What is Anti-Mullerian Hormone and why is it important?
By Laurentia Campbell
Anti-Mullerian Hormone, or AMH (also called Müllerian inhibiting substance or MIS), is a peptide (protein) growth factor in the body that instructs other cells to grow and develop. It is a vital member of the large TGFβ family of growth and differentiation factors that is best known for its role in the body for its role in promoting sex cell (such as the female egg and male sperm) production.
It has a pivotal role in both female and male reproduction and fertility. In males, it helps the testes develop and thus plays an essential role in the production of sperm, in females it helps the uterus, womb and follicles develop. As the follicles of the womb are where the egg is made and released from at day 14 of the menstrual cycle, under the signal of follicle-stimulating hormone (FSH) and after a surge in luteinizing hormone (LH), low AMH can be a sign of low egg count. Low AMH is thus associated with infertility and doctors will test AMH biochemical levels when diagnostically testing fertility. It can also be used to determine the chance of success of treatments such as egg freezing and in-vitro-fertilisation (IVF) and in ovarian tumour surgery success determination and relapse risk detection.
What is fertility?
Fertility is a measure of a person’s ability to reproduce and produce fertile offspring. In a female, it is achieved by the release of a fertile egg from the follicles of a woman’s womb. GnRH (Gonadotrophin Releasing Hormone) stimulates the release of Follicle Stimulating Hormone (FSH), Testosterone, Progesterone and Oestrogen hormones (which triggers the egg to mature in the womb) and Luteinizing hormone or LH (which triggers the release of the egg at day 14 of her menstrual cycle). AMH is released from the granulosa cells of the womb from birth to menopause and helps the follicle develop. If the egg released from the follicle in the womb meets a fertile male sperm, it will go on to implant in the womb lining, which is maintained by Progesterone, which will develop into the placenta when the egg and sperm fuse to make a zygote. The zygote is a ball of dividing cells which become an embryo which grows into a child. Oestrogen and Progesterone is needed throughout the pregnancy to maintain the pregnancy.
Fertility in a male is achieved by the release of a fertile sperm from the Testes in response to GnRH stimulating the release of Testosterone, Follicle Stimulating Hormone (FSH) and Luteinizing hormone or LH. LH stimulates Testosterone, FSH stimulates sperm production. The sperm is stored in the scrotum until ejaculation in sexual reproduction.
What do AMH levels in women indicate?
AMH levels are used in fertility medicine as an indicator of the number of eggs a woman has, as AMH is believed to reflect the size of her resting follicular pool (the number of eggs in the follicles of her womb). AMH levels do not change in menstruation, but they do change with certain reproductive disorders such as polycystic ovarian syndrome (PCOS) and as you age. Therefore, it is useful to determine a woman’s reproductive lifespan. A low AMH level, for example with PCOS, is often a sign of decreased fertility.
AMH levels are also taken as a biomarker for ovarian tumours. It is used post-operatively (post ovarian tumour removal) as a test of the success of the surgery and the chance of relapse and disease recurrence. As AMH also plays a role in helping decide which egg to grow (and thus inhibiting the growth of other eggs in the follicle) it is also being considered as a therapy itself in inhibiting ovarian tumour growth in ovarian cancer.
Should I get my AMH levels tested?
If you are a woman and have any worries or concerns at all about your fertility and reproductive health (or are considering egg freezing, IVF or are just curious about your potential reproductive lifespan), it is very worthwhile getting your AMH levels tested. The test is very quick and relatively easy and can be a simple way of determining your reproductive capacity. This test is not currently offered on the NHS but can be accessed privately both in the UK and abroad for a meagre fee. There are many reproductive medicine clinics and fertility institutions which will offer the test, and some allow you to do the test at home with results within 1–2 working days. Often though, for a full clinical picture, it is best to do the test with a scan of your womb also, a transuterine ultrasound scan, to determine more exact details of your reproductive health. This way you can have the most clarity about your actual position when considering fertility options or planning your future family. The test will not protect you from infertility but will give you more of a clear outlook as to your reproductive position.
Copyright Laura Campbell 06/11/2022
