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AMH levels vary during the menstrual cycle - Dr Sally Walder - 27th of June 2018


If you are reading this blog then the chances are that you’re considering having an AMH (Anti Mullerian Hormone) test. Perhaps your fertility consultant has asked you to have the test done before you begin IVF treatment. If you are in the UK you may have been told that your AMH levels will determine whether or not you qualify for IVF on the NHS.


AMH levels do not remain the same throughout your cycle!

Whatever your reason for taking the test it’s important to be aware that for most women AMH levels vary in a predictable pattern each month. The vast majority of medical professionals don’t share this information with the women they treat. Many of them are simply unaware of the pattern, and those that know about it are unlikely to tell you as:


‘Women whose AMH levels are ‘borderline’ may be able to access IVF by testing on their peak day when their AMH levels would otherwise fall short. Though these women may be able to fall pregnant using IVF they may require multiple cycles before succeeding, which would have a negative impact on the clinic’s ‘per cycle’ success rate.’


Here’s the pattern:

(Figure adapted from a journal article by Kissell et al. – reference given at the end of the post)

These are average figures taken from a large group of women with a wide range of ages - the highest AMH levels are observed in the middle of the follicular phase at about day 7. This is followed by a sharp drop in AMH level just prior to ovulation and a gradual increase throughout the luteal phase.


Do individual women’s AMH levels follow this trend?

The graph shows average AMH results for all 259 women tested – as a rule of thumb the older women had lower AMH levels than the average and the younger women had higher levels – the interesting thing is that most women’s AMH levels followed the pattern that the graph shows – a peak in the mid-follicular phase followed by a dip before ovulation.


Could this information help women to access IVF when they would otherwise have been ineligible?

In the UK, the minimum AMH level for women seeking NHS-funded IVF varies, but it is usually between 5 and 6 pMol/L. Women with relatively high AMH levels are likely to exceed this threshold even if they test just before ovulation when their AMH level is at its lowest, however, women whose AMH levels are ‘borderline’ may find that they are able to qualify by testing on day 7 whereas a test done on day 14 would have given an AMH level below the threshold.


How much does AMH actually vary within a cycle?

In the study mentioned above, the authors calculated the average of the maximum observed change in AMH within one cycle - for women aged between 35 and 44 the figure was 4.36pmol/L, fluctuations are greater in younger women (an average of 12.36 pmol/L for women aged 20 or less).

As an example, this means that a 36 year old woman might have an AMH test result of 3.2pmol/L if she took her test around ovulation time – however the same woman might have an AMH level of around 7.5pmol/L if the test was repeated on day 7 of her next cycle.


Is the pattern the same for everyone?

No. The researchers explain that for women with very low AMH they saw what they describe as an ‘aging ovary pattern’. For these women AMH levels fluctuate very little, remaining extremely low throughout the cycle. It is worth keeping in mind that though low AMH may be a barrier to IVF it is not necessarily going to prevent you from conceiving naturally – see my post on ‘Why test for AMH levels?’ for more info. 


To conclude…

Scheduling your AMH test for the middle of your follicular phase (around day 7 of a 28 day cycle) may give you a higher result than if you have the test later in your cycle. This could be crucial if you are hoping to have IVF treatment.


References:

1. Kissell KA, Danaher MR, Schisterman EF, et al. Biological variability in serum anti-Müllerian hormone throughout the menstrual cycle in ovulatory and sporadic anovulatory cycles in eumenorrheic women. Human Reproduction (Oxford, England). 2014;29(8):1764-1772. doi:10.1093/humrep/deu142.

2. Sowers M, McConnell D, Gast K, et al. Anti-Müllerian Hormone and Inhibin B Variability during Normal Menstrual Cycles. Fertility and sterility. 2010;94(4):1482-1486. doi:10.1016/j.fertnstert.2009.07.1674