Clinical Application of Serum Anti-Müllerian Hormone (AMH) Measurements

[Background] Anti-Müllerian hormone (AMH), which level can be assessed in serum, is a product of follicular granulosa cells of preantral and small antral follicles in the ovary. AMH expression increases prior to follicle-stimulating hormone (FSH)-dependent selection (follicles up to 8 mm) and rapidly decreases thereafter (follicles > 8 mm. Thus, serum AMH level is a reliable marker of functional ovarian reserve as it reflects the pool of growing follicles. Since AMH is relatively cycle independent and has no inter-rater variability, it is considered to be a more reliable biomarker of ovarian function across an array of clinical conditions when compared with follicle-stimulating hormone (FSH) and antral follicular count (AFC).

<Association between AMH and polycystic ovarian syndrome (PCOS)> PCOS is a common endocrine disorder that causes menstrual irregularity and hyperandrogenism in women. It affects approximately 4-20% of women of reproductive age. Women with PCOS have been shown to have elevated AMH levels when compared with women without PCOS as there is an increased number of ovarian follicles in PCOS. Therefore, AMH is being increasingly recognised as a marker for the diagnosis of PCOS. However, a specific cutoff value is yet to be determined. When the issue is addressed, serum AMH levels could potentially replace ultrasound in the diagnosis of PCOS as ultrasound is more costly and less accessible.

<Association between AMH and premature ovarian insufficiency (POI)> POI is defined as the cessation of ovarian function before the age of 40 years. Timely diagnosis is important in order to appropriately counsel and treat the patients with POI.

Prompt initiation of hormone replacement therapy is vital to minimise the risk of long-term health complications including osteoporosis and premature cardiovascular disease. AMH levels were significantly low to undetectable in women with POI. Since AMH is independent of the timing in a menstrual cycle, the measurement may be beneficial in the phase of menstrual irregularity and could potentially help to assess the progression of ovarian senescence.

<Associations between AMH and Fertility> Serum AMH level is an important indicator of women's ovarian reserve and a crucial tool in assisted reproductive technology (ART) for the evaluation of women's fertility. A recent systematic review concluded that basal serum AMH is a strong pretreatment predictor of poor response to controlled ovarian stimulation (COS) and correlates with the risk of ovarian hyperstimulation syndrome. As such, clinicians can individualise the stimulation protocols to optimise the ovarian response. In addition, AMH-based prognostication counselling can be provided to patients with realistic expectation regarding the ART outcomes.