We speak of anovulation in the face of the inability, temporary or permanent, of the ovary to emit an oocyte during the cycle. However, without an oocyte, no fertilization can take place, so it is impossible to get pregnant. Depending on the cause of the anovulation, however, there are different treatments to overcome this infertility.

As a reminder, ovulation refers to the moment in the cycle when one of the ovaries expels an oocyte. The ovarian follicle matured at the end of the follicular phase (first phase of the ovarian cycle) ruptures and releases an oocyte in the tube. This oocyte then migrates to the upper part of the tube, where it will remain fertilizable by a sperm for 24 hours.

We speak of anovulation when there is no ovulation: the ovaries do not produce any fertilizable oocytes. This disorder can be temporary or permanent. Anovulation is one of the ovulation disorders.

Anovulation is manifested by irregular periods, or even amenorrhea (absence of menstruation). This amenorrhea may be primary or appear at the stop of contraception. Under the pill, menstruation was regular because it was due to hormonal deprivation, and therefore artificial.

In the event of anovulation, if the woman makes a temperature curve to detect her ovulation, the curve will be flat. If she uses ovulation tests, these will remain negative. If after 3 months, no ovulation is detected by either of these methods, it is advisable to consult.

During the infertility assessment, various examinations will be carried out in order to confirm anovulation and find its origin: hormonal assessments (LH, FSH, AMH, estradiol, progesterone), ultrasound, etc.

Different pathologies can lead to anovulation.

These disorders can be of central or “high” origin, ie affecting the hormonal control centers (pituitary, hypothalamus) of FSH (follicle stimulating hormone) and LH (luteinizing hormone), both. key hormones of the ovarian cycle.

Unstimulated, the ovaries do not produce an oocyte. Here are the most common causes:

• a congenital anomaly or a chromosomal anomaly, as in Kallmann-De-Morsier syndrome, which causes a deficiency in GnRH (hormone which stimulates the pituitary gland and therefore the secretion of LH and FSH);
• a benign tumor in the hypothalamus or pituitary gland, the most common being the prolactin pituitary adenoma, causing an abnormally high secretion of prolactin (hyperprolactinemia) which disrupts the secretion of GnRH;
• anorexia nervosa and / or extreme thinness may also affect the functioning of the hypothalamic-pituitary axis, by reducing the production of GnRH. Ovulation may then become irregular or stop;
• psychological disorders, emotional shock, and significant stress can also cause ovulation to be blocked over several cycles. The same goes for a very intensive sporting practice;
• Sheehan’s syndrome: rare, this is necrosis of the pituitary gland secondary to postpartum hemorrhage or head trauma.

The problem may be ovarian in origin. We then speak of low or peripheral origin. The most common causes are:

• polycystic ovary syndrome (PCOS) or ovarian dystrophy. This endocrine pathology which affects 5 to 10% of the female population is manifested by the abnormal accumulation of small follicles which do not enter into growth. Ovulation is then irregular, of poor quality or completely absent, leading to subfertility or infertility. Thus, 50% of women with PCOS have primary infertility and 25% have secondary infertility (1);
• an ovarian cyst, sometimes due to endometriosis (endometriotic ovarian cyst), which will affect the proper functioning of the ovary;
• early ovarian failure (POI) affects 1% of women under 40. It is defined as amenorrhea lasting more than four months before the age of 40 with a high level of FSH. It may be the consequence of a chromosomal abnormality (Turner syndrome, fragile X syndrome), treatment with radiotherapy and / or chemotherapy, ovarian surgery, an autoimmune disease, more rarely from a viral cause. But in more than 80% of cases, no cause is found for this “early menopause”, as it is often called, wrongly because in some cases, IOP is not final unlike physiological menopause which it is (2).

Finally, certain general diseases can disrupt the functioning of the ovaries or hormonal secretions and cause anovulation: hypothyroidism, kidney failure, severe hepatic failure, diabetes, Cushing syndrome. Similarly, certain drugs (certain neuroleptics, tricyclic antidepressants, selective serotonin reuptake inhibitors, antihypertensives, anti-epileptics, etc.) can be the cause of hyperprolactinemia.

Anovulation leads to infertility because without ovulation, there is no oocyte and therefore no fertilization possible with a sperm. This absence of a female gamete therefore makes any pregnancy impossible. Ovulation disorders, which includes anovulation, are also responsible for 35% of infertility cases of female origin (3).

This infertility may however only be temporary depending on the origins of the anovulation, which may itself be temporary or permanent.

Treatment of anovulation depends on its cause:

• in the case of a prolactin-producing pituitary adenoma, drug therapy is the first-line treatment. Surgery is only considered in the event of failure or a large tumor;
• in the event of PCOS, an ovulation induction treatment will be offered. Clomiphene citrate has until now been the first-line treatment for the management of infertility linked to anovulation of PCOS but in recent years, other treatments, aromatase inhibitors (letrozole in particular) have showed promising results (4);
• in the event of precocious ovarian failure, egg donation is the only therapy currently possible. The chances of success of this technique are good (around 30% per transfer) but due to the lack of donors, the average time between registration and donation is 2 years (5);
• an endometriotic ovarian cyst can, if it causes infertility, be punctured, surgically removed or destroyed with laser or plasma energy, an emerging technique used by some teams in France;
• in the event of a general illness, the treatment of this disease most often allows ovulation to be restored;
• in certain disorders of the hypothalamic-pituitary axis, or even anorexia nervosa, the installation of a GnRH pump by the subcutaneous route is sometimes proposed. By mimicking the functioning of the hypothalamus, this device helps restore ovulation. Treatment with pulsatile GnRH is well tolerated and makes it possible to obtain a satisfactory rate of pregnancies, the evolution of which is favorable: the pregnancy rate per cycle is 25% and the average number of treatment cycles necessary to obtain ” a pregnancy of 2,8 (6).