Generality
The anovulatory cycle (or anovulation ) is a dysfunction of the menstrual cycle, characterized by the absence of ovulation.
Anovulation can be suspected in the case of irregular menstrual cycles (both in terms of quantity and duration) or not associated with the typical symptoms of the ovulatory phase (such as breast tenderness, abdominal bloating or mutations in mood).
Anovulation occurs more frequently during adolescence and climacteric. In addition to the premenopausal state, one of the most common causes of ovulation absence is polycystic ovary syndrome. However, the problem can also be determined by hyperprolactinaemia, hypothyroidism and other diseases that cause anovulatory amenorrhea (including functional alterations of the hypothalamic-pituitary-ovarian axis, early ovarian failure and ovarian tumors).
Diagnosis of anovulatory cycles is confirmed by measuring hormone levels in the blood and performing a pelvic ultrasound.
The treatment of anovulation is aimed at the triggering causes. In the absence of pathologies, anovulatory cycles can represent transient conditions.
What's this
The anovulatory cycle consists of the absence of ovulation (ie the failure to release fertilizable eggs from the ovary) and the lack of formation of the corpus luteum during one or more menstrual cycles.
Anovulation may be transient or chronic, remembering that:
- A menstrual cycle can be defined as anovulatory only when it has ended;
- Having two or three anovulatory cycles during the year is normal;
- An anovulatory cycle is a completely physiological phenomenon during childhood, pregnancy, breastfeeding and menopause.
If ovulation is irregular, but not completely absent, it is called oligovulation . This situation is characterized by the lengthening of the rhythm of the menstrual cycle.
What is the menstrual cycle
The menstrual cycle is a delicate chain of physiological events, whose purpose consists in the maturation of the egg cell (female gamete) and in the preparation of an "environment" suitable for its eventual plant. These processes predispose, therefore, to the beginning of a possible pregnancy, in the case in which the fertilization of the oocyte by a sperm of male origin occurs.
The menstrual cycle occurs at regular intervals, on average every 28 days, that is from the 1st day of a period to the day before the start of the next flow. However, some individual variability should be considered normal.
Anovulation is one of the causes of female infertility, since it implies the absence of usable oocytes.
Causes
There are many factors that can predispose to the anovulatory cycle.
Anovulation is a common situation following the appearance of the first menstrual cycles (puberty) and with the approach of menopause, when the remaining oocytes are no longer many.
The anovulatory cycles may depend on conditions affecting the ovaries and the female reproductive system secondary to:
- Polycystic ovary syndrome;
- Perimenopause;
- Early ovarian failure;
- Ovarian tumors.
The phases of the menstrual cycle are associated with the periodic and regular secretion of the ovarian hormones, hypothalamic and pituitary, directly related to fertility. Consequently, different structures of the body (central nervous system, hypothalamus, pituitary and ovary) contribute to maintaining the regularity of menstruation, ovulation and other related events.
For this reason, anovulatory cycles can recognize other varied causes, including:
- Disorders affecting the thyroid, both in the sense of a poor functioning and, on the contrary, of an excessive activity (hypothyroidism or hyperthyroidism);
- Hyperprolactinemia (excessively high values of the hormone prolactin);
- Pituitary alterations (hypopituitarism, aberrant production of FSH and / or LH gonadotropins, adenomas, etc.);
- Hypothalamic disorders (eg inadequate production of GnRH - gonadotropin-releasing hormone - excessive physical activity and rigid diets);
- Cushing syndrome;
- Neoplastic processes;
- Infections;
- High levels of stress;
- Excessive and sudden weight loss;
- Obesity.
An anovulatory cycle can result from systemic diseases, breastfeeding or massive intake of drugs that can weaken the body, causing delays in the onset of menstruation. The absence of ovulation may also depend on hormonal imbalances, post-surgical consequences and genetic factors.
Symptoms and complications
Anovulatory cycles tend to be irregular with regard to duration : in some cases they are close to each other (the time interval between menstruation and the other is shorter than 21 days), other times they are more spaced than normal (beyond 36 days).
Even the considerable variations that can be found in the frequency of the menstrual cycle from month to month can signal an ovulatory dysfunction. Rarely, menstruation is regular without the oocyte being released.
The absence of ovulation may also be associated with the cessation of menstrual periods (secondary amenorrhea) or excessive blood loss (dysfunctional uterine bleeding).
The anovulatory cycle is not in itself associated with other particular physical manifestations. However, in women who do not have ovulation, certain symptoms of the ovulatory phase may be absent, such as:
- Breast tension;
- Abdominal swelling;
- Changes in mood.
In the case of anovulatory cycle, the appearance of cervical mucus is also not tendentially regular (ie it does not appear stringy, more dense and elastic during ovulation).
The main consequence of this dysfunction is female infertility . It should be remembered, in fact, that even when ovulation occurs normally and a woman wishes to undertake a pregnancy, the chances of conception are around 25% each month. If the cycle is anovulatory or irregular, the possibility of conceiving is inferior or null, since a female gamete for fertilization is not available. In general, the difficulty in getting pregnant is the main symptom that leads to undergoing medical tests.
Other factors associated with ovulation may be compromised, making procreation difficult, such as:
- Poor quality of cervical mucus;
- Excessive or defective thickening of the endometrium (tissue that covers the inner wall of the uterus, at which level the mature egg cell is implanted if it is fertilized);
- Abnormally low progesterone levels;
- Short luteal phase.
Anovulatory cycle: how to recognize it
The monthly accuracy in the onset of menstruation does not guarantee that ovulation has occurred.
In a menstrual cycle, the variable that determines its duration is ovulation, since from that moment the luteal phase begins (a period that goes from the release of the oocyte to the beginning of menstruation). The latter is, in fact, more constant and requires 12 to 16 days (average duration: 14 days).
In anovulatory cycles, the lack of ovulation does not mean, then, that there was no ovarian activity.
To know if ovulation has occurred, it is possible to use a basal temperature measurement that tends to increase normally around the 14th day of the menstrual cycle; if the trend is, however, a continuation of ups and downs it is likely that anovulation has occurred.
Diagnosis
To evaluate the causes responsible for anovulation, it is necessary to record precisely on the menstrual calendar the beginning of each cycle (ie the day on which the flow appears). The doctor may also require the detection of the basal temperature, in addition to proceeding with some blood tests .
In particular, the diagnosis of anovulation is confirmed by measuring the levels of hormones involved in the menstrual cycle. Among these, progesterone is quite significant, especially when measured on the 21st day of the cycle: after ovulation, the values for this hormone increase.
Performing an ultrasound and a pelvic exam will check the conditions of the uterus and ovaries and the possible presence of cysts in the ovaries (polycystic ovary), as well as allowing the detection of a possible follicle (or corpus luteum).
Classification of anovulatory states
To assign women to their respective groups, the classification of the World Health Organization (WHO) is based on three parameters:
- Prolactin level;
- Level of gonadotropins LH and FSH;
- Estrogen level.
| Group | Diagnosis | Features |
| THE | Pituitary hypothalamic failure |
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| II | Pituitary hypothalamic dysfunction |
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| III | Ovarian failure |
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| IV | Congenital or acquired disorder of the reproductive tract |
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| V | Infertility with hyperprolactinemia and lesions in the pituitary hypothalamic region |
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| YOU | Infertility with hyperprolactinemia and absence of detectable lesions in the pituitary hypothalamic region |
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| VII | Amenorrhea in the absence of elevated prolactin values and signs of lesions in the pituitary hypothalamic region |
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Therapy
The treatments of the anovulatory cycle depend on the triggering cause. In any case, it is always recommended to contact a specialized doctor.
Sometimes, it is possible to manage the condition simply by adopting an adequate diet, the practice of moderate exercise, stress control and other lifestyle changes .
In severe cases, doctors can prescribe drug treatments with clomiphene citrate, especially for women who suffer from polycystic ovary syndrome. Regular ovulation can also be induced by resorting to hormone replacement therapy, based on the administration of estrogen-progestins. Metformin, a medicine used for diabetes, is also useful in many cases, alone or in combination with other substances.
Other treatments of the anovulatory cycle may include gonadotropin-releasing hormone agonists and anti-androgens . On some occasions, anovulatory cycles are treated with surgery .
