In anovulation ovaries are not able to release ova more than three months in a row. Anovulation is responsible for infertility in about 20-25% of infertile woman.

Anovulation is usually associated with specific symptoms. However, it is important to note that they are not necessarily all displayed simultaneously. 

  • Amenorrhea (absence of menstruation) occurs in about 20% of women with ovulatory dysfunction. 
  • Infrequent and light menstruation occurs in about 40% of women with ovulatory dysfunction. 
  • Irregular menstruation, where five or more menstrual cycles a year are five or more days shorter or longer than the length of the average cycle.
  • Absence of mastodynia (breast pain or tenderness) occurs in about 20% of women with ovulatory problems.

Anovulation may result from ovarian tissue itself, when ovarian functions are altered, or from disturbed interaction between the hypothalamus, pituitary gland and ovary. It all can be caused by stress or distress.

About half the women with hormonal imbalances do not produce enough follicles to ensure the development of an ovule, possibly due to poor hormonal secretions from the pituitary gland or the hypothalamus.

The ovaries can stop working in about 5% of cases. This may be because the ovaries do not contain eggs. However, a complete blockage of the ovaries is rarely a cause of infertility. Blocked ovaries can start functioning again without a clear medical explanation. In some cases, the egg may have matured properly, but the follicle may have failed to burst (or the follicle may have burst without releasing the egg).

Anovulation is associated with several condition such as endometrial hyperplasia, hyperprolactinemia, anorexia nervosa and thyroid disorders.

Endometrial hyperplasia

Glandular cystic hyperplasia of the endometrium occurs during anovulatory cycles which tend to be longer than the normal menstrual cycle after prolonged persistence of follicles. The extended phase of anovulatory cycles results from prolonged high concentration of estrogen, resulting in endometrial hyperplasia which is processed as glandular or glandular cystic endometrial hyperplasia. 

Hyperprolactinemia

Hyperprolactinaemia or hyperprolactinemia is the presence of abnormally high levels of prolactin in the blood. In women, a high blood level of prolactin often causes hypoestrogenism with anovulatory infertility and a decrease in menstruation.

Anorexia nervosa

In anorexia nervosa (AN), amenorrhea is related to severe calorie restriction and subsequent suppression of the hypothalamic-pituitary axis (a complex set of direct influences and feedback interactions among endocrine glands: the hypothalamus and the pituitary gland). There are regulation changes in gonadotropin-releasing hormone (GnRH) pulsatile release, and reversal of luteinizing hormone (LH) pulsatile secretion to pre-pubertal patterns, with suppression of the pituitary production of LH and follicle-stimulating hormone (FSH). Without normal cycling of LH and FSH, the circulating level of estrogen is very low and ovulation will not occur. 

Thyroid disorders

The ovaries regularly communicate with the other endocrine organs. Thyroid hormones change the sensitivity of the gonads to follicle stimulating hormone (FSH), luteinizing hormone (LH) and prolactin. Besides menstrual cycle disorders, hypothyroidism can also cause an increase particularly in the release of thyrotropin releasing hormone (TRH), which in turn increases the release prolactin, eventually causing hyperprolactinemia, which is an important factor inhibiting the development of pregnancy.

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