Having an ovarian reserve marker is essential to know the possibilities we have when starting an ovarian stimulation cycle. We know that the male is born with the possibility of generating new spermatozoa, as the testicle does not have them. Germ cells in the male are generated again every 2/3 months depending on certain factors.
However, the female is diametrically opposed to this. The germ cells are the egg cells that are present from birth. They are a finite number. It is not possible to generate them. From menarche onwards, within that number of primordial follicles, a few stand out and are visible sonographically, so we move from primordial follicles to follicular recruitment.
The younger the ovary, the greater the follicular recruitment. From the recruitment phase we move on to the follicular selection phase depending on the growth of each one of them, a phase that will end with the development of one of them, which is ultimately the follicle that will provide the egg.
The recruitment and subsequent selection phase generates oestradiol, a hormone that will have a negative impact on the hormone that governs the ovary - FSH - which increases at the beginning of the cycle and decreases as the follicles grow. Its value does not provide information on ovarian reserve. Moreover, it is not a constant marker, it depends on the time of the cycle when it is measured.
This being the case, we have to look for another marker. This other marker could well be the antral follicle count (AFR) ultrasound. Fewer follicles would indicate more depletion and therefore less ovarian reserve. However, this would not be correct either because there is no adequate and stable number of recruitment, it is variable from one patient to another and, in addition, there are situations such as metabolic disorders and PCOS (Polycystic Ovary Syndrome) that do not carry out an adequate follicular selection and follicles accumulate from one cycle to the next.
Fortunately, we have a marker which is the Anti-Müllerian Hormone (AMH) which gives a constant value independent of the time of the cycle. The hormone that provides information about ovarian reserve is AMH, although we normally do a joint study with ultrasound of antral follicle count and AMH values.
