Abnormal vaginal bleeding between periods is also called intermenstrual bleeding, spotting, and metrorrhagia. When bleeding occurs between normal periods, there are many possible causes.

While some causes may be easy to treat, others can indicate a serious underlying condition. Whether you notice spotting or heavier bleeding between periods, it’s important to see your doctor for testing, diagnosis, and treatment options. Potential causes of bleeding between periods include:

• a growth in your uterus or cervix
• stress
• a change in medication
• a miscarriage
• vaginal dryness
• a hormone imbalance
• cancer

Bleeding between periods isn’t a normal part of the menstrual cycle.

The average cycle lasts 21 to 35 days. Normal vaginal bleeding, also known as your period, can happen for a few days to a week. Any bleeding outside of this is considered abnormal and can be caused by a variety of factors. These include:

1. Hormonal imbalance

Estrogen and progesterone are the two hormones that regulate your cycle. You may have spotting if they get out of balance. The following can all affect your hormone balance:

• dysfunctional ovaries
• thyroid gland problems
• starting or stopping birth control pills

As well, some women spot during ovulation as a result of hormonal changes.

When starting any type of hormonal contraceptive, abnormal bleeding is common during the first three months, according to the National Health Services of the United Kingdom. These contraceptives include:

• birth control pills
• intrauterine device
• contraceptive patch
• contraceptive implant or injection

2. Pregnancy complications

Complications during pregnancy can cause spotting. Both a miscarriage and an ectopic pregnancy can cause bleeding. An ectopic pregnancy occurs when a fertilized egg implants itself in the fallopian tubeinstead of the uterus.

Spotting during pregnancy may not mean you’re having a miscarriage. However, if you’re pregnant and experience any vaginal bleeding, you should contact your doctor immediately.

3. Uterine fibroids

Uterine fibroids are noncancerous growths that form in the uterus. They aren’t uncommon in women who’ve given birth.

4. Infection

Vaginal bleeding between periods may indicate an infection of your reproductive organs. Infection can cause inflammation and bleeding. Causes include:

• sexually transmitted infection
• vaginal douching
• intercourse
• pelvic inflammatory disease, which is marked by inflammation of the reproductive organs that leads to scarring

5. Cancer

Less commonly, a cancer of any of these organs can cause bleeding:

• cervix
• vagina
• uterus
• ovaries

6. Rare causes

Other possible causes of vaginal bleeding are rare and include:

• insertion of an object into the vagina
• extreme stress
• diabetes
• thyroid disorders
• significant weight gain or loss