What is anovulation?

Anovulation simply means not ovulating, and it is the #1 cause of female infertility. It can also cause menstrual cycle irregularities, such as no periods or amenorrhea, long or short cycles, or irregular cycles. If you want to get pregnant, you need to ovulate, have a regular menstrual cycle, and regular menstrual periods. 

How do you know if you are not ovulating?

Women who ovulate regularly have regular periods, usually every 28 days, with a normal range being anywhere from 21-35 days. Women who don't ovulate have very irregular periods or no periods at all. Monitoring your menstrual and ovulation cycles, which includes becoming aware of the signs of ovulation, can help you identify symptoms of anovulation, which include:

  • irregular basal body temperature (BBT)
  • irregular menstruation
  • reduced PMS symptoms
  • amenorrhea (the absence of a menstrual period)
  • excessive menstrual bleeding
  • oligomenorrhea (light menstruation)

What causes anovulation?

Anovulation is normal when you breastfeed or you are pregnant, in perimenopause, or adolescence.

  • The number one cause is so-called 'hyperandrogenic anovulation' such as polycystic ovary syndrome (PCOS).
  • Premature ovarian failure or aging
  • Women taking the birth control pill also do not usually ovulate, but they usually have regular menstrual cycles.
  • Stress-induced anovulation (SIA), often termed functional hypothalamic amenorrhea (FHA) or functional hypothalamic chronic anovulation
  • "Hypothalamic dysfunction" such as anorexia nervosa
  • Weight issues (being overweight or underweight) can lead to anovulation.
  • Thyroid disease such as hypothyroidism, not having enough thyroid hormone 
  • Hyperprolactinemia
  • Medications
  • Doctor induced (iatrogenic) eg radiation or chemotherapy
  • Hyperprolactinemia

Scroll down to learn why you may stop ovulating.

Can I identify why I don't ovulate?

It is important that any underlying cause of infertility which may result in anovulation be treated. In some cases, losing or gaining weight may help. In more serious cases, fertility drug therapies such as clomiphene and gonadotropin may be recommended to induce ovulation, or an ovarian wedge resection may be performed. This procedure involves the removal of certain parts of the ovaries in order to balance hormone levels. Speak to your doctor or a fertility specialist for information on what is best for you. Being aware of your options can help you make the appropriate decision for you.

What are the signs that I may not be ovulating?

  • If your periods do not come at all ( and you had a negative pregnancy test)
  • Your periods are more than 35 days apart
  • You have a lot of spotting with irregular periods
  • Some women have regular periods but are still not ovulating, but this is fairly unusual.

How can I determine if I am ovulating?

There are several ways to determine with enough certainty whether and when you are ovulating:

Basal body temperature (BBT) 

The least expensive way is to track your basal body temperature.  You will need a thermometer.  They do make special BBT thermometers, but a digital thermometer will also do. Don't use ear thermometers as they can vary depending on how far into your ear you push the probe, and you want a very accurate temperature.  

First thing in the morning, before you have gotten out of bed or done anything, take your temperature. Plot it on the graph or download an app to record each day. Do this every morning from the first day of your period until the first day of your next period.  If you are ovulating, you will find that your temperatures hover around the same number until about 14 days from your next period.  They will then dip down for a day, go up to a new temperature, and then hover around that new higher temperature until you get your next period. If you can see that on your graph, then you are ovulating. The dip is the day you are ovulating. If you cannot see that, you may not be ovulating. It can be hard to interpret these sometimes, so if you don't see the dip, don't get discouraged. Try another method.

Ovulation predictor kit (OPK)

Ovulation predictor kits look just like the home pregnancy tests but they determine when you are ovulating instead. Unfortunately, different brands vary in their accuracy. If you are finding positive tests with the regular "pee-on-the-stick" kind, then you don't really need the fertility monitor. If you are not having luck with the stick version, then the monitor may be helpful.  If you find a positive test, then you are almost definitely ovulating, though there are "false positive" OPK tests.  If you get your period 13-16 days after the positive test, then you are definitely ovulating.  

If you do not get your period in that time frame (and you are not pregnant), then you may have PCOS. PCOS can give you false-positive ovulation tests. Ten percent of ovulating women will not get positive ovulation tests, so if you are having regular cycles but can't find a positive ovulation test, you may still be ovulating. 

Blood progesterone levels

The ultimate way to determine whether you are ovulating or not is to get a blood test to check your progesterone level.  Progesterone is a hormone that your ovaries make after you ovulate.  The best way to test your progesterone level is to draw the blood about a week before your next period is due. If your progesterone level is over 3 ng/ml, then you are ovulating. If your cycles are too irregular to predict when your next one is coming, then it can be drawn 3 weeks or more after your last one.

What causes you to stop ovulating?

There are three distinct parts of the body that contribute to ovulation problems: the hypothalamus, the pituitary gland, and the ovaries.

Hypothalamic problems (GnRH pulses FSH and LH)

  • Polycystic ovary syndrome (PCOS)
  • Prepubertal
  • Strenuous exercise
  • Certain diets
  • Stress
  • Low BMI, anorexia, sudden weight loss
  • Chronic or severe illnesses
  • Certain drugs (e.g., opiates)

Pituitary causes

  • Hypothyroidism
  • Hyperthyroidism
  • Too much prolactin. Prolactin may be increased with certain drugs (e.g. major tranquilizers). Any pressure on the gland such as certain tumors (prolactinomas) can also cause a rise in the prolactin hormone (hyperprolactinemia), which in turn can cause problems with ovulation.

Ovarian causes

  • Premature ovarian failure (POF)
  • Ovarian failure = menopause
  • Primary ovarian failure (often a chromosomal problem)
  • Secondary ovarian failure (cause often unknown, but can be due to an autoimmune disorder or caused by chemotherapy, radiotherapy, or surgery. The FSH is usually increased as there is no estrogen.

Polycystic ovarian syndrome (PCOS)

A common reason for not ovulating is PCOS or polycystic ovarian syndrome, a condition where eggs cannot mature enough to be able to ovulate.  These semi-mature eggs produce a lot of testosterone and other male hormones.  These male hormones feedback to the pituitary (the gland in your head that controls your menstrual cycle), and they confuse your pituitary.  Your confused pituitary sends out the wrong hormones to the ovaries (too much LH and not enough FSH), and keep your ovaries from being able to ovulate.  This causes more testosterone production and the cycle just gets worse and worse.  All the sacs with the stuck eggs look like cysts on the ovaries, which is why it's called "polycystic".  

Many but not all women with PCOS usually have other signs of high testosterone levels such as acne, hair growth on the face, chest, back or belly, and male-pattern balding.

It is called a syndrome rather than a disease, because what causes it can vary from woman to woman.  One of the main causes is insulin resistance.  This is a condition where a woman's insulin is not working correctly and can lead to diabetes.  The ovary has insulin receptors.  When it sees too much insulin, it stops ovulating and makes male hormones and therefore PCOS.  Women with this condition oftentimes (about 50% of the time) are overweight, and many also have a family history of adult-onset diabetes in her older relatives.  PCOS needs to be diagnosed by your doctor and blood test and an ultrasound should be performed.

Premature ovarian failure 

Premature ovarian failure (POF) is a loss of ovarian function in younger women, well before menopause. Women with POF have eggs that are less or not capable to become fertilized. POF is among the reasons women have difficulties getting pregnant. It is often diagnosed by finding an elevated FSH test.

Thyroid disease

Both underactive or overactive thyroids resulting in hypothyroidism and hyperthyroidism can affect ovulation.  Other symptoms of thyroid disease include feeling hot when everyone else is cold or vice versa, unexplained weight gain or loss, hair loss, fatigue, nervousness, or skin changes. Thyroid disease is diagnosed by blood tests.


A less common reason for not ovulating is an excess of a hormone called prolactin. Prolactin is the hormone involved in breastfeeding, and many women with high prolactin levels will also have a milky discharge from the breasts, too.  Just like breastfeeding women do not get regular periods, women with high prolactin levels who are not breastfeeding will do the same. 

Breastfeeding moms

When a mother is breastfeeding, the hormones that trigger ovulation are often suppressed. This is a natural body reaction to giving birth. The body will try to prevent further pregnancy until the baby has stopped nursing. While ovulation does not cease and women do have the ability to become pregnant immediately after birth in some cases, ovulation problems may occur as long as breast milk is being produced.

Stress, exercise, and weight

Extreme stress or excessive dieting or exercise can also lead to ovulation problems, as can being overweight. Your optimal BMI body mass index should be between 19.5 and 25.  A woman's body is designed to decrease her fertility if it thinks there isn't enough food around to support a pregnancy/baby or if there is too much stress.  So if a woman has very low body fat or low dietary fat intake or is under extreme stress, she will stop ovulating.  This is common with marathon runners, ballet dancers, women on death row, and body-builders.  It can definitely happen in less extreme cases, too.  Decreasing the amount of exercise, increasing calorie and especially fat intake, or changing the stressful situation can reverse the ovulation problems.

Unknown causes of anovulation

About 10% of women who do not ovulate have no defined reason why they are not ovulating.  It appears that their pituitaries just do not send out the right signals.  There are also other rarer hormonal causes. Most of these will have other signs and symptoms that bring that person to the attention of a doctor.

No matter why you are not ovulating, you need to see a doctor.  If the lining of the uterus does not shed with a period at least every 6 weeks, it can start to turn abnormal, and can even turn into cancer.

Read More:
Progesterone and Pregnancy
Ovulation Calculator
Egg-White Cervical Mucus and Fertility