Anovulation at a glance
- Anovulation is the lack or absence of ovulation (the release of an egg). It is a common cause of infertility.
- Anovulation is often the result of an imbalance of the hormones that cause a woman to ovulate and may be part of the condition polycystic ovary syndrome (PCOS).
- Irregular menstruation can also indicate anovulation, and we have a variety of diagnostic tools to help determine the cause of irregular cycles.
- Depending on the severity and cause, treatment options for anovulation can include lifestyle changes, medication or even in vitro fertilization (IVF).
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What is anovulation?
Anovulation occurs when an egg does not release, or ovulate, from a woman’s ovaries. Chronic anovulation is a common cause of infertility. According to the National Institutes of Health, these conditions account for almost 30 percent of female infertility.
Anovulation is typically, although not always, coupled with irregular or lack of menstruation. However, with anovulatory cycles, there may be bleeding, which a woman may mistake for a normal menstruation, although this would only rarely occur on a regular, monthly basis.
How ovulation works
Ovulation begins to happen when the hypothalamus (a gland in the brain) secretes gonadotropin-releasing hormone (GnRH), which then causes the pituitary gland (another gland in the brain) to release follicle stimulating hormone (FSH) and luteinizing hormone (LH).
FSH stimulates the woman’s eggs (follicles) that then make the hormone estrogen, which builds the uterine lining. Next comes the release of LH (“LH surge”), which serves to release the egg from the ovary and into the fallopian tube.
At this point, fertilization by the male’s sperm must take place within 12-24 hours, or the egg will no longer be viable. If fertilization occurs, the embryo will reach the uterus and attach to the wall of the uterus in about five days after ovulation, establishing a pregnancy.
If fertilization does not take place, the progesterone levels will decrease and the uterine lining will shed with a menstrual period.
Causes of anovulation
If the ovulation process is interrupted, this results in anovulation. Ovulation is a complex process, which involves many glands and organs and for chemicals to be sequentially released. So there are many different things that can cause anovulation.
Some common causes of anovulation follow.
- Obesity: A high BMI, or body mass index, can cause a chemical imbalance to occur when there is an excess of androgens such as testosterone.
- Stress: Excessive stress or anxiety can cause GnRH, LH and FSH to become imbalanced.
- Low body weight and/or excessive exercise: A low BMI or regular intense physical exercise can negatively impact the woman’s pituitary gland. This may cause the pituitary gland to not produce enough LH and FSH.
- Abnormalities of TSH and/or prolactin: Thyroid stimulating hormone (TSH) and prolactin are two hormones released by the brain. Imbalances in either one of these can interfere with ovulation.
- Polycystic ovary syndrome (PCOS): PCOS is a common disorder that affects about 1 in 10 women of childbearing age in the United States and can result in anovulation. It is considered the most common hormonal imbalance for women of reproductive age. PCOS causes the woman’s body to make an excess of male hormones, including testosterone. With those high levels of androgens (male hormones), the ovaries’ follicles containing the eggs remain small. This syndrome is marked by small, typically painless, cysts on the ovaries. Other symptoms may include acne and hirsutism, or excessive hair growth, particularly around the upper lip and chin.
- First and last periods: Anovulation and abnormal bleeding often occur when a girl first begins her menstruation. It also can occur during perimenopause, when a woman is in her mid-40s and approaching the menopause. During both of these transitional periods, anovulatory cycles are caused by hormonal imbalances.
The most defining feature in diagnosing anovulation is simply the absence of regular menstruation. Other tests that may be performed during the evaluation include:
- Testing blood progesterone levels.
- Testing blood thyroid and prolactin levels.
- Ultrasound exam of the pelvic organs.
- Other tests may be recommended, such as testing the lining of the uterus or other blood tests, depending on the woman’s evaluation and history.
Generally, if a woman menstruates on a regular schedule, especially with the accompanying symptoms of bloating, mood change or breast tenderness, she is ovulating. Ovulation predictor kits can identify the LH spike that occurs with ovulation. Although not commonly used, basal body temperature charting (testing body temperature daily to identify the rise associated with ovulation) is another option to identify ovulation. A physician can also check for ovulation by testing the serum progesterone levels.
Lifestyle modifications can be the first step for overcoming anovulation.
- For women struggling with obesity or a high BMI, we recommend they make changes to be at a healthier weight. This can be very difficult in women with anovulation, and support such as nutritional counseling may be helpful.
- For women with a low BMI (very low body weight), nutritional counseling can also help.
- For those where significant exercise is the cause of the anovulation, modifying those habits is optimal.
- Similarly, in women with high stress help with stress management may be beneficial.
Many fertility diets have been proposed. Ultimately, the best fertility diet is the one a woman can maintain over the long term. Many women try a challenging diet, lose a few pounds, but are unable to keep on the diet. Social support (talking to others, sharing recipes and tips) can be very helpful during this time.
Similar to a practical diet that can be maintained, a “real world” exercise program is beneficial. Again, social support such as going on walks together, going to the gym together, and similar group activities may make the activities more likely to be sustained.
We often recommend medical treatments in tandem with lifestyle modifications. Medications such as clomiphene citrate, aromatase inhibitors, insulin-sensitizing agents or gonadotropins may be prescribed. IVF or intrauterine insemination (IUI) may be recommended to have a baby in certain circumstances.