If your periods are irregular or you're trying to get pregnant, you might hear the word anovulation.
Anovulation, also called an anovulatory cycle, happens when your ovary doesn’t release an egg during your period. It is a common cause of infertility and causes about 30% of fertility problems in women.
If you want to get pregnant or have irregular periods, keep reading to learn more about the causes, signs and options for treatment.
What is anovulation?
To understand anovulation, it helps to first understand how your menstrual cycle works. In a normal menstrual cycle, your brain sends signals to your ovaries, which then help an egg mature and get released. This process is called ovulation.
“Ovulation usually happens about 14 days after the start of menstruation,” said Adedayo Onibokun, MD, a gynecologist with Banner Health. “During this time, an egg is released from the ovary after a coordinated rise in hormone levels, including follicle-stimulating hormone (FSH) and luteinizing hormone (LH).”
If sperm are present, they can fertilize the egg that is released, which can lead to pregnancy. But if ovulation doesn’t happen, the egg stays in the ovary and isn’t released. This is called anovulation or “no ovulation.” Without an egg being released, the chances of getting pregnant are basically zero.
Signs and symptoms of anovulation
Sometimes, you might not realize you aren’t ovulating unless you're trying to get pregnant. Sometimes, you may have clear signs.
“Anovulation usually causes irregular periods or no periods at all (amenorrhea),” Dr. Onibokun said. “Your cycle might be shorter than 21 days, longer than 35 days or you might miss your period for several months.”
Other signs include:
- Very light or very heavy bleeding
- No cervical mucus changes
- Mood swings, fatigue or low sex drive (libido)
- Trouble tracking ovulation with apps or ovulation predictor kits
- Trouble getting pregnant
What causes anovulation?
“The menstrual cycle is a well-regulated system that is controlled by the hypothalamus, pituitary gland and ovaries,” Dr. Onibokun said.
Here’s how it works:
- The hypothalamus releases gonadotropic-releasing hormone (GnRH)
- GnRH signals the pituitary gland
- The pituitary releases FSH and LH
- FSH and LH stimulate the ovaries
- The ovaries produce estrogen and progesterone
If any part of this chain is disrupted, ovulation may stop. Here are the most common causes.
Polyendocrine metabolic ovarian syndrome (PMOS)
PMOS, formerly known as PCOS, is the leading cause of anovulation. It changes hormone levels and stops eggs from maturing and being released regularly. Many people with PMOS can restore ovulation with lifestyle changes or medication.
Thyroid disorders
Your thyroid controls metabolism and hormone balance. Both hypothyroidism (underactive) and hyperthyroidism (overactive) can affect ovulation. Blood tests can detect thyroid problems and medication often corrects them.
Stress
Chronic stress impacts the hypothalamus, a part of your brain that manages reproductive hormones. Severe stress can delay or stop ovulation.
Over-exercising
Doing intense exercise for a long time can cause your brain to stop producing hormones, which can lead to anovulation.
Being underweight or overweight
Body fat also produces estrogen. If you have too little body fat, you might not ovulate. If you have too much, it can throw off your hormones.
“Women with high BMI have excess adipose tissue or body fat,” Dr. Onibokun said. “This excess tissue can produce extra estrogen that affects the menstrual cycle and can prevent ovulation.”
Even a 5% to 10% change in weight can sometimes restart ovulation.
Perimenopause
As you approach menopause, ovulation becomes less regular. Anovulatory cycles become more common during this time.
Certain medications
Some medications can affect hormone levels, including:
- Steroids
- Chemotherapy
- Certain antidepressants or antipsychotics
- Hormonal contraceptives
How is anovulation diagnosed?
If you think you might not be ovulating, your health care provider may recommend:
- A review of your menstrual history
- Blood tests to measure hormone levels (progesterone, LH, FSH, thyroid-stimulating hormone (TSH), prolactin)
- Progesterone testing after your expected ovulation
- A pelvic ultrasound to look at your ovaries and uterine lining
Progesterone levels go up after ovulation. If your progesterone stays low, it might mean you didn't ovulate.
Tracking ovulation at home with ovulation predictor kits or basal body temperature charts can also give helpful information.
Treatment options for anovulation
Treatment depends on the cause and your fertility goals
Lifestyle changes
If weight, stress or lifestyle factors are contributing, your provider may suggest:
- Losing extra weight
- Gaining weight, if needed
- Eating healthy meals
- Exercising often
- Getting better sleep
- Managing stress
“If you want cycle control but don’t want to get pregnant, hormonal birth control pills, patches or rings can regulate bleeding and protect the uterine lining,” Dr. Onibokun said.
Medications to induce ovulation
Your provider may recommend medications to help your body release an egg.
Common ovulation-inducing drugs include:
- Clomiphene citrate (Clomid)
- Letrozole (Femara)
- Injectable hormone (FSH, GnRH agonist, human chorionic gonadotropin (hCG))
These medicines are often used by people with PMOS who want to get pregnant but they can also help others who don’t ovulate. Your health care provider will watch you closely to lower the chances of having more than one baby at a time.
Treating underlying hormone conditions
If thyroid problems or high prolactin levels are causing anovulation, medication can restore balance and restart ovulation.
Advanced fertility treatments
If lifestyle changes and medication don’t help treat your anovulation, your provider may refer you to a fertility specialist or reproductive endocrinologist.
Other fertility options may include:
- Intrauterine insemination (IUI)
- In vitro fertilization (IVF)
These treatments can improve your chance of conception.
Why treatment matters
Ongoing anovulation can lead to problems over time. Without regular progesterone, the lining of the uterus can become too thick. This can increase the risk of endometrial hyperplasia (abnormal thickening of the uterine lining). In rare cases, it might lead to uterine cancer.
Treating anovulation early can stop problems and improve your reproductive health. See your health care provider if:
- You haven't had a period in three months
- Your periods are very irregular
- You have very heavy or long-lasting bleeding
- You've been trying to get pregnant for 12 months (or six months if you're over 35)
Takeaway
Anovulation happens when your ovary does not release an egg. It is common and can happen for many reasons. You might notice irregular periods, heavy bleeding or trouble getting pregnant.
The good news is that treatment and lifestyle changes can often help restore ovulation. With the right guidance, many women with anovulation have regular periods, better hormonal balance and successful pregnancies.
If your periods are unpredictable or if you’re worried about your fertility, make an appointment with your health care provider or a Banner Health specialist.
