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Late ovulation occurs when a person ovulates close to the onset of their next menstrual period. Late ovulation may affect a person’s fertility and menstruation.

Depending on the length of their menstrual cycle, most women will ovulate 10–16 days before their period. According to the Office of Women’s Health, the average length of a menstrual cycle is 28 days, but some cycles may last between 21-38 days.

People with more prolonged or irregular cycles tend to ovulate later, or they may not ovulate every cycle.

In this article, we discuss late ovulation and its effect on fertility. We list some potential causes of late ovulation and suggest when its time to see a doctor.

a woman looking stressed as she is experiencing Late ovulationShare on Pinterest
Extreme stress may affect a person’s menstrual cycle.

The following may contribute to late ovulation:

Polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is one of the most common causes of female infertility. It affects 6-12% of females of reproductive age in the United States.

Signs and symptoms of PCOS include:

According to the Centers for Disease Control and Prevention (CDC), treatment can improve a person’s ability to conceive and reduce the risk of complications, such as type 2 diabetes and heart disease.

Treatment options include medication, weight loss, and other lifestyle changes.

Learn more about PCOS here.


According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), hypothyroidism or an underactive thyroid occurs when the body does not produce enough thyroid hormones. Hypothyroidism can affect menstruation and inhibit ovulation.

The NIDDK indicate that approximately 4.6% of people in the U.S. aged 12 and older have hypothyroidism. Females are much more likely than males to develop the condition.

Medication can restore thyroid hormones to normal levels, which may regulate ovulation and improve fertility.

In one 2012 study of 394 infertile women, 23.9% had hypothyroidism. After treatment, 76.6% of those women conceived within 1 year.

Learn about the symptoms of hypothyroidism here.

Extreme stress

People experiencing extreme physical or emotional stress may stop ovulating or may experience other menstrual changes. Examples of extreme stressors include:

  • domestic or sexual violence
  • chronic or terminal illness, such as cancer
  • the death of a loved one
  • living through war
  • surviving a natural disaster

For example, an older 2009 study reports that the rate of menstrual disorders increased significantly in women in China who survived an earthquake that measured 8.0 on the Richter scale.

Find out more about stress and why it occurs.


When a person breastfeeds exclusively, the body naturally stops menstruating and ovulating.

Planned Parenthood defines exclusive breastfeeding as feeding the baby breast milk and nothing else at least every 4 hours during the day and every 6 hours at night.

As breastfeeding stops ovulation, some women use it as a form of birth control. However, it is not completely effective. Approximately 2% of those who follow this method will get pregnant within 6 months after the birth.

Normal menstruation and ovulation will typically resume once a person finishes breastfeeding or once their baby begins solid foods and breastfeeds less frequently.

Find out more about breastfeeding here.


According to a 2013 article in the Journal of Human Reproductive Sciences, hyperprolactinemia is a rare cause of late or missed ovulation. It occurs when the body produces higher-than-normal levels of prolactin, a hormone that stimulates breast milk production.

According to the article, the prevalence of hyperprolactinemia ranges from 0.4% in the general population to 5% in family planning clinics, to 17% in women with polycystic ovary syndrome (PCOS).

Hyperprolactinemia may result from a benign brain tumor or the use of some medications.

The article adds that treatment with medication can reduce prolactin production, shrink the tumor, eliminate symptoms, and facilitate normal ovulation.

Find out about testing prolactin levels in the blood here.


Some medications and illicit drugs can prevent ovulation. According to the Journal of Women’s Health, cannabis may have a relationship with ovulation disorder.

However, research into the impact of specific medications and substances on ovulation is ongoing, and researchers need to conduct further research to confirm any links.

Stopping the use of these substances or switching to an alternative medication may help to regulate ovulation. However, individuals should not stop or change medications without discussing it with their doctor first.

Late ovulation can affect a person’s fertility and ability to conceive.

The American College of Obstetricians and Gynecologists (ACOG) state that problems with ovulation, such as late or missed ovulation, are the most common causes of female infertility.

Women who have long or irregular cycles can struggle to know when they have ovulated. This makes conception challenging because they do not know when to time intercourse.

However, late ovulation does not make conception impossible. Many women with irregular ovulation will successfully conceive.

Ovulation predictor kits can help individuals determine when they ovulate, enabling them to more accurately time sexual intercourse.

A range of kits is available for purchase online.

Those who have a medical condition that affects ovulation, such as PCOS, hyperprolactinemia, or hypothyroidism, can often conceive following treatment.

Late ovulation may also affect menstruation.

Some people with late ovulation may have heavy bleeding during their period. According to the National Health Service (NHS) in the United Kingdom, this occurs because levels of the hormone estrogen rise during the first part of the menstrual cycle, causing the lining of the uterus to thicken.

Then, ovulation triggers the body’s release of another hormone, progesterone. This hormone supports the uterus to maintain a pregnancy, should one occur.

However, late or missed ovulation means that the body does not secrete progesterone. Instead, it continues to release estrogen, causing more blood to build up in the uterine lining.

At a certain point, the lining becomes unstable and leaves the body as a heavier-than-normal menstrual period.

Individuals should see their doctor if they have concerns about their menstrual cycle, ability to ovulate, or fertility.

In general, the earlier a person seeks treatment, the better the outcome. This is especially true about fertility, which, according to ACOG, declines with age.

It is also important to see a doctor if any of the following apply:

  • menstrual cycles are less than 21 days or longer than 40 days
  • sudden changes occur to the menstrual cycle
  • periods suddenly stop without any apparent reason
  • heavy menstrual bleeding occurs
  • severe period pains occur
  • symptoms of PCOS, hypothyroidism, or hyperprolactinemia develop
  • conception does not occur within 12 months of trying for those under 35 years of age, or within 6 months for those over 35

Late ovulation that occurs regularly may reduce a person’s fertility and cause heavy periods. However, late ovulation can occur in almost any woman occasionally. Infrequent late ovulation is not typically a cause for concern.

Common causes of late ovulation include stress, breastfeeding, and medical conditions, such as PCOS and hypothyroidism. In cases of stress and breastfeeding, changes to menstruation and fertility are typically only temporary.

In the case of an underlying medical condition, treatment can often restore normal ovulation and improve a person’s chances of conceiving.