Anti-Mullerian Hormone (AMH) or "Egg Timer" Test
What is Meant by Ovarian Reserve?
Broadly speaking, a woman's ovarian reserve is the amount of good quality eggs remaining in her ovaries. Although men continually produce new sperm, women are born with their lifetime supply of eggs. In other words, women do not produce new eggs and as they age their supply of eggs in their ovaries decreases. As the rate of loss of eggs varies between women, it can be difficult to predict the amount of eggs and level of fertility a woman has as she ages. Therefore, measuring ovarian reserve can be an important part of fertility evaluation and potential advantages of having your ovarian reserve measured include;
- If you have decided to delay starting a family you may wish to check your ovarian reserve to confirm that your supply of eggs is not already significantly reduced.
- A low ovarian reserve is one factor in identifying women who may have a low chance of success from fertility treatment.
- If a woman has an unusually high ovarian reserve she may have polycystic ovarian syndrome (PCOS).
- Measurement of ovarian reserve is helpful in deciding the best dose of medicine(s) to use during fertility treatments such as in-vitro fertilization (IVF).
A number of different blood hormone levels and ultrasound measurements have previously been used to assess ovarian reserve. These include;
- Follicle Stimulating Hormone (FSH) measured on day 3 of the cycle
- Inhibin B
- Antral follicle count
- Ovarian volume assessment
- Clomiphene challenge test
However, there are potential drawbacks and inaccuracies associated with each of those tests.
What is AMH?
Anti-Mullerian Hormone (AMH) is a hormone produced by cells in small developing egg sacs (follicles) that contain an egg in a woman's ovaries. Therefore, AMH gives an indication of the number of eggs being produced during a woman's monthly cycle. The level of AMH in a woman's blood is a good indicator of her ovarian reserve and is helpful in assessing her fertility status. A low level of AMH suggests that there is a significant reduction in the remaining supply of eggs.
Several factors lead fertility specialists to believe that AMH is a good way of measuring ovarian reserve. Some studies in women being treated by IVF have found lower AMH levels in those who responded poorly to fertility drugs. Other tests of ovarian reserve such as FSH must be measured at particular time(s) in the menstrual cycle. One potential advantage of using an AMH test to assess ovarian reserve is that it does not seem to change over the course of the menstrual cycle, and so AMH can be tested by obtaining a blood sample at any time of the month.
How can AMH Results be Helpful?
For women undergoing IVF treatment, AMH results can be used to help choose the best dose of fertility medicine(s) used to stimulate the ovaries. AMH levels may help to identify women who are more likely to over-respond or hyper-stimulate during IVF treatment, and the dose of fertility medicine can be adjusted to minimize that risk. AMH may help to identify woman who have polycystic ovarian syndrome (PCOS). AMH can also help to identify women who have a lower pregnancy rate from fertility treatment.
What are the Limitations of the AMH Test?
In order to give a complete fertility assessment, AMH results need to be interpreted by a fertility specialist taking into account a number of other factors. The implications of a low AMH level may vary depending upon a woman's age. In younger women a low AMH may indicate that it may be more difficult to obtain eggs during fertility treatment, but does not necessarily mean that eggs obtained from treatment will be poor quality. In other words whilst a low AMH indicates a reduced ovarian reserve, it does not necessarily provide information about eggs quality.
What Does the AMH Test Cost?
No Medicare rebate applies for this test and that currently the private fee is $60. This does not include the consultation fee with the fertility specialist.
AMH testing can be undertaken at any time of the menstrual cycle. Oral contraceptives are not thought affect the levels of AMH. However, women taking the oral contraceptive pill whose test results suggest a poor ovarian reserve may wish to have the test repeated after a month of being off the contraceptive pill. If the test is being repeated in this way, women who do not wish to become pregnant need to use other method(s) of contraception, and the pill can be recommenced immediately after the test has been done.
You can download our fact sheet on AMH by clicking on the link below.