Anti-Müllerian hormone

Anti-Müllerian hormone is a protein hormone which is important in the development of the reproductive tract in a male foetus and is also produced (before birth) by the testes and ovaries.

Alternative names for anti-Müllerian hormone

AMH; Müllerian inhibiting factor; MIF; Müllerian-inhibiting hormone; MIH; Müllerian-inhibiting substance; MIS

What is anti-Müllerian hormone?

About eight weeks after conception the human foetus has two sets of ducts, one of which can develop into the male reproductive tract and the other into the female reproductive tract. If the foetus is genetically male (XY chromosomes) then the embryonic testes will produce anti-Müllerian hormone. This causes the Müllerian (female) ducts to disappear – hence the term anti-Müllerian hormone, whilst testosterone produced by the testes causes the male (Wollfian) ducts to survive. The Wollfian ducts go on to develop into the different parts of the male reproductive system: the epididymis, the vas deferens, the seminal vesicles and the prostate gland. In a female fetus (XX chromosomes) the Wollfian ducts disappear (because of the lack of testosterone) and the Müllerian ducts develop into the fallopian tubes, uterus (womb), cervix and the upper part of the vagina.

Anti-Müllerian hormone may also have a role in regulating sex steroid production in puberty and in the adult ovaries and testes. In the ovaries, anti-Müllerian hormone appears to be important in the early stages of development of the follicles, which contain and support the eggs prior to fertilisation. The more ovarian follicles a woman has, the more anti-Müllerian hormone her ovaries can produce, and so AMH can be measured in the bloodstream to assess how many follicles a woman has left in her ovaries: her ‘ovarian reserve’.   

How is anti-Müllerian hormone controlled?

It is not currently known how the production of anti-Müllerian hormone is controlled.

What happens if I have too much or too little anti-Müllerian hormone?

When the male fetus does not produce enough anti-Müllerian hormone, the Müllerian ducts do not disappear and this leads to persistent Müllerian duct syndrome. Patients with this syndrome will have a male appearance but they usually have undescended testes (cryptorchidism) and low or absent sperm count due to abnormal development of the Wollfian duct. This can be associated with malformation of the vas deferens and epididymis. This condition is rare.

Since ovarian follicles produce anti-Müllerian hormone in adulthood, measuring the levels of anti-Müllerian hormone in blood provides a way of estimating ovarian reserve in women. Consequently, anti-Müllerian hormone levels are routinely used to predict how well a woman is likely to respond to ovarian stimulation for in vitro fertilisation (IVF) fertility treatment, and what doses of hormones should be used during IVF.

In women anti-Müllerian hormone levels peak around puberty and remain relatively constant until after the menopause, when no follicles remain, and levels of anti-Müllerian hormone become low. Some studies suggest that levels of anti-Müllerian hormone may be lower than normal in women who undergo premature ovarian failure. However, anti-Müllerian hormone results need to be interpreted with caution since many other factors can affect an individual’s fertility.

High levels of anti-Müllerian hormone may be associated with polycystic ovary syndrome. However, measuring anti-Müllerian hormone can be misleading and does not give a definitive diagnosis of either premature ovarian failure or polycystic ovary syndrome. It is important that any test to measure anti-Müllerian hormone levels is carried out by a qualified medical professional.

Last reviewed: Mar 2018