When you're trying to get pregnant, you start paying more attention to your menstrual cycle than usual. And if you're having trouble getting pregnant despite having a cycle that appears normal, you may be wondering what's going on.
In a typical cycle, the hormones in your brain tell your body to prepare for the release of an egg. Then your egg is released from your ovary into the fallopian tubes. If the egg is fertilized within 12 to 24 hours after being released, it will attach to the wall of the uterus within 5 days, and you'll start growing a baby. If fertilization doesn't happen, you'll shed the uterine lining during your period.
Anovulation is anything that interrupts the ovulation process. Anovulation is responsible for about 30% of fertility problems in women.
What Causes Anovulation?
Anovulation is a complex process that involves a lot of organs, glands, and hormones, so there are a lot of potential causes. Some of these include:
Polycystic ovarian syndrome (PCOS). This is the most common cause of anovulation. PCOS causes women to ovulate irregularly or not at all. Sometimes PCOS is associated with elevated levels of testosterone, which can also cause excessive hair growth and acne.
Premature ovarian insufficiency (POI). This occurs when a woman's ovaries fail before she is 40. It's sometimes called premature menopause. Some medical conditions and exposures can cause POI, but for many women the cause is unexplained. About 5% to 10% of women with POI will conceive naturally and have a normal pregnancy.
Hypothalamus or pituitary gland dysfunction. These glands produce hormones that are responsible for ovulation. Anything that interferes with the normal function of these glands, such as a benign pituitary gland tumor, can cause anovulation.
Diminished ovarian reserve (DOR). At birth, women have all of the eggs they will ever produce. It's normal for a woman's egg supply to decrease over time. Women with DOR have fewer eggs remaining than normal. This can have medical, surgical, or congenital (present at birth) causes, or it can be unexplained. Women with DOR will produce fewer eggs with fertility treatments but may still be able to conceive naturally.
Functional hypothalamic amenorrhea (FHA). This condition can be caused by stress, excessive exercise, or low body weight. It is sometimes associated with anorexia, an eating disorder.
Menopause. This is a naturally occurring decline in ovarian function that happens around the age of 50. Menopause is defined as not having had a period in one year. Some women experience other symptoms as well, such as hot flashes, difficulty sleeping, and mood changes.
What Are the Symptoms of Anovulation?
Sometimes there are no symptoms of anovulation. Having normal menstrual cycles doesn't always mean that ovulation is occurring. However, some symptoms of anovulation can include:
- Not having periods
- Not having cervical mucus
- Excessive bleeding with periods
- Light bleeding with periods
- Irregular basal body temperature (BBT)
How Is Anovulation Diagnosed?
Your doctor will listen to your symptoms and history and perform a physical exam. They may also do some tests and imaging studies, including:
- Pregnancy test
- Tests of certain hormone levels
- Thyroid tests
- Glucose tolerance test
- Vaginal ultrasound
Depending on the results of your exam, other tests may be needed, such as testing the lining of the uterus.
How Is Anovulation Treated?
The treatment for anovulation will depend on the cause. For some women, lifestyle modification may be enough. Others may need medical or surgical treatments.
Lifestyle modification. Diet and exercise changes can be helpful for women whose anovulation is caused by either a high or low body mass index (BMI). In either case, nutritional counseling may help. Women whose anovulation is caused by excessive exercise will benefit from exercising less, while women with a high BMI may benefit from exercising more. If stress is causing anovulation, stress management and relaxation techniques may help.
Medicines. Ovulation induction is the use of fertility medicines to treat anovulation. This can also be used on women who are ovulating to increase the chances of pregnancy. Most pregnancies occur within three cycles of this treatment. Commonly prescribed medications include:
- Clomiphene citrate. Approximately 80% of people who take this medicine will ovulate and approximately 40% will become pregnant.
- Human chorionic gonadotropin (hCG). This is often added to clomiphene citrate or follicle-stimulating hormone treatments. HCG causes the ovary to release an egg and helps time inseminations. It will also cause false positives in pregnancy tests.
- Follicle stimulating hormone (FSH). FSH may be used in women who either don't make their own FSH or who don't become pregnant on clomiphene citrate. It can also be used on women who do ovulate to increase the chance of pregnancy.
- GnRH agonists and antagonists. These are synthetic hormones that are used to control the release of luteinizing hormone (LH). This prevents the spontaneous release of an egg during fertility treatments.
Surgery. If you have PCOS that doesn't respond to other treatments, your doctor may do a procedure called ovarian drilling. This is a minimally invasive procedure that is done laparoscopically, which means it is done with small incisions with the aid of a tiny camera. Ovarian drilling works by making small holes in the ovaries. This reduces the amount of testosterone that the ovaries produce. Lowering the amount of testosterone can help the ovaries produce an egg every month and start regular menstrual cycles.