Anovulation

Gynaecologist and Obstetrician, Anovulation, Dr JFA Potgieter

The term “Anovulation” means lack of ovulation, or absent ovulation. Ovulation is the release of an egg from the ovary. This must happen in order to achieve pregnancy naturally. If ovulation is irregular, but not completely absent, this is called “oligoovulation”.

Both anovulation and oligoovulation are types of ovulatory dysfunction, which is a common cause of female infertility, occurring in up to 40 percent of infertile women.

Usually, women with anovulation will have irregular periods. In the worst case, they may not menstruate at all. If your cycle is shorter than 21 days, or longer than 36 days, you may have ovulatory dysfunction. If you cycle falls 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 your period is 22 days, the next it's 35, that much variation could signal an ovulation problem. It is possible to get your period on an almost normal schedule and not ovulate, though this isn't common. A menstrual cycle where ovulation doesn't occur is called an anovulatory cycle.

For a couple without fertility problems, the chances of conception are about 25 percent each month. Even when ovulation happens normally, a couple isn't guaranteed to conceive. When a woman is anovulatory, she can't 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. Late ovulation also produces lower quality eggs which may also make fertilization less likely and creates hormone irregularities.

These hormone irregularities can sometimes lead to other issues, including:

  • 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

Anovulation and ovulatory dysfunction can be caused by a number of factors. The most common cause of ovulatory dysfunction is polycystic ovarian syndrome (PCOS). Other potential causes of irregular or absent ovulation include:

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

In order to diagnose Anovulation, Dr. Potgieter will ask you about your menstrual cycles. If you report irregular or absent cycles, ovulatory dysfunction will be suspected. He might also ask you to track your basal body temperature at home for a few months.

Next, Dr. Potgieter will order blood work to check hormone levels. One of those tests might include a day 21 progesterone blood test.

After ovulation, progesterone levels rise. If your progesterone levels do not rise, you are probably not ovulating. Your doctor may also order a ultrasound. The ultrasound will check out the shape and size of uterus and ovaries, and also look to see if your ovaries are polycystic.

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.

Treatment will depend on the cause of the anovulation. Some cases of anovulation can be treated by lifestyle change or diet. If low body weight or extreme exercise is the cause of anovulation, gaining weight or lessening your exercise routine may be enough to restart ovulation. The same goes for obesity. If you are overweight, losing even 10 percent of your current weight may be enough to restart ovulation.

The most common treatment for anovulation is fertility drugs. For women with PCOS, additional insulin-sensitizing drugs like metformin may help a woman start ovulating again. If the cause of anovulation is premature ovarian failure, or low ovarian reserves, then fertility drugs are less likely to work. But that doesn't mean you can't get pregnant with your own eggs. Some women will be unable to conceive with their own eggs and may require IVF treatment with an egg donor.