gynecology
Abnormal Uterine Bleeding: Causes, Evaluation, and Treatment
Abnormal uterine bleeding means bleeding that differs from your normal pattern in timing, volume, duration, or regularity. It is one of the most common reasons people see a gynecologist, and it covers a wide range — from a nuisance to something that needs same-week evaluation.
What counts as abnormal
- Bleeding between periods
- Bleeding after sex
- Cycles shorter than 24 days or longer than 38
- Periods lasting more than 8 days
- Heavy bleeding — soaking a pad or tampon hourly, clots larger than a quarter, waking at night to change
- Cycle length that varies by more than 7–9 days month to month
- Any bleeding after menopause
That last one is categorical. Postmenopausal bleeding is never normal and always needs evaluation, even if it is a single spot. Most causes turn out to be benign — atrophy is the most common — but this is how endometrial cancer presents, and it is highly curable when found early.
The causes, systematically
Clinicians work through a structured list known as PALM-COEIN — structural causes you can see, and non-structural ones you cannot.
Structural (PALM)
- Polyp — usually benign growths of the uterine lining; a common cause of bleeding between periods and after sex.
- Adenomyosis — endometrial tissue within the uterine muscle. Heavy bleeding with severe cramping and a bulky, tender uterus.
- Leiomyoma (fibroids) — very common. Submucosal fibroids, inside the cavity, cause the heaviest bleeding even when small.
- Malignancy and hyperplasia — endometrial hyperplasia and cancer. Risk rises with age, obesity, PCOS, tamoxifen use, and prolonged estrogen unopposed by progesterone.
Non-structural (COEIN)
- Coagulopathy — bleeding disorders, most often von Willebrand disease, which affects roughly 1% of people and is chronically underdiagnosed in women. Suspect it with heavy periods since menarche, easy bruising, frequent nosebleeds, or heavy bleeding after dental work or childbirth.
- Ovulatory dysfunction — the most common cause overall. Without ovulation there is no progesterone to oppose estrogen, so the lining overgrows and sheds unpredictably. Seen in perimenopause, PCOS, thyroid disease, high prolactin, significant weight change, and extreme exercise.
- Endometrial — primary disorders of the lining itself, a diagnosis of exclusion.
- Iatrogenic — medication-related. Anticoagulants, hormonal contraception (especially the first 3–6 months, and with missed pills), the IUD, and tamoxifen.
- Not otherwise classified — including caesarean scar defects and arteriovenous malformations.
Cervical and vaginal causes sit outside this framework and matter for bleeding after sex specifically: cervical polyps, cervicitis, infection including chlamydia, atrophy, and cervical cancer. Bleeding after sex should always prompt a look at the cervix and up-to-date screening.
How it is evaluated
- Pregnancy test first, in anyone who could be pregnant. Bleeding in early pregnancy is a different pathway entirely, and ectopic pregnancy is a medical emergency.
- History — cycle pattern, sexual history, contraception, medications, weight change, bleeding elsewhere.
- Examination — including a speculum exam to see the cervix, since not all bleeding is uterine.
- Blood tests — complete blood count and ferritin, thyroid function, and prolactin where indicated. Clotting studies if a bleeding disorder is suspected — ideally before starting hormonal treatment, which can mask it.
- Cervical screening, if not current.
- Transvaginal ultrasound — endometrial thickness, fibroids, polyps, ovaries.
- Saline infusion sonohysterography — outlines the cavity, revealing lesions a plain scan misses.
- Endometrial biopsy — an office procedure. Indicated over 45, or younger with risk factors, persistent bleeding, or a thickened lining. Any postmenopausal bleeding warrants assessment of the endometrium.
- Hysteroscopy — direct visualisation of the cavity, allowing lesions to be removed in the same procedure.
Treatment
Treatment follows the cause, but the general shape:
Medical
- Tranexamic acid on heavy days — non-hormonal, effective, underused.
- NSAIDs started at the onset of bleeding — reduce flow and pain together.
- Combined hormonal contraception — regulates the cycle and lightens flow.
- Progestogens — cyclical or continuous, supplying the missing signal in ovulatory dysfunction.
- The levonorgestrel IUD — FDA-approved for heavy menstrual bleeding, reduces blood loss by 80–90%, and treats hyperplasia in selected cases.
- Iron replacement — with vitamin C, away from tea and calcium. Intravenous iron if oral is not tolerated or not working.
Procedural
- Hysteroscopic removal of polyps or submucosal fibroids — often curative.
- Endometrial ablation — for those who have completed childbearing.
- Uterine artery embolisation or myomectomy — for fibroids, preserving the uterus.
- Hysterectomy — definitive, and one option among several rather than the default.
Seek care urgently if
- You soak a pad or tampon every hour for two or more hours in a row
- You feel dizzy or faint, or are breathless at rest
- You have severe pelvic pain with fever
- You have any bleeding after menopause
- You are or could be pregnant and are bleeding — particularly with one-sided pain or shoulder-tip pain, which can indicate an ectopic pregnancy
Get it looked at
Abnormal bleeding is common, usually benign, and worth evaluating precisely because the small proportion that is serious is so treatable when found early.
Medical disclaimer
This article is general health information, not medical advice for any individual. Abnormal bleeding needs proper evaluation rather than self-diagnosis. Postmenopausal bleeding, and bleeding in pregnancy, always require prompt medical assessment.