Introduction
Abnormal uterine bleeding (AUB) means bleeding from the uterus that differs from a person’s usual menstrual pattern—too heavy, too long, too frequent, too infrequent, or bleeding between periods or after sex. Most people menstruate from about ages 11–12 until around menopause near age 50; over that span, occasional irregular cycles can happen, but persistent change deserves evaluation.
A typical cycle often comes every 21–35 days, lasts up to about 7–8 days, and is not dominated by large clots or disabling pain. Estrogen and progesterone shape the uterine lining (endometrium); when the lining sheds, menstrual bleeding occurs. Cycles shorter than 21 days or longer than 35 days, or bleeding that is markedly heavier or longer than usual, are considered abnormal for many people.
AUB can include bleeding between periods, spotting through the cycle, bleeding after intercourse, very heavy periods with clots, prolonged bleeding, or missing periods for three usual cycle lengths or about six months. Irregularity is more common in the first years after menarche and again as menopause approaches, but heavier bleeding still needs checking.
Causes range from hormonal imbalance and contraceptive effects to pregnancy-related problems, fibroids or polyps, thyroid disease, bleeding disorders, and—less often—cancer. This page is general education: a gynecologist’s assessment is needed to find the cause and choose safe treatment, especially if pregnancy is possible or bleeding is severe.
Overview
AUB is a pattern of uterine bleeding outside what is normal for that person’s age and cycle history—not a single disease. Severity and cause vary widely, so the same symptom can need very different care.
Keeping a menstrual calendar for 4–6 months (dates, flow, clots, pain, spotting) helps clinicians see patterns that a single visit may miss.
Treatment is guided by cause, age, how heavy the bleeding is, anemia risk, and whether future pregnancy is desired. Many people improve with medicines; some need procedures.
- AUB covers heavy, prolonged, irregular, intermenstrual, post-coital, or absent bleeding outside expected norms
- Hormones, pregnancy, contraception, structural lesions (fibroids/polyps), thyroid disease, and rarely malignancy may contribute
- History, exam, pregnancy test, blood work, ultrasound, and sometimes hysteroscopy or sampling clarify the cause
- First-line care often includes non-hormonal medicines that reduce period blood loss and pain
- Hormonal therapy, including progesterone options, may treat imbalance or protect the endometrium
- Surgery (polyp/fibroid removal, ablation, or hysterectomy) is reserved for selected cases after counseling
What happens in the body
In a regular cycle, coordinated estrogen and progesterone growth and shedding of the endometrium produce predictable bleeding. When hormone levels are too high, too low, or poorly timed—or when the uterine cavity has fibroids, polyps, or inflammation—shedding becomes irregular, prolonged, or excessive.
Heavy bleeding can deplete iron stores and cause anemia. Pregnancy-related bleeding (miscarriage, ectopic pregnancy) follows a different pathway and must be ruled out early because it can be urgent.
- Disrupted estrogen–progesterone timing alters endometrial stability
- Structural lesions increase surface area or disrupt cavity lining
- Thyroid or clotting disorders can amplify menstrual blood loss
- Chronic unopposed estrogen can thicken the lining (hyperplasia) and raise cancer risk if untreated
Signs and symptoms
Symptoms of abnormal uterine bleeding vary. The list below covers common possibilities—not everyone has every symptom:
- Periods lasting longer than about 7–8 days
- Cycles shorter than 21 days or longer than 35 days
- Bleeding between periods (intermenstrual bleeding)
- Spotting at unpredictable times in the cycle
- Bleeding after sexual intercourse
- Heavier flow than usual, often soaking pads/tampons more frequently
- Passage of large blood clots
- Cramping or pelvic pain with irregular or heavy flow
- Missed periods for three usual cycles or about six months (when pregnancy is excluded)
- Fatigue, dizziness, or shortness of breath from iron-deficiency anemia
- Pallor or reduced exercise tolerance during heavy months
- Anxiety about unpredictable staining or social/work disruption
- In peri-menopause: shorter cycles that then become much heavier—still warrant review
Causes and risk factors
A clinician makes the diagnosis. Factors commonly considered—more than one may apply—include:
- Hormonal imbalance (excess or insufficient estrogen/progesterone)
- Anovulatory cycles, especially around menarche and perimenopause
- Pregnancy-related causes (including miscarriage or ectopic pregnancy)
- Intrauterine devices or hormonal contraception side effects
- Uterine fibroids or endometrial polyps
- Endometrial hyperplasia or, less commonly, uterine cancer
- Thyroid dysfunction
- Bleeding or clotting disorders; some medicines that affect clotting
- Infection or inflammation of the uterus/cervix
- Polycystic ovary syndrome and other endocrine conditions
Diagnosis and evaluation
Evaluation usually includes history, examination, and tests as needed. Not every patient needs the same panel:
- Detailed menstrual and obstetric history, medicines, and contraceptive use
- Pelvic examination and pregnancy test when appropriate
- Blood tests: complete blood count, iron studies; coagulation tests if indicated
- Thyroid function testing
- Pelvic ultrasound to assess uterus, endometrium, and ovaries
- Menstrual calendar review over several months when available
- Hysteroscopy and/or dilation and curettage (D&C) or endometrial sampling when cavity disease or hyperplasia/cancer must be excluded
- Laparoscopy in selected cases to evaluate other pelvic causes
Treatment and management
Treatment depends on cause, severity, age, anemia, and pregnancy plans. Do not start hormones or strong medicines without clinical advice:
- Non-hormonal medicines taken during periods to reduce pain and blood loss (first-line for many)
- Allow several cycles to judge whether medicines are working
- Hormonal therapy when imbalance or deficiency is suspected; progesterone can treat or prevent endometrial hyperplasia
- Expect that bleeding may be heavier for the first few months on hormones before it lightens
- Iron replacement if anemia or low iron stores are found
- Hysteroscopic removal of polyps or selected fibroids when they drive bleeding
- Endometrial ablation to reduce or stop bleeding permanently in selected people who do not desire future pregnancy (biopsy first; fertility may be impaired)
- Hysterectomy (removal of the uterus) when other options fail or are unsuitable—ends periods and pregnancy capacity
- Treat underlying thyroid, infection, or clotting problems when identified
Prevention, self-care, and lifestyle
Not every condition is fully preventable, but the steps below may lower risk or recurrence:
- Attend recommended gynecologic follow-up if cycles change persistently
- Track periods to catch patterns early
- Discuss contraceptive methods and expected bleeding changes with a clinician before starting
- Manage thyroid disease, PCOS, and obesity when present—these can worsen irregular bleeding
- Avoid unsupervised hormone or herbal “period regulators”
- Seek care promptly for post-menopausal bleeding (any bleeding after menopause needs evaluation)
Possible complications
Delay, missed care, or unsafe self-medication can raise the chance of complications in some cases:
- Iron-deficiency anemia and severe fatigue
- Acute heavy bleeding requiring urgent care or transfusion in rare severe cases
- Endometrial hyperplasia if chronic unopposed estrogen is untreated
- Delayed diagnosis of fibroids, polyps, or malignancy
- Reduced quality of life, work absence, and anxiety about unpredictable bleeding
- Infertility or pregnancy complications related to the underlying cause
- Surgical risks when procedures become necessary after delayed care
When to see a doctor or seek emergency care
Seek prompt medical advice or emergency care if any of the following apply—it is safer not to wait and see:
- Heavy bleeding soaking a pad/tampon hourly, feeling faint, or passing very large clots
- Bleeding with positive pregnancy test, severe pain, or shoulder-tip pain—urgent evaluation
- Bleeding after menopause
- New bleeding after sex, or irregular bleeding lasting more than a few cycles
- Signs of anemia: marked fatigue, dizziness, shortness of breath
- Fever, foul discharge, or severe pelvic pain suggesting infection
- Known clotting disorder or cancer history with new abnormal bleeding
Living with the condition
Most causes of AUB can be managed once identified. Plan rest and iron-rich nutrition during heavy weeks, and keep spare supplies at work or school. Share your menstrual calendar with your clinician so treatment can be adjusted.
If hormones or procedures are recommended, ask how they affect fertility, contraception, and follow-up. Ablation and hysterectomy permanently change fertility options and need clear counseling first.
Persistent irregular bleeding is not something to “wait out” indefinitely—especially with anemia, post-menopausal bleeding, or bleeding after sex. Early assessment usually leads to simpler treatment.
Frequently asked questions
What counts as a normal menstrual cycle?
Many people bleed every 21–35 days for up to about a week without large clots or disabling pain. Cycles outside that range, or a clear change from your own usual pattern, should be reviewed.
Is irregular bleeding always serious?
Not always—some causes are mild and treatable with counseling or medicines. Others, including pregnancy complications or growths, need timely care. Only assessment can tell which applies.
Why keep a menstrual calendar?
Patterns over 4–6 months show frequency, duration, and heaviness better than memory alone and help guide tests and treatment.
Will hormones stop the bleeding immediately?
Often not. It may take a few months; bleeding can be heavier at first before it lightens. Follow-up decides whether the plan is working.
Can I still become pregnant after endometrial ablation?
Ablation is meant to reduce or stop bleeding and can impair fertility. It is not a reliable contraceptive; discuss pregnancy wishes before choosing it.
When is hysterectomy considered?
Usually when medicines and less invasive options fail, are unsuitable, or when disease severity warrants uterus removal after counseling about permanence and recovery.
Important caution
This article is general health education in English. It is not personal medical advice, a prescription, a lab report interpretation, or a promise about hospital costs.
Every patient is different. Decisions about medicines, tests, or surgery should follow evaluation by a qualified clinician.
If bleeding is severe, you may be pregnant, you feel faint, or you have post-menopausal bleeding, seek care without delay.