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 shut down and the male (Woolfian) ducts to survive – hence the term anti-Müllerian hormone. The Woolfian ducts are then free to develop into different parts of the testes: the epididymus, the vas deferens and the seminal vesicles. In a female foetus (XX chromosomes) the Woolfian ducts shut down 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 is important in the early stages of development of the follicles. These are eggs surrounded by one or more layers of cells.
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 foetus does not produce enough anti-Müllerian hormone, the Müllerian ducts do not shut down and this leads to persistent Müllerian duct syndrome. Patients with this syndrome will have a male appearance but they usually have undescended testes (cryptchordism) and low or absent sperm count due to abnormal development of the Woolfian duct. This leads to malformation of the vas deferens and epididymus. This condition is rare.
Measuring levels of anti-Müllerian hormone can be used as a predictor of ovarian reserve in women, in other words how many follicles are left in the ovaries. In women anti-Müllerian hormone levels peak at around puberty and remain relatively constant until after the menopause, when no follicles remain, and levels of anti-Müllerian hormone become low. Levels of anti-Müllerian hormone are also low in women who undergo premature ovarian failure, so measuring anti-Müllerian hormone could be used to predict whether a woman is undergoing premature ovarian failure.
High levels of anti-Müllerian hormone may be associated with polycystic ovarian syndrome. However, measuring anti-Müllerian hormone can be misleading and does not give a definitive diagnosis of either premature ovarian failure or polycystic ovarian syndrome. It is important that any test to measure anti-Müllerian hormone levels is carried out by a qualified medical professional.
Written: July 2012. Review due: July 2014