The Anti-Mullerian hormone is often regarded as a test which looks at the quality of eggs. Infact there is increasing evidence that AMH may not be a quality of eggs, but more a quality of numbers of small pre-antral follicles (small eggs in the ovary).
In earlier studies in the United States, the level of AMH did not prevent women from getting pregnant naturally. It seemed to be all age dependent. Age tends to be the most important factor. AMH does tell us about the number of eggs which remain, and its decline may tell us about how the ovaries’ eggs have started to decline. Other than that, except at very low levels, it does not seem to tell us hugely about what quality of eggs would be available.
There is no doubt that in IVF you require more numbers, and a low AMH may limit the number of eggs that may be available for IVF. A study published in 2019 in the RBM online looked at live birth rates in modified natural IVF, with women with very low AMH levels; 638 cycles were evaluated and there was no doubt that there was a weak correlation of AMH with live birth rates. Thus in this study, they used a modified natural cycle, where they added a small amount of FSH injections, an antagonist was added to block ovulation, and Indomethacin was given to lower the chance of eggs being released.
They looked at the live birth rates per cycle and it was between 11.6 per cent for a very low AMH to 17 per cent for a high AMH, and with a normal AMH it was 12.6 per cent. Per transfer again, chances of pregnancy remain very much stable. Cancellation rates were almost similar in all the three cycles, thus while AMH concentrations were a reliable marker of mild and natural IVF, its role in achieving a pregnancy in a natural cycle is limited and at present we feel that it is still very early to label women with a very low AMH as being infertile and having a lower chance of pregnancy, while pregnancy seems to be age-related. Some women tend to have a slightly better antral follicular count and may stand a better chance of pregnancy.