Order Guide: AMH
An individual’s fertility is associated with several genetic and non-genetic factors (i.e. obesity, smoking status, thyroid disease). Canadian guidelines typically recommend infertility investigations in couples after 12 months of unprotected intercourse in women under 35 years of age, and after 6 months in women between the age of 35-and 40. We typically refer all women above the age of 40 immediately to an infertility specialist. Women who have other medical conditions including but not limited to endometriosis, PCOS, and a history of pelvic inflammatory disease can be referred at any time.
A woman’s ‘ovarian reserve’ represents the reproductive potential or quality of eggs that are present in a woman’s ovaries. Anti-Mullerian Hormone (AMH) is a hormone that has been found to be a useful marker for ovarian reserve.
All women are born with something called ‘primordial follicles’. These represent the total number of ‘eggs’ that have the potential to be fertilized over the course of a woman’s lifetime. A small number of primordial follicles become ‘antral follicles’ during ovulation, and each one contains an immature egg. Over the course of a woman’s lifetime, the total number of primordial follicles decreases, and the total number of antral follicles reduces with each cycle thus associated with a reduction in fertility. Doctors can see the total number of antral follicles at any point in a woman’s menstrual cycle, though it is often preferred to evaluate the total number of antral follicles in the 1st half of a woman’s menstrual cycle.
AMH is a simple, non-invasive blood test that is a measure of ovarian function and has a direct correlation with how many eggs can be received during IVF stimulation. It can be measured at any point in a woman’s cycle and is considered the best biomarker for measuring fertility. Because there is little variability in a woman’s menstrual cycle, you don’t need to complete it on a specific day before or after your period. A low AMH level can help physicians estimate a woman’s total egg count. AMH gradually declines over a woman’s lifetime and becomes undetectable at menopause.
AMH levels do not correlate with the time to achieve pregnancy. AMH is a relatively new hormone measurement, and at present time there isn’t enough evidence to use it for the prediction of pregnancy loss, or for estimating a general fertility status outside of IVF assessments.
AMH levels are higher in women with PCOS. It is currently being investigated for use as a marker in the diagnosis of PCOS, but currently, guidelines do not recommend the use of AMH for diagnosing PCOS.
If you are trying to get pregnant and have a low AMH, we recommend following up with an OBGYN to have a further conversation about your fertility and future fertility planning.
A normal AMH reflects your ovarian reserve today (the total number of eggs that can be retrieved during an IVF cycle). A normal number doesn’t mean it will be easy to get pregnant, as there are a number of factors involved in pregnancy. Similarly, a low AMH level does not mean you cannot get pregnant if you were to try on your own.
Some of our patients like to track their ovarian reserve over time. We cannot predict based on your prior values how quickly your AMH will decline, so if you are concerned about your fertility we suggest seeking a follow-up with a fertility specialist.