AMH (Antimullerian Hormone) is a key hormone. It is secreted by the follicles which house the eggs in our ovaries. It’s thought that AMH levels correlate with the number of viable eggs remaining in a woman’s ovary. In women who suffer from a condition known as diminished ovarian reserve (DOR), this number can often be quite low, indicating that there are few remaining follicles within the ovary. What isn’t widely known, is that the testing of AMH can also be a useful test for women with PCOS, particularly in those who are struggling with receiving a diagnosis.
AMH is secreted mostly by the small antral follicles in the ovary that are between 5-8mm in size. In many women with PCOS, there is an increase in the number of this type of follicle – in essence, the follicles begin to develop and then stall before they are ovulated. Recent research also suggests that in addition to the increased number of antral follicles in the ovary of women with PCOS, there is also an increased production of AMH by the individual follicle cells.
Coincidentally, too much AMH may actually be a major culprit in stopping ovulation from happening. In a normal ovary, AMH works to slow and prevent the premature development of the follicles before they are mature – keeping the ovary from eveloping eggs prematurely. AMH works by reducing the ovary’s receptors to FSH, the main pituitary gland hormone that causes an egg to develop each cycle.
AMH Values correlate with antral follicle count (AFC) of the women by transvaginal sonography. The agreement table of AMH values with AFC in given below.
When the AMH is much too high, as it is in PCOS you can imagine that this effect can go too far and the production of a healthy egg every cycle can be halted. It’s not known exactly what causes the ovarian cells in PCOS to overproduce AMH however it’s thought that it may be related to increased levels of the pituitary hormone LH. Normally LH is released in a strong surge that triggers ovulation – but when it is too high for too long it can inhibit ovulation and cause the overproduction of testosterone. AMH levels also directly correlate to blood levels of testosterone, however it’s diffcult to know whether this is cause or effect. It’s thought that perhaps there may even be an slight mutation in the AMH gene or AMH receptors in women with PCOS.
In clinic, women who have gone undiagnosed with PCOS for years – running a simple AMH test and correlating the results with other aspects of the case has brought clarity to the cases of these many women who have struggled with undiagnosed hormonal problems throughout their lives. Fortunately, AMH is a simple blood test that can be done on any cycle day.
In women who don’t necessarily have the other obvious signs of PCOS, or who are lean, this one test can often help to differentiate the condition. It’s important to know that AMH levels decrease with age and as such you should correlate these results with your age. Another important thing to note is that there are two different units commonly used for measuring AMH – so please check carefully as to the unit your measurement was taken in.
#The 3 Criteria to diagnose PCOS are 2 of the 3 following symptoms :
Polycystic Ovaries on Ultrasound (multiple small follicles)
Clinical or Lab Markers - indicating increased androgens like hirsutism, adult acne and hair loss.
AMH is now almost a replacement for the polycystic ovaries on ultrasound – since it reﬂects the ovary’s imbalance of hormones that causes ovulation to stall. In addition, it’s quite rare to see polycystic ovaries on ultrasound in women over 35, and in women who ovulate who have PCOS – yet you can still often pick up elevated AMH levels in this group.
Typical age-related ranges for AMH are listed below. As mentioned previously, women with PCOS will tend to have AMH levels above the average range for their age bracket.