Steiner et al. "Association between biomarkers of ovarian reserve and infertility among older reproductive age women." JAMA. 2017.

Update: We’re still talking about this:

Melissa Davey. "Widely advertised hormone test unreliable as fertility prediction tool for women, researchers say." The Guardian. 28 Jul 2024.