The anti-Müllerian hormone or AMH was discovered in the 1950s by researcher Alfred Jost. Present from the very first weeks of gestation, it plays a key role in the formation of the sexual organs of the unborn child. Indeed, between the 8th and 10th week of pregnancy, Müllerian Inhibiting Substance (MIS) as it is also called, is secreted by Sertoli cells in the gonads (future testes) of male embryos. The objective: to inhibit the development of the Müllerian ducts which form the outline of the uterus, tubes and part of the vagina. At the same time, the gonads secrete testosterone which promotes differentiation to a male genitalia (development of Wolff’s ducts).

Conversely, in female embryos, Müller’s ducts develop into the female genital tract, in the absence of AMH.

 After birth, the anti-Müllerian hormone can be detected:

• In men in whom it is secreted from uterine life until puberty. During adult life, AMH remains expressed in seminal fluid.
• In women in whom it appears, after birth, under the action of the granulosa cells of the follicles. Present in very small quantities, it nevertheless plays an important role in folliculogenesis and is, as such, an indicator of follicular reserve (or ovarian reserve).

The analysis of AMH is a key element of the infertility assessment, in the 2 members of the couple.

Indeed, in women, the level of AMH in the blood tends to decrease with age in parallel with the number of follicles, unlike other pituitary hormones (FSH and Inhibin B). As such, the anti-Müllerian hormone is considered to be the best reflection of the ovarian reserve. In addition, AMH is a good indicator of the success rate of certain medically assisted procreation (AMP) protocols and of the possible risks of ovarian hyperstimulation. Indeed, there is a correlation between the level of AMH (high) and the number of oocytes punctured after ovarian stimulation. Finally, even if its evaluation is not recommended for diagnostic purposes (no threshold value established), the level of anti-Müllerian hormone can be, when it is high, an indicator of polycystic ovary syndrome (PCOS). ). This increase is explained in particular by the increased number of small growing follicles in patients with this syndrome.

In men, the level of AMH is a good indicator of spermatogenesis. Indeed, according to some research work, the level of AMH in seminal fluid is considerably lower in men with azoospermia than in patients without fertility problems. Moreover, this same rate correlates with the number of sperm and the size of the testes. The evaluation of the AMH level is therefore not only important in the context of a fertility assessment, but also extremely useful for specifying a treatment protocol in azoospermic patients, since the azoospermia is non-obstructive. Finally, the AMH level is useful in the search for certain pediatric male pathologies (ectopic testes, precocious puberty, etc.).

Recommended as part of the infertility assessment of the two members of the couple, the analysis of serum anti-Müllerian hormone markers should be studied with great caution in several ways:

• In women, it should be observed with regard to the age of the patient and the antral follicle count (CFP) by ultrasound. Thus, if some studies have shown that there was a threshold AMH value below which pregnancies become exceptional for some women (aged 41/42), others have put forward that a rate low AMH is not a factor excluding young couples (under 30) who are candidates for IVF. Another particularity to note: the level of AMH is not an indicator of the quality of ovulation.
• In humans, the AMH analysis should be observed in connection with the spermogram and the patient’s history in particular.

 However, it is generally considered that:

• in women, the normal level of AMH is between 2,45 and 5,95 ng / ml on the 3rd or 4th day of the cycle. An analysis revealing a threshold below 0,75 ng / ml may be a sign of a possible poor response to stimulation treatment and should therefore be discussed with the practitioner. Finally, an AMH level greater than 6 or 7 ng / ml can also suggest difficulties in conceiving (case of patients with PCOS), but must again be studied on a case-by-case basis.
• in humans, the normal level of AMH is between 3,1 to 5,3 ng / ml.