Anti Mullerian Hormone

It is also known as Mullerian Inhibiting Factor (MIF), or Mullerian Inhibiting Hormone (MIH), or Malaria Inhibiting Substance (MIS). Anti Mullerian hormone is a protein that is important for the development of the reproductive tract in the male foetus. It is produced by reproductive tissues, before birth, by testes in males and ovaries in females. The role of AMH and the amount normally present varies upon sex and age. The AMH plays a vital part in sexual differentiation in the foetus.

Role of AMH

Before birth, AMH is made in the foetus testis and ovary. Around the 7th week after the conception of the foetus has both Mullerian (female) and Wolffian (male) ducts, which can develop either into the male or female reproductive system. If the foetus has XY or male chromosomes, the testes will produce AMH and the Mullerian ducts will disappear. If the foetus has XX or female chromosomes a lack of testosterone will cause the Wolffian duct to vanish and the Mullerian duct will develop into a female reproductive system.

AMH has a role in puberty and it helps in the early development of follicles. AMH levels can be measured to determine how many follicles women have in their ovaries.

Significance of AMH

• If a sufficient amount of AMH is not available or absent during the process of development of the foetus, then both male and female organs may develop.

• AMH may be more produced in some ovarian tumours and thus tests can be used to identify tumors in the ovaries.

• High AMH levels are also associated with polycystic ovary syndrome PCOS. The excess follicle in PCOS results in the production of a large amount of AMH.

• The level of AMH is useful in identifying the egg reserve and chances of conceiving in females.

• AMH is no longer produced when follicles degenerate or approach menopause. The level of AMH is used to identify the fertility status or menopause in females.

• AMH also regulates the cyclical action of follicle stimulating hormone (FSH) and luteinizing hormone (LH).

Fate of AMH in Boys and Girls

• Early in the development of a boy, AMH is produced by the testes which inhibit the development of female reproductive organs and thereby promote the development of male reproductive organs. In boys the level of AMH remains high until puberty after which it begins to decrease. 

• Whereas in girls low levels of AMH is produced initially which allows the development of female reproductive structures. The level of AMH is low until puberty but as the ovaries begin to produce eggs and follicles, the developing follicles produce more AMH and the levels increase. over the lifetime, as the reproductive phase begins to halt, there is a decline in the AMH level after which it becomes undetectable.