What is Anovulation?
Anovulation means lack of ovulation, or absent ovulation. Ovulation, which is the release of an egg from the ovary, must happen in order to achieve pregnancy. If ovulation is irregular, but not completely absent, this is called oligovulation. Both anovulation and oligovulation are kinds of ovulatory dysfunction.
Ovulatory dysfunction is a common cause of female infertility, occurring in up to 40% of infertile women.
What are the Symptoms of Anovulation or Ovulatory Dysfunction?
Usually, women with anovulation will have irregular periods. Or, in the worst case, they may not get their cycles at all. If your cycles are shorter than 21 days, or longer than 36 days, you may have ovulatory dysfunction.
Also, if your 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, one month your period is 22 days, the next it's 35.)
It is possible to get your cycles 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.
How Does Anovulation and Ovulatory Dysfunction Cause Infertility?
For a couple without infertility, the chances of conception are about 25% each month. So even when ovulation happens, 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. Plus, it seems that late ovulation doesn't produce the best quality eggs, which may also make fertilization less likely.
Also, it's important to remember that irregular ovulation means the hormones in the woman's body aren't quite right. These hormonal irregularities can sometimes lead to other issues, like lack of fertile cervical mucus, thinner or over thickening of the endometrium (where the fertilized egg needs to implant), abnormally low levels of progesterone, and a shorter luteal phase.
What Causes Anovulation?
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:
- Too low body weight
- Extreme exercise
- Premature ovarian failure
- Perimenopause, or low ovarian reserves
- Thyroid dysfunction (either hyperthyroidism or hypothyroidism)
- Extremely high levels of stress
How is Anovulation Diagnosed?
Your doctor will ask you about your menstrual cycles, and if you report irregular or absent cycles, ovulatory dysfunction will be suspected. You doctor might also ask you to track your basal body temperature at home for a few months.
Next, your doctor 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.
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.
What are the Potential Treatments for Anovulation?
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% of your 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. Clomid can trigger ovulation in 80% of anovulatory women, and help about 45% get pregnant within six months of treatment. If Clomid doesn't work, there are many other drugs worth trying.
- All About Fertility Drugs
- All About Clomid
- Clomid Success
- Gonadotropin Treatment
- IVF Procedures, Risks, Costs, and Success Rates
For women with PCOS, insulin sensitizing drugs like Metformin may help a woman start ovulating again. Usually, six months of treatment is required before you'll know if the Metformin will work. If Metformin alone doesn't help, using fertility drugs in combination has been shown to increase the chance of success in women who didn't ovulate on fertility drugs alone.
If the cause of anovulation is premature ovarian failure, or low ovarian reserves, then fertility drugs are less likely to work. Because of the low success rate, some (but not all) doctors will refuse to treat women with fertility drugs if they have a diagnosis of low ovarian reserves. In that case, your doctor may suggest using an egg donor, or an alternative family building option like adoption.
More on infertility symptoms and getting help:
- I Can't Get Pregnant. What Now?
- Quiz: Do I Have Infertility Symptoms?
- Take a Fertility Quiz
- When Should You Seek Help for Getting Pregnant?
- Talking to Your Doctor About Getting Pregnant
- Fertility Specialists: Who They Are and How They Can Help You
- Finding the Best Fertility Clinic for You
- Why Can't I Get Pregnant if I'm Healthy?
- How to Have a Baby When You've Been Trying for Awhile
- What to Expect During Fertility Testing
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Infertility. National Library of Medicine: MedlinePlus. Accessed November 5, 2008. http://www.nlm.nih.gov/medlineplus/infertility.html
Infertility in Women. A.D.A.M. Healthcare Center. Accessed November 5, 2008. http://adam.about.net/reports/Infertility-in-women.htm
Medications for Inducing Ovulation: A Guide for Patients. American Society of Reproductive Medicine. Accessed November 5, 2008. http://asrm.org/uploadedFiles/ASRM_Content/Resources/Patient_Resources/Fact_Sheets_and_Info_Booklets/ovulation_drugs.pdf
Patient Fact Sheet: PCOS. American Society of Reproductive Medicine. http://asrm.org/uploadedFiles/ASRM_Content/Resources/Patient_Resources/Fact_Sheets_and_Info_Booklets/PCOS.pdf