Uterine bleeding is any bleeding that originates from the uterus, including normal monthly periods and any bleeding that falls outside typical patterns. A normal menstrual cycle occurs every 21 to 35 days, lasts 2 to 7 days, and follows a relatively predictable rhythm. When bleeding is heavier, longer, more frequent, or occurs at unexpected times, it’s considered abnormal uterine bleeding, a condition that up to 30% of women experience at some point in their lives.
How Normal Menstrual Bleeding Works
Each month, your uterine lining thickens in response to hormones, preparing for a possible pregnancy. If pregnancy doesn’t occur, progesterone levels drop sharply. That drop is the direct trigger for menstruation. Once progesterone withdraws, the blood vessels supplying the lining constrict, cutting off blood flow to the upper layers of tissue. The tissue breaks down, and your body sheds it along with blood over the course of your period.
This process involves a carefully orchestrated sequence. After progesterone falls, immune cells flood the lining and enzymes begin dissolving the tissue’s structural framework. At the same time, the constriction of the spiral arteries in the uterine wall helps limit how much blood is lost. When this system works properly, bleeding stays within a predictable range. When any part of the process misfires, whether it’s the hormonal signals, the blood vessel response, or the tissue breakdown itself, bleeding can become abnormal.
What Counts as Abnormal
Abnormal uterine bleeding (AUB) is a broad term covering any pattern that deviates from a typical cycle. It can mean periods that are too heavy, too long, too frequent, irregular, or bleeding that happens between periods or after menopause. Specific signs of heavy bleeding include:
- Soaking through one or more pads or tampons every hour for several consecutive hours
- Needing to double up on pads to control flow
- Having to change pads or tampons overnight
- Passing blood clots the size of a quarter or larger
- Bleeding that lasts longer than 7 days
If any of these apply to you, your bleeding likely warrants evaluation. Many women normalize heavy periods because they’ve never known anything different, but consistently soaking through protection that quickly is not a variation of normal.
Common Causes
Doctors categorize the causes of abnormal uterine bleeding into two groups: structural problems you can see on imaging and non-structural problems related to hormones, clotting, or other systemic issues.
Structural Causes
These involve physical changes in the uterus itself. Polyps are small growths on the uterine lining that can cause irregular or heavy bleeding. Adenomyosis occurs when the tissue that normally lines the uterus grows into the muscular wall, often causing painful, heavy periods. Fibroids (noncancerous muscle tumors) are extremely common and can distort the uterine cavity, leading to prolonged or heavy flow. In rarer cases, precancerous changes or cancer of the uterine lining can be the source.
Non-Structural Causes
Ovulatory disorders are among the most frequent non-structural causes. When ovulation doesn’t happen regularly, as in polycystic ovary syndrome or during perimenopause, the hormonal signals that control the buildup and shedding of the lining become erratic. This can lead to prolonged stretches without a period followed by very heavy bleeding. Clotting disorders, particularly inherited conditions like von Willebrand disease, can make periods significantly heavier because the body struggles to stop bleeding normally. Certain medications, including blood thinners and some forms of hormonal contraception, can also cause unexpected uterine bleeding.
The Iron Deficiency Connection
Heavy uterine bleeding and iron deficiency are tightly linked, and this connection is underrecognized. A study published through the American Society of Hematology found that among adolescents who came to the emergency department with heavy menstrual bleeding, over 90% were iron deficient. Nearly 80% had iron deficiency with anemia. Symptoms like fatigue, brain fog, dizziness, and shortness of breath during exertion often get chalked up to stress or poor sleep when iron depletion is the real cause. If your periods are consistently heavy, your iron stores are very likely affected even if you haven’t been formally diagnosed with anemia.
How Abnormal Bleeding Is Evaluated
Evaluation typically starts with a detailed history of your bleeding patterns and a physical exam. Blood work checks for anemia, thyroid problems, and sometimes clotting disorders. From there, the next step depends on your age, risk factors, and symptoms.
Transvaginal ultrasound is the most common first-line imaging tool. It gives a clear picture of the uterine wall and can identify fibroids, polyps, or unusual thickening of the lining. If the ultrasound suggests something but can’t provide a definitive answer, a procedure called sonohysterography (where fluid is placed in the uterus during ultrasound) or hysteroscopy (where a small camera looks inside the uterus) can offer more detail.
For women at increased risk of precancerous or cancerous changes, particularly those over 45, those with obesity, or those with prolonged irregular cycles, an endometrial biopsy is often recommended. This involves taking a small sample of the uterine lining, usually done in a clinic visit. MRI is reserved for cases where other imaging is inconclusive or not feasible.
Postmenopausal Bleeding
Any bleeding that occurs after menopause, defined as 12 consecutive months without a period, requires prompt evaluation. While most causes turn out to be benign, roughly 9% of postmenopausal women who see a doctor for bleeding are eventually diagnosed with endometrial cancer, according to data compiled by the National Cancer Institute. That rate varies by region, ranging from about 5% in North America to 13% in Western Europe. The 91% who don’t have cancer typically have bleeding caused by thinning of the vaginal or uterine lining, polyps, or hormone-related changes. Regardless of the likely cause, postmenopausal bleeding always justifies investigation.
Treatment Options
Treatment depends entirely on the cause, your age, and whether you want to preserve fertility. For many women, medical management is the first approach.
Medication-Based Approaches
Hormonal treatments are considered first-line for most cases of abnormal uterine bleeding. A hormonal intrauterine device that releases a small amount of progestin locally into the uterus is one of the most effective long-term options, dramatically reducing menstrual flow for most users. Oral contraceptives, taken on a monthly or extended cycle, regulate the hormonal signals that control lining buildup and shedding. Oral progestin therapy works similarly for women who aren’t candidates for estrogen-containing options.
For women who prefer non-hormonal treatment, tranexamic acid helps the blood clot more effectively in the uterus and has been shown to reduce bleeding by 30 to 55%. It’s taken only during the days of heaviest flow. Anti-inflammatory medications can also reduce menstrual blood loss by altering the balance of compounds that control blood vessel behavior in the uterine lining.
Procedural Options
When medications aren’t enough or a structural cause needs to be addressed, several procedures are available. Endometrial ablation destroys the uterine lining using heat, cold, or other energy sources. It’s effective for reducing bleeding, but it’s not a permanent solution for everyone. Studies show that 19 to 21% of patients who had ablation in the setting of fibroids, adenomyosis, or polyps eventually needed a hysterectomy. It’s also not appropriate for women who want future pregnancies.
For fibroids specifically, uterine fibroid embolization is a minimally invasive procedure that blocks blood flow to fibroids, causing them to shrink. It has a success rate above 90% for eliminating fibroid-related symptoms and offers a shorter recovery than surgery. Hysterectomy, the removal of the uterus, remains the only definitive cure for uterine bleeding and is typically reserved for cases where other treatments have failed or when cancer is present.
What Heavy Bleeding Feels Like Day to Day
The practical burden of abnormal uterine bleeding goes well beyond what happens in a bathroom. Women with heavy periods often plan their lives around their cycles, avoiding travel, exercise, social events, and even certain clothing during their worst days. The combination of blood loss and iron depletion creates a cycle of exhaustion that can persist even between periods. Sleep is disrupted by overnight pad changes. Work productivity drops. Many women describe a sense of dread as their period approaches, knowing what’s coming.
If this sounds familiar, it’s worth knowing that effective treatments exist and that tolerating heavy bleeding as “just how it is” comes with real health consequences, iron deficiency being the most measurable. Tracking your cycle, the number of products you use per day, and any clots you pass gives your doctor concrete information to work with and moves the conversation toward solutions faster.