Fibroids and Bleeding Between Periods: What You Need to Know


During their reproductive years, women experience a monthly menstrual cycle. The menstrual cycle is approximately 28 days long, made up of four stages: Menstruation, the follicular phase, ovulation, and the luteal phase. 

Menstruation (your period) lasts from approximately day one to seven of your cycle (as long as pregnancy doesn’t occur.) During this time, the uterine lining and unfertilized egg shed through the vagina, which causes vaginal bleeding. The bleeding is typically quite heavy, often requiring some form of menstrual hygiene product, like pads or tampons. Some women also choose to wear period underwear during this time to safeguard against leaks.

Every woman’s cycle is different and rarely runs like clockwork. Fluctuations in cycle length and period flow is normal and to be expected. So, what’s not normal?

Heavy uterine bleeding in between periods is not considered normal and may require a visit to the doctor. When we say ‘heavy,’ we’re talking about more than just spotting. Heavy bleeding refers to bleeding that requires the use of a pad or tampon. 

Many things might cause heavy uterine bleeding between periods (and heavy menstrual bleeding too), including uterine fibroids. This article dives into what you need to know about fibroids, including:

  • What they are
  • Causes 
  • Risk factors
  • Symptoms 
  • Diagnosis
  • Treatments 

What Are Fibroids?

The Mayo Clinic describes uterine fibroids as ‘non-cancerous growths of the uterus that often appear during childbearing years’. These benign tumours are known to cause irregular periods and/or heavy bleeding between periods. 

In terms of size, they can be as small as a pea or as large as a grapefruit! Fibroids can happen anywhere in or around the uterus and are only an issue if they grow large enough to put pressure on your reproductive organs and get in the way of their normal functioning.

Fibroids are very common and often nothing to worry about—around 20%-50% of women will have them at one point or another during their reproductive years, according to John Hopkins. Fibroids are non-cancerous most (99%) of the time. But, in the case of the other 1%, there are treatments available to help.

Types of Fibroids

Fibroids are all the same, but they can be categorized based on their location. There are three main places fibroids tend to grow.

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Within the uterine wall

Intramural fibroids

Inside of the uterine wall, projecting into its cavity

Submucosal fibroids 

Outside of the uterus

Subserosal fibroids

What Causes Uterine Fibroids is Relatively Unknown

We don’t know too much about what causes uterine fibroids. But, based on many clinical tests, it’s likely fibroids are closely related to:

Risk Factors

Though the exact cause of uterine fibroids is still unclear, the medical world has a pretty good understanding of the risk factors that make someone more likely to develop them.

You’re more likely to develop fibroids if you:

  • Are a female of reproductive age
  • Are of African-American heritage
  • Are overweight
  • Eat a diet high in red meats
  • Don’t consume a lot of green vegetables, dairy, and fruits
  • Have a high alcohol intake


As mentioned, most women who have fibroids aren’t even aware of it. According to Harvard Health, approximately 25%-35% of women aged 35-50 experience symptoms due to fibroids. In rare cases, symptoms can be so severe that treatment–or even surgery–is needed.

The severity of symptoms depends on the number, size, and location of the fibroids. The most common sign of fibroids is heavy periods and  bleeding between periods. If you experience that along with any of the following symptoms, it’s a good indication you have uterine fibroids, and you should visit your doctor to discuss whether medical treatment is needed

  • Very long and heavy menstrual periods (more than seven days)
  • Pelvic pain
  • Pain in the back or lower legs
  • Pain during sex
  • Trouble peeing or pooping (this is a sign the fibroid is putting pressure on your bowels)
  • Frequent urination

Pregnancy and Fibroids

Fibroids generally won’t prevent you from getting pregnant. However, submucosal fibroids can sometimes cause pregnancy loss or infertility. 

According to The Mayo Clinic, uterine fibroids may also increase your chances of complications during pregnancy, like placental abruption (when the placenta detaches from the uterus) and fetal growth restriction (when an unborn baby remains smaller than average for a long portion of the pregnancy), or premature delivery.

If you want to get pregnant and have uterine fibroids, or are at high risk of developing them, speak to your doctor to explore your options.

Diagnosis & Tests of Fibroids

If you experience any of the symptoms mentioned above, you should see your doctor immediately to get tested for fibroids. Most uterine fibroids are detected during routine pelvic exams. Your medical doctor will usually feel the mass while she examines you. Depending on what she detects, she may order more tests to examine the fibroid more closely.

Some common tests for uterine fibroids include:

  • X-ray
  • Ultrasound 
  • MRI
  • Blood test (to check for anemia due to extra blood loss between periods).
  • Hysterosalpingography (this is an x-ray exam of the uterus and fallopian tubes that uses a special dye).
  • Hysteroscopy (a doctor inserts a thin instrument up your vagina to visually examine the cervix and uterus).
  • Endometrial biopsy (the doctor will remove a sample of the fibroid tissue to examine it more closely).

Treatment of Fibroids

Most uterine fibroids shrink over time on their own, especially as women approach menopause and levels of estrogen drop. So, if your doctor detects fibroids, she will most likely recommend a ‘wait and see’ approach. If you experience some minor pelvic pain, she might prescribe some anti-inflammatory painkillers.

If your symptoms are more severe, your doctor may recommend surgery and/or treatment  for your fibroid(s). Your doctor will make the judgement call based on a variety of factors like the size of the fibroids, whether or not they are causing you a lot of pain, your age if you’re planning on getting pregnant, and your past health history.

As a last resort, your doctor may recommend one or more of the following, more intense treatments, as outline by John Hopkins Medicine:

  • Medical menopause (a therapy that reduces your levels of estrogen, essentially inducing menopause).
  • Anti-hormonal medicines (some medicines seem to oppose estrogen and have been used to treat fibroids).
  • Minor surgery (fibroids are removed, but the uterus is left intact).
  • Fibroid embolization (a newer technique that blocks off the arteries supplying blood to the fibroids. Cutting off blood supply will shrink them). 
  • Hysterectomy (complete removal of the uterus. They will only do this in the most extreme cases).

Other Causes of Bleeding Between Periods

If you’re experiencing heavy bleeding between periods, it may be caused by something other than uterine fibroids. There are a host of other reasons why you may experience irregular bleeding, including:

  • Birth Control Pill: Also known as breakthrough bleeding, it often occurs in the first six months of taking a new birth control pill, according to Medical News Today.
  • Morning-After Pill: According to the Mayo Clinic, the morning-after pill may cause bleeding between periods or heavier menstrual bleeding.
  • Intrauterine Device (IUD): Some women with an IUD for birth control may also experience bleeding outside the menstrual phase.
  • Medications: Certain medications may cause abnormal vaginal bleeding. Your pharmacist should advise you if this is the case.
  • Infections: sexually transmitted infections (STI) or pelvic inflammatory disease (PID) can also cause vaginal bleeding between periods.
  • Ectopic pregnancy or miscarriage: Irregular vaginal bleeding is a symptom of both ectopic pregnancy and a miscarriage.
  • Ovarian cysts: Ovarian cysts are fluid-filled sacs in or on the ovaries that can cause you to bleed between periods and lead to conditions like polycystic ovarian syndrome (PCOS).
  • Blood clotting disorders: For example, von Willebrand disease.
  • Cancer: Cancer or pre-cancer of the reproductive organs may also cause abnormal bleeding.
  • Perimenopause & Menopause: A drastic change in hormone levels causes women to experience irregular periods or skipped periods.

    In Summary

    Uterine fibroids are often nothing to be concerned about and very common. If you experience symptoms caused by fibroids, you can talk to your doctor about treatment. However, unless the symptoms are very severe and reduce your quality of life or if you’re trying to get pregnant, it’s unlikely medical treatment will be required.

    Having said that, if you notice heavy bleeding between periods, irregular periods, abdominal pain and cramping, or unusual vaginal discharge, you should visit your doctor as soon as possible as something other than fibroids could be the culprit.