Anti-Müllerian hormone (AMH), a marker of ovarian reserve, declines over a woman's reproductive lifespan. AMH is highly correlated with a woman's age and number of primordial ovarian follicles and has been shown to predict time to menopause in women in their 40s. For these reasons, it was assumed that AMH levels could predict a woman's reproductive potential or serve as a 'fertility test'. Recently, studies have sought to determine the association between AMH and fertility.
AMH is a predictor for ovarian response in vitro fertilization (IVF). Measurement of AMH supports clinical decisions, but alone it is not a suitable predictor of IVF success. Additionally, AMH levels are used to estimate a woman's remaining egg supply.
According to the UK NICE guidelines of in vitro fertilization, an anti-Müllerian hormone level of less than or equal to 5.4 pmol/l (0.8 ng/mL) predicts a low response to ovarian hyperstimulation, while a level greater than or equal to 25.0 pmol/l (3.6 ng/mL) predicts a high response. Other cut-off values found in the literature vary between 0.7 and 20 pmol/l (0.1 and 2.97 ng/ml) for low response to ovarian hyperstimulation. Subsequently, higher AMH levels are associated with a greater chance of live birth after IVF, even after adjusting for age. AMH can thereby be used to rationalize the program of ovulation induction and decisions about the number of embryos to transfer in assisted reproduction techniques to maximize pregnancy success rates whilst minimizing the risk of ovarian hyperstimulation syndrome (OHSS). AMH can predict an excessive response in ovarian hyperstimulation with a sensitivity and specificity of 82% and 76%, respectively.
The level of AMH in the blood can help doctors estimate the number of follicles inside the ovaries, and therefore, the woman's egg count. A typical AMH level for a fertile woman is 1.0–4.0 ng/ml; under 1.0 ng/ml is considered low and indicative of a diminished ovarian reserve.
Measuring AMH alone may be misleading as high levels occur in conditions like polycystic ovarian syndrome and therefore AMH levels should be considered in conjunction with a transvaginal scan of the ovaries to assess antral follicle count and ovarian volume.
Polycystic ovary syndrome (PCOS) is an endocrine disorder most commonly found in women of reproductive age that is characterized by oligo- or anovulation, hyperandrogenism, and polycystic ovaries (PCO). This endocrine disorder increases AMH levels at nearly two to three times higher in women with PCOS than in normal type women.