What You Should Know About Abnormal Uterine Bleeding

Heavy menstrual bleeding or abnormal bleeding between your periods can occur at any time during the reproductive years, and it is not usually concerning. In most cases, red, brown, or black menstrual blood clots are bits of the endometrium (the lining of the uterus) that are shed during menstruation.

But there are times when menorrhagia is a sign of a problem. Here's what you should know about abnormal uterine bleeding, including what may be causing the heavy flow and how it can be treated.

A pile of tampons on a table
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What's considered heavy bleeding during menstruation? If you're finding you need to change your pad or tampon more often than every hour or so, or if you're having a period that's been going on for seven days or more, then you may be experiencing abnormal bleeding.

Heavy uterine bleeding can be frequent or intermittent, depending on the cause. You might also experience bleeding between your periods.

During perimenopause, which can last for several years before menopause, menstrual bleeding can be irregular. It is usually lighter than usual, but some people can occasionally experience heavy bleeding. And after menopause—defined as at least 12 consecutive months without a period—any bleeding is considered abnormal and should prompt a visit to the healthcare provider.

When to See a Healthcare Provider

You should see a healthcare provider urgently for your menstrual bleeding if:

  • You are pregnant.
  • Heavy bleeding lasts for more than 24 hours.
  • You are postmenopausal.


There are several causes of abnormal menstrual bleeding. It can happen if you have a hormonal imbalance, an infection, or a structural problem. Sometimes a growth or a tumor in the female reproductive system can cause bleeding.

Common causes include:

Bleeding During Pregnancy

Generally, bleeding during pregnancy requires medical attention. It can signal a problem, such as an impending miscarriage.

During the very early stage of pregnancy, however, you might have light bleeding for just a few hours, and you could see trace blood for up to a day. This is implantation bleeding, and it can occur as the embryo (the fertilized egg) attaches to the uterus. If you are concerned or if you also have cramps with your bleeding, call your healthcare provider.

Hormone Treatment

Hormone treatment may be used for managing conditions such as cancer, and many types of contraceptives include hormones.

People who use oral contraceptives or who have an intrauterine device (IUD) also sometimes have excessive or prolonged periods. If you experience excessive uterine bleeding while using an IUD, it should be removed and you should talk to your healthcare provider about trying another birth control method.

Bleeding Problems

Heavy menstrual bleeding can also happen due to a bleeding disorder or from taking blood thinners.

Blood thinners include prescription therapies that are often used to prevent vascular events. Many over-the-counter non-steroidal anti-inflammatories (NSAIDs) used to manage mild to moderate pain can cause bleeding as well.

Disorders of the platelets, such as von Willebrand's disease, are the most common blood disorders that cause excessive menstrual bleeding. These usually are diagnosed soon after a young person starts getting their period.

Adults who have von Willebrand's disease will also commonly experience nosebleeds, easy bruising, and blood in the stool.


Your healthcare provider will begin an evaluation in order to figure out what's causing you to have heavy menstrual bleeding.

You might have:

  • A pelvic exam
  • A Pap smear
  • Lab tests, which may include blood tests and a urine test
  • If appropriate, a pregnancy test
  • A pelvic ultrasound

You might need to have an endometrial biopsy, dilation and curettage (D&C), or hysteroscopy to further evaluate the condition of your uterus.

If you experience abnormal bleeding or excessive bleeding on a regular basis, you should be monitored closely to make sure your iron levels don't dip. If that happens, you may need to take iron supplements.


Often, severe pain and cramping can be treated with an NSAID, such as Advil (ibuprofen) or Aleve (naproxen). These drugs can help to ease the pain of menstrual cramps, but they may provoke bleeding.

When a hormonal imbalance is a problem, bleeding can be controlled with progesterone or a combination of progesterone and estrogen, often in the form of an oral contraceptive.

If you are diagnosed with fibroids, you might need hormone therapy or a procedure to remove them. Endometrial ablation, once commonly used to treat excessive bleeding in people past childbearing age who wanted to avoid hysterectomy, has now been replaced by a therapy called thermal balloon ablation.

In most cases, thermal balloon ablation ends bleeding by destroying the lining of the uterus. Therefore, it's only appropriate for people who are through having children or are certain they don't want them.

However, this procedure does not guarantee 100% protection from pregnancy. People who do not desire children should continue using their preferred birth control method after having a thermal balloon ablation.

Frequently Asked Questions (FAQs)

Is obesity a risk factor for abnormal uterine bleeding?

Obesity is associated with PCOS, one of the causes of abnormal uterine bleeding.

How long can you continue to take progesterone for abnormal uterine bleeding?

Your healthcare provider may prescribe hormone therapy for you to help manage abnormal uterine bleeding. You might only need to use progesterone treatment for a few months, but you might continue to take it for years if it helps control your symptoms.

How is abnormal uterine bleeding treated?

The treatment for abnormal uterine bleeding depends on the cause. You might need hormone therapy, a procedure, or treatment for an infection or a bleeding disorder.

How is abnormal uterine bleeding diagnosed?

There are different ways to identify the cause of abnormal menstrual bleeding, including a pelvic exam, blood tests, imaging tests, and biopsy, if necessary,

When should you worry about abnormal bleeding?

During pregnancy, you should see your healthcare provider urgently if you experience vaginal bleeding. Otherwise, see your healthcare provider if you need to change your pad or tampon more than every hour during your period, if you are bleeding excessively for more than 24 hours, or if you feel lightheaded or dizzy. If your period lasts for longer than seven days or if you have bleeding between your periods, talk to your healthcare provider.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Tracee Cornforth
Tracee Cornforth is a freelance writer who covers menstruation, menstrual disorders, and other women's health issues.