Ovulation bleeding is vaginal bleeding during or immediately before or after ovulation, which occurs roughly in the middle of a menstrual cycle. A person may also experience light spotting around this time.

Changes in estrogen levels often cause this type of bleeding, and light spotting around ovulation does not usually signal a serious problem. Some people refer to ovulation bleeding as estrogen breakthrough bleeding.

This article explains ovulation bleeding and other types of bleeding between periods. It also discusses when to contact a healthcare professional.

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Ovulation bleeding generally refers to bleeding or spotting that occurs around ovulation, which is when the ovary releases an egg.

In the days before to ovulation, estrogen levels steadily rise. After the release of an egg, the estrogen levels dip, and progesterone levels begin to increase.

This shift in the balance between estrogen and progesterone levels can cause light bleeding, which is usually much lighter than a regular period.

Typically, it does not cause any other symptoms.

If a person experiences other symptoms, such as cramping, alongside the bleeding or it lasts longer than a few days, it may indicate an underlying issue other than ovulation bleeding.

People who do not regularly ovulate may have unusual bleeding patterns, such as very light bleeding for many days or only getting a period every few months. Various medical conditions, including polycystic ovary syndrome (PCOS) and endometriosis, can cause irregular cycles.

Some ways to help identify whether ovulation is causing spotting or bleeding include:

  • On average, ovulation occurs 14 days after the last period begins, although many people ovulate earlier or later. To help pinpoint the time of ovulation, people can use ovulation testing kits or monitor their basal body temperature.
  • The bleeding occurs only once during each month at around the same time.
  • The bleeding stops within a couple of days and is not heavy or painful.

Learn more about when people ovulate.

Ovulation bleeding is just one type of atypical vaginal bleeding. While bleeding due to ovulation is usually not cause for concern, it is important to ensure that there is no underlying medical cause.

Implantation bleeding

After a sperm fertilizes an egg, the egg must implant in the lining of the uterus. Some people experience light bleeding or spotting 1 to 2 weeks after implantation.

According to the National Health Service (NHS) in the United Kingdom, implantation generally occurs 5 to 6 days after ovulation.

Learn more about implantation bleeding.

Pregnancy-related bleeding

Bleeding during the first trimester occurs in around 15 to 25 of every 100 pregnancies.

While bleeding early in pregnancy is not uncommon, it can be a sign of an issue with the pregnancy. This may include miscarriage or ectopic pregnancy. These issues are more common during the first 12 weeks of pregnancy.

Later in pregnancy, bleeding may be a sign of early labor. It can also be an indication of:

Learn more about spotting in early pregnancy.

Anovulatory cycles

Anovulatory cycles are monthly cycles during which a person does not ovulate. This can be due to various issues and conditions, including:

Irregular bleeding is common during an anovulatory cycle.

Structural abnormalities

Structural problems with the uterus or ovaries may cause unusual bleeding. For example, a person with endometriosis or uterine polyps may bleed between cycles.

Learn more about bleeding between periods.

Thyroid issues

The thyroid releases hormones that help regulate the menstrual cycle. Too much or too little thyroid hormone can cause bleeding between periods.

Hormone treatments

Various hormones, including birth control pills and fertility drugs, may cause bleeding between cycles.

Pituitary diseases

The pituitary gland helps regulate hormones that affect the menstrual cycle, including estrogen and progesterone. Conditions that affect the pituitary gland, such as Cushing disease, may cause atypical bleeding.

Infection

Sexually transmitted infections (STIs), such as gonorrhea or chlamydia, may cause the cervical tissue to become inflamed and bleed easily.

Tumors

Ovarian tumors, especially those that produce estrogen, may cause unusual bleeding. Although rare, abnormal bleeding may be a symptom of cervical or endometrial cancer.

In people with highly irregular cycles, it can be difficult to tell the difference between atypical bleeding and the typical monthly period. Anyone whose periods do not follow a predictable pattern should speak with a healthcare professional.

Light spotting in the middle of the cycle is not generally cause for concern, especially if it occurs at the same time each month.

However, it is important to discuss any unusual bleeding with a healthcare professional, particularly if other symptoms occur alongside it. Charting the bleeding — including what time it usually occurs and how long it lasts — can help a healthcare professional identify the cause.

People who experience the following should contact a healthcare professional:

  • changes in the usual pattern of bleeding, for example, periods being less than 24 days or more than 38 days apart
  • bleeding becoming much heavier or lighter than usual
  • excessive bleeding, such as soaking a tampon or pad every 2 hours or passing large blood clots
  • additional symptoms, such as:
    • painful periods
    • difficulty getting pregnant
    • pelvic pain during or after sex
    • shortness of breath
    • lightheadedness or dizziness
    • chest pain
  • bleeding after menopause

A person should seek urgent medical attention if:

  • they have had a positive pregnancy test or believe that they are pregnant
  • the bleeding is extremely heavy, soaking through a large pad or tampon every hour
  • they develop a fever or other symptoms of an infection
  • they have a bleeding disorder and experience heavy bleeding that does not stop

It is fairly common for individuals to experience some light bleeding or spotting during ovulation.

While ovulation bleeding is a common reason for bleeding between periods, it is not the only potential cause. Therefore, it is important to monitor the bleeding and speak with a healthcare professional about any bothersome symptoms.

As everyone’s menstrual cycle can be different, a person may wish to track their cycle to determine the usual cycle length and the typical day of ovulation. This information can often help a healthcare professional determine whether ovulation or something else is causing the bleeding.

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