Anti-Mullerian Hormone testing, also known as an AMH test, is a blood test commonly used to check a woman’s ovarian reserve as part of fertility tests and assessment. It predicts how many eggs a woman has left in her ovaries. However, it cannot diagnose the quality of a woman’s eggs.
About one in six Australian couples experience problems with fertility, and the most important factor influencing the chance of conceiving, whether naturally or through fertility treatments such as IVF, is the female partner’s age. This is because women are born with their lifetime supply of about one million eggs. The number of eggs available to mature and go through the reproductive cycle declines as a woman gets older.
Egg numbers in a woman’s ovaries naturally reduce over her life. In a woman’s monthly menstrual cycle, several eggs will begin to mature but generally only one egg reaches maturity and is released at ovulation. The other partly matured eggs are no longer available in future cycles. As a woman ages, so too does the quality of her eggs, particularly for women 37 years of age and over.
It is estimated that about 10 percent of women will experience an accelerated loss of eggs (or “diminished ovarian reserve”) by the time they reach their mid-thirties.
At the age of 36, a woman’s chance of conceiving naturally is halved, compared with her chance at 20 years of age. By the time a woman turns 41, that chance is just 4%, and, even after fertilisation, many embryos are not viable for a successful pregnancy.
If there is a family history of early menopause, severe endometriosis, or previous ovarian surgery or chemotherapy, there is an increased risk of an early reduction in ovarian reserve.
The AMH test method is a blood test that measures Anti-Mullerian Hormone, which is a hormone secreted by cells in developing egg sacs or follicles in the ovaries. Also referred to as the “Egg Timer” test, AMH blood tests are usually conducted in combination with an ultrasound of the ovaries to provide the best indication of ovarian reserve.
A woman’s level of AMH changes very little during the menstrual cycle, so this blood test can be taken at any time and sent to a specialist pathology lab for assessment.
AMH tests provide a good estimate of the number of eggs a woman has in her ovaries. Typically, a Fertility Specialist would then compare this with the “normal” range for your age to identify potential issues.
In general, women with higher AMH levels will respond better to IVF treatment – this is because more eggs can be retrieved and this can provide a higher IVF success rate.
However, unusually high levels of AMH could result in an over-stimulated response to IVF medication. High levels of AMH associated with many small follicles may also indicate Polycystic Ovarian Syndrome (PCOS), which can also cause problems with fertility. Other rare conditions may result in very high AMH levels too.
If your ovarian reserve is diminished, it will be harder to fall pregnant naturally and you may also have an increased risk of miscarriage. Depending on your AMH test fertility result, you may wish to try for a baby sooner or look into fertility treatments such as IVF. It’s important to remember that there is no treatment to improve the quality of your eggs.
Ask your GP for a referral for an AMH blood test, to be performed by a specialist fertility laboratory.