Ovulation lack causes

A lack of ovulation is known as anovulation. In these cases the egg does not mature and hence ovulation fails to take place. Normally, ovulation refers to the release of an egg from the ovary. This happens to the hormonal levels fluctuating during the menstrual cycle. This must happen in order to achieve pregnancy naturally. 


If ovulation is irregular, but not completely absent, this is called oligo-ovulation. Both anovulation and oligo-ovulation refer to irregularities or aberrations from the normal ovulation process and are both different kinds of ovulatory dysfunction. Ovulatory dysfunction is a common cause of female infertility, occurring in up to 40 percent of infertile women.

There may be various causes behind anovulation. Some medications, conditions, and external factors that affect hormone levels can cause anovulation. Sometimes, a woman may have one anovulatory cycle and then go back to a regular cycle. Other times, it is a chronic problem.

When anovulation occurs, a woman cannot get pregnant. For women who have completed menopause, this is quite normal. Women of childbearing age do not usually experience anovulation unless something has disrupted the body's hormone levels or damaged the ovaries.

For a normal couple without any possible reasons for infertility, the chances of conception are about 25 percent each month. Even when ovulation happens normally, there is no guarantee that the couple would conceive. When a woman is anovulatory, she cannot get pregnant because there is no egg to be fertilized. If a woman has irregular ovulation, she has fewer chances to conceive, since she ovulates less frequently. Adding to these woes, late ovulation does not produce the best quality eggs. This may also make fertilization less likely. Also, irregular ovulation means the hormones in the woman’s body are not right.

On a normal day, women with normal menstrual cycles experience the following symptoms,

  • increased amounts of cervical mucus
  • a drop and subsequent rise in resting body temperature in the middle of the menstrual cycle (around day 10-16)
  • periods that occur regularly

On the other hand, when there are abnormal levels of hormones, there might be the following changes,

  • Lack of fertile cervical mucus
  • Thinner or over-thickening of the endometrium (where the fertilized egg needs to implant)
  • Abnormally low levels of progesterone
  • A shorter luteal phase

Usually, women with anovulation will have irregular periods. In the worst case, they may not get their cycles at all. If one is having shorter cycles than 21 days, or longer than 36 days, one may have ovulatory dysfunction. If the cycles fall within the normal range of 21 to 36 days, but the length of your cycles varies widely from month to month, that may also be a sign of ovulatory dysfunction.

For example, if one month of the period is 22 days, and the next month’s cycle goes on till 35, that many variations between cycles could signal an ovulation problem. It is possible to get the cycles on an almost normal schedule and not ovulate, though this is not common. A menstrual cycle where ovulation doesn't occur is called an anovulatory cycle.

Main causes for anovulation include,

  • Obesity
  • Polycystic Ovarian Syndrome
  • Too low body weight
  • Extreme exercise
  • Hyperprolactinemia
  • Premature ovarian failure
  • Perimenopause, or low ovarian reserves
  • Thyroid dysfunction (hyperthyroidism)
  • Extremely high levels of stress

Once anovulation is detected, the doctor would order blood tests to check hormone levels. One of those tests might include a day 21 progesterone blood test. After ovulation, progesterone levels rise. If the tests figure out that the progesterone levels have not risen, one is probably not ovulating. The doctor may also ask for an ultrasound. The ultrasound will check out the shape and size of the uterus and ovaries, and also look to see if the ovaries are polycystic, which is a symptom of PCOS. Ultrasound can also be used to track follicle development and ovulation, though this isn't commonly done. In this case, you might have several ultrasounds over a one- to two-week period.

Different cases of anovulation demand different forms of treatment depending on the root cause. Some cases of anovulation can be treated by lifestyle change or diet. If the person has low body weight or if extreme exercise is determined as the cause of anovulation, the doctor is likely to prescribe gaining weight or lessening one’s exercise routine in order to get back to one’s usual menstrual cycle. The same goes for obesity. If one is overweight, losing even 10 percent of the current weight may be enough to restart ovulation.

The most common treatment for anovulation is fertility drugs. Usually, Clomid is the first fertility drug tried. If Clomid does not work, there are other fertility treatments left to try. If the inadequacy of ovarian reserve and egg quality is the reason for anovulation, then IVF treatment with donor eggs is prescribed. For women with PCOS, insulin-sensitizing drugs like metformin may help a woman start ovulating again. Six months of treatment is required before one gets to now if the metformin would work. Afterward, if metformin alone does not help, using fertility drugs in combination therapy has been shown to increase the chances of success of ovulation in previously anovulating women who did not respond to monotherapy. The cancer drug letrozole may be more successful at triggering ovulation in women with PCOS.

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