6 Common Causes of Heavy Periods
Understanding Heavy Periods
Many women grow up assuming their periods are “normal”—even when they’re not. Bleeding through your clothes, passing large clots, feeling dizzy or short of breath, or needing to change a tampon every hour are all signs your period may be too heavy.
In fact, about 10% of women experience clinically heavy bleeding, yet most never get evaluated. Heavy periods can have many causes, some minor and others more serious, but all deserve attention and proper diagnosis.
Here are six of the most common reasons behind heavy menstrual bleeding.
1. Uterine Polyps
Uterine polyps are small, typically benign growths that form inside the lining of the uterus (the endometrium). These growths can cause irregular or heavy bleeding and spotting between cycles.
Because polyps form inside the uterus, they aren’t visible during a routine pelvic exam or Pap smear. They’re usually diagnosed with a vaginal ultrasound or a special type of ultrasound that uses saline to visualize the uterine cavity. The good news: polyps can often be removed easily through a hysteroscopy, a minimally invasive procedure using a small camera inside the uterus.
2. Uterine Fibroids
Fibroids are noncancerous growths made up of muscle tissue from the uterus (the myometrium). They’re incredibly common—up to 70% of women will have them at some point—and they can cause painful, heavy periods and even anemia.
Depending on their size and location, fibroids can also cause cramping, bloating, or an enlarged uterus. Some medications can help manage symptoms, but surgery may be necessary in more severe cases. For women trying to conceive, fibroids that affect the uterine cavity may need to be removed to improve fertility.
3. Adenomyosis
Adenomyosis is an inflammatory condition where endometrial tissue grows into the muscular wall of the uterus. It’s often linked to prior pregnancies or uterine procedures and can cause heavy, painful periods.
On exam, the uterus may feel soft or enlarged, and diagnosis typically requires an ultrasound or MRI. While surgery isn’t recommended for most patients with adenomyosis, hormonal treatments can help control bleeding. For those trying to conceive, IVF may be necessary after suppressing the condition with medication.
4. Endometrial Cancer
While less common, heavy bleeding can also be an early warning sign of cancer within the uterus. Endometrial cancer is more likely to occur in women who aren’t ovulating regularly. Without ovulation, estrogen continuously stimulates the uterine lining to grow without the balancing effect of progesterone, increasing cancer risk.
This is why it’s essential to take irregular or absent periods seriously. Diagnosis requires an endometrial biopsy, a simple office procedure that samples cells from the uterine lining.
5. Anovulation
Sometimes, the cause of heavy bleeding isn’t structural but hormonal. Anovulation—when the ovaries don’t release an egg—disrupts the hormonal balance that controls the menstrual cycle. Without regular ovulation, the uterine lining keeps thickening until it sheds unpredictably, leading to prolonged or heavy bleeding.
Anovulation can occur due to stress, thyroid disorders, polycystic ovary syndrome (PCOS), or other hormonal imbalances. Treatment depends on the cause but may include hormone therapy or addressing underlying medical issues.
6. Retained Products of Conception
If you’ve had a recent pregnancy or miscarriage, heavy bleeding could signal that a small piece of placenta or pregnancy tissue remains inside the uterus. This retained tissue can cause inflammation and abnormal bleeding.
If you experience a change in your bleeding pattern after pregnancy, it’s essential to get checked. An ultrasound can confirm if tissue remains and guide treatment.
When to Seek Help
If your period suddenly changes—becomes heavier, more painful, or unpredictable—it’s worth an evaluation. Sometimes, underlying conditions like thyroid disease or hormonal imbalance may be at play.
Heavy bleeding isn’t something to “just live with.” Whether it’s medical or surgical, there are treatments that can help.
