Since a considerable proportion of subfertility is due to postponement of childbearing, measurement of ovarian reserve is of interest to women in general. AMH is becoming increasingly used in General, Oncology and Assisted Reproduction Practice. Assessment of ovarian reserve may provide insight into the remaining number of fertile years a woman has or may predict ovarian reserve prior to IVF treatment.
Ovarian reserve decreases in pre-menopausal women as the quality and number of ovarian follicles decline with age, resulting in the decrease of a woman’s reproductive function. AMH is a hormone marker for quantitative prediction of ovarian reserve, ovarian aging, ovarian dysfunction and ovarian responsiveness.
AMH levels correlate with the number of antral follicles. Women with lower AMH and antral follicular counts produce a significantly lower number of oocytes compared with women with higher levels. Fertilisation rates in women with lower AMH levels would seem significantly inferior compared with women with higher AMH levels, irrespective of the method used to achieve assisted fertilisation. Women with low AMH levels have fewer oocytes, have lower fertilisation rates, generate fewer embryos, and have a higher incidence of miscarriage during fresh transfers, ultimately culminating in a halving of the pregnancy rate per IVF cycle compared with women with high AMH levels***. When compared to using FSH and age, AMH acts as a superior predictor of live birth and anticipated oocyte yield.
AMH levels cannot measure the actual number of oocytes, but it strongly correlates with the size of the ovarian follicle pool. With AMH, clinicians have a reliable serum marker of ovarian response that can be measured independently of the day of the menstrual cycle (as opposed to FSH and Inhibin B which must be taken on Day 3) and which does not correlate with lifestyle factors (smoking, body mass index, alcohol consumption, ethnic origin, chronological age), or reproductive history (age at menarche, years since menarche and gravidity)****. Findings such as premature ovarian failure can be effectively diagnosed by unexpectedly low AMH levels and in instances of Polycystic Ovary Syndrome (PCOS), a well recognised endocrine disorder in women of reproductive age, a two or three fold increase in the number of growing follicles would be reflected in a two or three fold increase in the serum AMH levels.
It would seem that serum AMH is one of the best hormone markers to assess the quantitative aspect of ovarian reserve or dysfunction* Measuring AMH cannot predict whether a woman is able to become pregnant – there are other important factors that have to be taken into account – lifestyle, infection, genetic abnormality, quality of sperm and other male factors – but it is considered the best hormone to date to identify her potential reproductive capacity.
* Fertil Steril. 2005; 83(4):979-87 (ISSN: 1556-5653)** Hum Reprod. 2007 Mar;22(3)
*** Human Reproduction 2007 22(9):2414-2421; doi:10.1093/humrep/dem204
**** Reprod Biomed Online. 2007 May;14(5):602-10/Fertil Steril. 2007 Jan;87(1):223-6.