Low AMH and Egg Quality: What an FMR1 IVF Study Found

By Seungjoo Lee

Low AMH and egg quality are related concerns, but they are not interchangeable. In an IVF study of FMR1 premutation carriers, fewer eggs were retrieved, yet the chromosome-normal rate per biopsied blastocyst was not lower than in matched controls. Maternal age was more closely associated with obtaining at least one euploid embryo than AMH was.

Fewer eggs do not automatically mean poorer chromosome outcomes for every embryo. These findings concern a specific genetic group, not all women with low AMH.

For a woman preparing for in vitro fertilization, hearing that her AMH is low often prompts an immediate worry: if only a few eggs can be retrieved, must those eggs also be of poor quality?

It can seem natural to assume that fewer eggs mean greater difficulty making good embryos and a lower chance that an embryo will have a normal chromosome count. However, a recent study suggests that producing fewer eggs and having poorer chromosome outcomes in the embryos made from them are not necessarily the same problem.

The study was published online in Fertility and Sterility on September 22, 2026.

The number of eggs was clearly lower

The researchers studied women with a premutation in a gene called FMR1.

Some women with this genetic change experience a decline in ovarian function earlier than their peers. Their AMH may be lower, and ovarian stimulation for IVF may yield fewer eggs.

The investigators analyzed 173 IVF/ICSI cycles in FMR1 premutation carriers. As expected, the carriers had lower AMH and fewer eggs retrieved. They also produced fewer mature eggs, normally fertilized eggs and usable blastocysts.

In other words, they started IVF with fewer eggs available. But when the researchers examined the chromosome outcomes of the embryos that developed, the picture was different.

Fewer eggs did not mean a lower euploidy rate per tested embryo

The researchers separately compared cycles involving preimplantation genetic testing for aneuploidy, or PGT-A.

They matched FMR1 premutation carriers with non-carriers of similar age, body mass index and egg yield, then examined chromosome outcomes in the resulting embryos. There was no significant difference in the per-embryo euploidy rate.

The women with an FMR1 premutation produced fewer eggs. But among the embryos that had reached the blastocyst stage and were biopsied, each embryo was not less likely to have a normal chromosome count.

This is the distinction that makes the study interesting.

A woman who produces 10 eggs and a woman who produces three do not begin with the same number of opportunities. More eggs generally provide more chances to make fertilized eggs and blastocysts, and therefore more opportunities to obtain a euploid embryo.

With fewer eggs, the number of opportunities is smaller. That does not establish that each hard-won egg is itself a poor-quality egg.

Age mattered more than AMH for obtaining a euploid embryo

Another notable finding concerned the chance of obtaining at least one embryo with a normal chromosome count.

In the analysis, advancing maternal age was associated with lower odds of obtaining at least one euploid embryo, whereas AMH did not show an independent association with that outcome.

AMH is primarily a marker used to estimate ovarian reserve and likely ovarian response. A low AMH result therefore suggests that fewer eggs may be obtained during stimulation.

Embryo chromosome abnormalities, by contrast, are closely related to maternal age. The study’s message is that a low AMH result should not automatically be interpreted as proof that a woman’s eggs are also of poor quality.

Why this cannot be generalized to every woman with low AMH

Important limits remain. This was not a study of all women with low AMH. It focused on a particular genetic group: women carrying an FMR1 premutation.

Nor did the study demonstrate that every aspect of embryo quality was normal. It found no reduction in the chromosome-normal rate among blastocysts that reached biopsy and underwent PGT-A.

That does not mean that implantation, pregnancy and live birth were all identical. It also does not address every non-chromosomal factor that can influence an embryo’s developmental potential.

Even with those limits, the central distinction is useful: having fewer eggs and having eggs with poorer chromosome potential are not the same statement.

Women with FMR1-associated diminished ovarian reserve obtained fewer eggs during IVF. However, the embryos that successfully reached the biopsied blastocyst stage did not show a lower per-embryo likelihood of euploidy in the matched comparison.

One AMH number should therefore not be used to dismiss the potential of the eggs that may still be obtained.

Study source, sample size and design

The study, FMR1-Associated Diminished Ovarian Reserve: Reduced Oocyte Yield Without Loss of Per-Embryo Ploidy, was conducted by researchers affiliated with Melbourne IVF, the University of Melbourne, Boston IVF and Yale University School of Medicine, among others. It was published online in Fertility and Sterility on September 22, 2026. DOI: 10.1016/j.fertnstert.2026.09.010; PMID: 42772432.

This was a retrospective cohort study. Of the 173 carrier cycles, 142 underwent PGT; 124 had at least one blastocyst biopsied. The PGT-A matched analysis compared 33 carrier cycles with 33 non-carrier cycles selected from 5,376 potential controls.

The per-embryo euploidy rate ratio was 1.01 (95% confidence interval 0.82–1.25; P=0.91), consistent with no demonstrated difference rather than proof that the groups were identical. The results are limited to clinically identified, PGT-A-eligible carriers and biopsied blastocysts. They should not be extended to unscreened carriers, other causes of diminished ovarian reserve or non-chromosomal embryo competence.