Ovulation disorders are the most frequent cause of female infertility!
Egg formation begins in the womb during the intrauterine development period at the end of the first trimester and continues until 28-30 weeks of pregnancy. During this time both ovaries contain a total of about 7 million premature eggs, most of which stop growing at the first meiotic stage. Following atresia, which reduces the number of eggs and at the time of birth, there are only 2 million eggs. Around the time of menarche (onset of menstruation), both ovaries contain less than 500,000 eggs. A small part of these eggs gradually matures during the reproductive period (from menarche to menopause) but most go through atresia or spontaneously disappear.
Ovulatory dysfunction is characterized by changes in menstrual cycle regularity and duration. A normal menstrual cycle lasts 25 to 35 days, an average of 28 days.
Anovulation may be associated with primary and secondary amenorrhea, oligomenorrhoea.
Primary amenorrhea is when menstruation has not begun before the age of 16. Also, chronic stress, starvation or malnutrition can cause primary amenorrhea. Primary amenorrhea is also observed in cases of congenital developmental disorders of the uterus, vagina or hymen.
Primary amenorrhea is divided into two groups:
Hypergonadotropic hypogonadism is often linked to gonadal development disabilities. In the case of Turner syndrome, one X chromosome is missing (karyotype 45, X). These patients have so-called sexual infantilism – a small uterus and atrophic ovaries, but the fallopian tubes and vagina are normal. Patients have high FSH, LH and low oestrogen levels.
Primary amenorrhea is observed in patients with hypothalamic lesions (hypogonadotropic hypogonadism). It is caused by inadequate synthesis of GnRH and neurotransmitters, as well as isolated gonadotropin deficiency.
Secondary amenorrhea is when in a case of a regular menstrual cycle the menstruation is absent for more than 6 months.
First, it is necessary to exclude pregnancy (test HCG).
Secondary amenorrhea is associated with ovarian dysfunction which may be caused by thyroid, adrenal or pituitary disorders. One of the most common causes of secondary amenorrhea is premature ovarian exhaustion syndrome, which is caused by the depletion of ovarian reserve before 40 years of age.
Oligomenorrhoea (infrequent periods, cycle length > 35 days, 4-6 periods per year) is a hypothalamic-pituitary-ovarian axis dysfunction, which is the most common cause of ovulatory dysfunction related to infertility.
Oligomenorrhoea can be caused by:
- Prolactinoma (pituitary microadenoma, macroadenoma);
- PCOS; in this case can also hyperandrogenism can be observed – acne, hirsutism, increased hair loss;
- Thyroid disorders – thyrotoxicosis, hypothyroidism, Graves’ disease;
- Perimenopausal hormonal fluctuations;
- Intense, prolonged physical activity, sports;
- Eating disorders – Anorexia nervosa, Bulimia nervosa;
- Overweight, obesity, BMI > 29.