The Anti-Mullerian Hormone (or AMH) is a hormone produced by the primary follicles (small clusters of cells that surround immature eggs) in a woman’s ovaries. An AMH test can give you an indication of your ovarian reserve compared to other women of a similar age. Unlike men who continually produce sperm, women are born with their lifetime supply of eggs. It can be important to know what your ovarian reserve is when considering having a baby.
What is the AMH test?
An AMH test is the best biochemical marker of a woman’s ovarian reserve. The test itself is a hormonal blood test that estimates the number of eggs at rest in a woman’s ovaries. As a fertility specialist it gives me a very good idea of what the ovary is capable of in the context of fertility treatments. This can determine how strong a candidate a woman is to undergo certain fertility treatments (like IVF and egg freezing) and how successful those treatments are likely to be. However, it is also important to remember that an AMH level does NOT predict your chances of a natural conception in the near future.
Who should have an AMH test?
An AMH test may be requested for women contemplating their fertility options and wanting to investigate their ovarian reserve. Women planning IVF or fertility treatment will usually have an AMH assessment, alongside other markers of ovarian reserve such as an ultrasound antral follicle assessment. The AMH test is the most modern way to understand a woman’s ovarian reserve. It also creates the opportunity to personalise a strategy to achieve the best possible individualised treatment outcomes.
What factors contribute to a low AMH?
Age affects every woman’s AMH level. From birth, women have already produced all the eggs that they will release in their lifetime. This starting number is genetically determined and can vary greatly between women. However, whatever a woman’s starting point, her ovarian reserve will dramatically reduce over time. Eggs are steadily lost until the age of 30 years. After this time, the rate of loss increases rapidly, especially after 35 years and this can be one factor that contributes to a lower chance of live birth in older women. There are some circumstances where a low AMH level is inaccurate, such as when AMH is measured in women using the pill or who have hypothalamic dysfunction.
How are the results of the AMH test measured?
An AMH test is not a measure of egg quality – and our best estimation of quality and potential of eggs to become a baby is a woman’s age. AMH is a measure of quantity – and can infer how many eggs can be expected to develop in a fertility treatment cycle. It is important to interpret the AMH result in context of other factors that influence fertility.
What is a healthy range for an AMH test?
AMH levels can vary widely, even amongst fertile women. Interpretation of the AMH level should be considered in the context of a woman’s holistic situation and her plans for future fertility. A low AMH should not necessarily be considered as a stand-alone concern, and is not associated with a reduced monthly chance of getting pregnant.
However, if a woman has complex or multifactorial infertility, a low AMH can reduce her chance of having a baby. A low AMH can also influence whether or not a woman is a strong candidate for preventative strategies like elective egg freezing. The table below depicts the normal range for AMH at different ages.
What can a woman do if she has a low AMH?
There is no known therapy that can increase the number of eggs in the ovary. What we can do is take proactive action. If I see a patient and she has a low AMH and has presented a history of infertility, I would be more inclined to consider recommending more advanced treatment sooner. I would also discuss proactive family planning strategies if she wishes to have more than one child in the future, such as frozen embryo banking.
How can I determine the quality of my eggs?
Age is the best indicator of egg quality. Other lifestyle factors such as being overweight, smoking and exposure to environmental toxins might affect a woman’s egg quality. Over time, eggs can become metabolically fatigued which makes them more prone to genetic changes. In older eggs, chromosomal abnormalities can occur before fertilisation and during early cell divisions reducing the chances of forming a healthy embryo and therefore a healthy baby.
How do I get an AMH test?
Any woman who wants to know more about her fertility should see a general practitioner and request a referral to see a fertility specialist. Your GP can order an AMH test (and other tests relevant to fertility like routine antenatal screening investigations) so that your result is available to discuss at your fertility consultation. This might include checking things like infection status, rubella and chickenpox immunity and your blood group.
The most important message about AMH is that it is not a standalone measure of a woman’s current or future fertility. The result should be interpreted in the context of an individual and her plans for future fertility, as a part of a comprehensive assessment with a fertility specialist.
If you are planning for pregnancy or already trying and would like to have an AMH test please contact your local fertility specialists: