If there was a 'Holy Grail' of female fertility blood tests then I think AMH (Anti-Mullerian Hormone) is the one. It is perhaps the single most important female fertility blood test to have carried out if you have been trying to conceive without success.
What is AMH?
At birth, every woman is born with the total amount of eggs she is ever going to have. All of these eggs are stored inside the ovaries in tiny sacs called antral follicles. Most of these antral follicles are too small even to be seen by ultrasound. Each month a certain number of antral follicles start to mature and one or two reach full maturity and release an egg at ovulation.
AMH is a substance produced by cells inside these antral follicles and can therefore be used as a marker to determine how many antral follicles are left in the ovaries.
Over the course of a womans lifetime the number of antral follicles decreases as they gradually get used up during every menstrual cycle. A decrease in antral follicles means a decrease in AMH levels.
AMH levels naturally decrease over the course of a womans lifetime as seen in the graph below.
What is low AMH?
A low AMH level means you will find it more difficult to get pregnant either naturally or with fertility treatment such as IVF. This is because there are a low number of eggs remaining in your ovaries. (Also known as a low Ovarian Reserve).
Fertility clinics use AMH levels to determine what type of treatment is most suitable. If AMH levels are found to be low then IVF is advised. At least one fertility clinic that I'm aware of in Ireland offers multiple cycles for women with extremely low levels. This means they will carry out 2 to 3 egg collections, freeze the eggs and then inseminate all the eggs when they have a good number. This gives an increased chance of success.
What is high AMH?
AMH can be used to diagnose PCOS (Polycystic Ovarian Syndrome). In some cases there are no other symptoms of PCOS only an elevated AMH level. Some women struggle to conceive with undiagnosed PCOS simply because they have never had their AMH level checked.
Women with PCOS have an increased number of antral follicles and therefore produce a high level of AMH. This high level of AMH can often prevent the follicles from reaching full maturity, thereby preventing ovulation.
How can I get my levels checked?
AMH levels are measured by a blood test. Since levels do not fluctuate during the menstrual cycle this blood test can be taken on any day of your cycle.
The blood test is generally not available publicly in Ireland but all fertility clinics provide the test. Your GP may be able to arrange the test for you.