A period that lasts longer than 7 days is abnormal uterine bleeding, and it usually has a findable cause. MedlinePlus says the most common reason is a hormone imbalance in which the ovary does not release an egg, but growths in the womb (fibroids, polyps, adenomyosis), thyroid disease, PCOS, bleeding disorders, a copper IUD, perimenopause and, rarely, cancer can all keep a period going. Bleeding through two or more pads an hour for two to three hours is an emergency.
What counts as a period that is not stopping?
A period that lasts more than 7 days counts as abnormal. MedlinePlus says periods usually last about 4 to 7 days and come every 24 to 34 days. The NHS and Cleveland Clinic both use 7 days as the cut-off for heavy menstrual bleeding (menorrhagia). Cleveland Clinic adds that it is also abnormal to pass clots about the size of a quarter (roughly 2.5 cm) more than once or twice, or to lose more than 5 tablespoons of blood in a period, against a typical 2 to 3.
The NHS lists the practical signs of a heavy period:
- needing to change your pad or tampon every 1 to 2 hours
- using two types of period product together
- bleeding lasting more than 7 days
- passing blood clots larger than about 2.5 cm
- bleeding through to clothes or bedding
- feeling tired or short of breath a lot
Prolonged bleeding is common. Cleveland Clinic says heavy menstrual bleeding affects about 27% to 54% of people who menstruate. The NHS notes that heavy periods can be normal for some women and often happen when periods first start, after pregnancy or approaching menopause. What matters is a change from your own pattern, bleeding that affects daily life, or bleeding with other symptoms. The ten causes below are the ones the NHS, Cleveland Clinic and MedlinePlus list, grouped by where the problem sits.
Which growths in the womb cause prolonged bleeding?
Fibroids, endometrial polyps and adenomyosis are the three structural causes that gynaecologists look for first. All three are non-cancerous, and all three are found on an ultrasound scan.
1. Fibroids. The NHS says fibroids are "common, non-cancerous growths that develop in or around the womb" and mainly affect women who have not been through the menopause. Many cause no symptoms. When they do, the NHS lists heavy or painful periods, tummy pain, lower back pain, changes in urination, constipation or bloating, pain during sex and difficulty getting pregnant.
2. Endometrial polyps. Cleveland Clinic describes these as growths in the inner lining of the womb that extend into the cavity. Their main symptom is abnormal bleeding: heavy periods, bleeding or spotting between periods, irregular cycles, or bleeding after menopause. You are most likely to develop them in your 40s and 50s; they rarely affect people under 20. Cleveland Clinic says about 1 in 20 can become cancerous.
3. Adenomyosis. The NHS says adenomyosis is "where the lining of the womb starts growing into the muscle in the wall of the womb". It causes severe painful periods, heavy bleeding, pelvic pain, bloating and pain during or after sex. Symptoms usually affect women over 35. The NHS warns that "it can take a long time to diagnose adenomyosis", and that an ultrasound or MRI is used to tell it apart from endometriosis and fibroids.
Which hormone problems keep a period going?
A hormone imbalance is the single most common reason a period runs long. MedlinePlus says abnormal uterine bleeding is "most often" caused by a hormone imbalance, such as when the ovaries do not release an egg. Four conditions do this.
4. Anovulation at the start and end of reproductive life. The NHS says heavy periods can happen when you first start your periods and when approaching menopause. MedlinePlus says newly menstruating girls may have periods 21 to 45 or more days apart.
5. Perimenopause. The NHS says one of the first signs of perimenopause is a change to periods: they may happen more or less often, become irregular, and "may get heavier or lighter". The NHS tells women to contact a GP if they are "bleeding more, not less, than before".
6. Thyroid disease. Cleveland Clinic lists thyroid disease among the hormonal causes of heavy bleeding, and MedlinePlus includes thyroid function among the blood tests for abnormal bleeding. An underactive thyroid also causes tiredness, feeling cold, weight gain, constipation and dry skin. A thyroid test is a routine part of the work-up.
7. PCOS. The NHS, Cleveland Clinic and MedlinePlus all list polycystic ovary syndrome as a cause. In PCOS, ovulation is irregular or absent, so periods come after long gaps and can then be very heavy and prolonged. Acne, excess facial hair, weight gain and dark skin patches on the neck point towards it.
Can medicines, devices, pregnancy or a blood disorder be the cause?
Yes. Three more groups of causes come from outside the womb's own tissue.
8. Contraception and medicines. The NHS says that after an IUD (copper coil) is fitted, "your periods may become heavier, longer or more painful" and that this "may improve after a few months". Cleveland Clinic also lists hormonal IUDs, implants, some pills and injectables, blood thinners, aspirin, hormone replacement therapy and tamoxifen, and notes that forgetting to remove a device when it is due can cause bleeding.
9. Bleeding disorders. The NHS says von Willebrand disease is "an inherited condition where your blood does not clot properly, so you bleed more easily", and lists heavy periods alongside easy bruising, nosebleeds and bleeding gums as its common symptoms. Cleveland Clinic adds liver or kidney disease, leukaemia and platelet disorders.
10. Pregnancy complications and cancer. MedlinePlus says abnormal uterine bleeding by definition does not occur during pregnancy; bleeding in pregnancy has its own causes. Cleveland Clinic lists miscarriage and ectopic pregnancy among them. The NHS says ectopic pregnancy symptoms start between the 4th and 12th week and include tummy pain low down on one side, vaginal bleeding or brown watery discharge, and pain in the tip of the shoulder. Cancer is rare but real: the NHS says "rarely, heavy periods can be a sign of womb cancer", and lists heavy periods that are unusual for you, bleeding between periods and bleeding after menopause as its symptoms. Cleveland Clinic adds endometrial hyperplasia (a precancerous thickening), cervical cancer, and infections such as chlamydia and gonorrhoea.
How do I tell which cause is likely?
The pattern of bleeding and the symptoms around it point towards a cause, though only tests confirm it. This table matches each cause with the clue the sources give.
| Cause | Typical clue | Source |
|---|---|---|
| Fibroids | Heavy or painful periods plus pelvic pressure, frequent urination, constipation, lower back pain; under 50 | NHS |
| Endometrial polyps | Spotting between periods, irregular cycles; age 40 to 59 | Cleveland Clinic |
| Adenomyosis | Severe period pain that stops daily activities, bloating, pain after sex; over 35 | NHS |
| Anovulation (teens, perimenopause) | Cycles that change timing every month, long gaps then a heavy bleed | MedlinePlus, NHS |
| Perimenopause | Periods closer together or further apart, heavier or lighter, in the 40s | NHS |
| Thyroid disease | Tiredness, feeling cold, weight gain, constipation, dry skin | MedlinePlus, Cleveland Clinic |
| PCOS | Long gaps between periods, acne, facial hair, weight gain, dark neck patches | NHS, Cleveland Clinic |
| Copper IUD | Heavier, longer periods in the months after fitting | NHS |
| Bleeding disorder | Easy bruising, nosebleeds, bleeding gums, heavy periods since the first period | NHS |
| Pregnancy complication | Missed period, positive test, one-sided pain, shoulder-tip pain | NHS |
| Womb or cervical cancer | Bleeding after menopause, between periods or after sex, change in discharge | NHS |
Two clues cut across the table. Bleeding between periods or after sex is a reason to see a GP in its own right, according to the NHS. And the NHS says feeling tired or short of breath a lot is itself a sign that bleeding is heavy enough to matter, because it suggests anaemia.
When is prolonged bleeding an emergency?
Bleeding through two or more pads or tampons every hour for two to three hours in a row is an emergency. That is the threshold Cleveland Clinic gives for seeking emergency care; MedlinePlus describes the same level as heavy bleeding that needs a provider.
Go to an emergency department, or call 112 in India, the same day if you are soaking two or more pads an hour for two to three hours, if you feel faint, dizzy or very short of breath, if you have a sharp sudden pain low in the tummy with a missed period or positive pregnancy test, or if you are pale and your heart is racing. The NHS says these last signs can mean a ruptured ectopic pregnancy.
Short of an emergency, the NHS says to see a GP if heavy periods are affecting your life, have gone on for some time, come with severe pain, or if you bleed between periods or after sex.
The anaemia risk is higher in India than in most countries. A 2024 analysis of NFHS-4 and NFHS-5 data in BMC Public Health reported that 57% of Indian women aged 15 to 49 were anaemic in 2019 to 2021, up from 53% in 2015 to 2016, using the WHO cut-off of haemoglobin below 12 g/dL for non-pregnant women. The NHS says heavy periods are a very common cause of iron deficiency anaemia. A woman who starts a long period already anaemic has little reserve, which is why the first test is a blood count.
Which tests will the gynaecologist order?
A blood count and a pelvic ultrasound are the two core tests; everything else depends on what they show. MedlinePlus lists the blood tests used for abnormal uterine bleeding: a blood count, a clotting profile, liver function, blood sugar or HbA1c, hormone levels, a pregnancy test and thyroid function. Cleveland Clinic says blood tests check for anaemia, clotting problems and thyroid disease, and that pelvic ultrasound is "the most common diagnostic test".
In order, a gynaecologist usually arranges:
- A complete blood count to measure haemoglobin and platelets.
- A urine or blood pregnancy test.
- A thyroid function test.
- A pelvic ultrasound, done through the abdomen or transvaginally. The NHS says the scan shows whether fibroids are present, how many, where and how big; Cleveland Clinic calls transvaginal ultrasound the go-to test for polyps.
- A clotting screen if bleeding has been heavy since the first period or there is a history of bruising or nosebleeds. The NHS says von Willebrand disease needs several blood tests over days or weeks and a referral to a haematologist.
If the ultrasound shows a growth or the lining looks thick, the next steps are a sonohysterogram (ultrasound with sterile fluid in the womb), a hysteroscopy (a thin lighted tube through the cervix, which can also remove a polyp), or an endometrial biopsy to check the lining for hyperplasia or cancer. The NHS says adenomyosis may need an MRI.
How is a period that will not stop treated?
Treatment depends on the cause, and the NHS says heavy periods do not always need treating. When they do, the NHS and Cleveland Clinic list the same ladder.
Medicines first. The NHS lists tranexamic acid to reduce bleeding, prescription anti-inflammatory painkillers such as mefenamic acid or naproxen, and hormonal contraception: the intrauterine system (hormonal coil) or the combined pill. MedlinePlus adds low-dose birth control pills, a progestin-releasing IUD, NSAIDs taken before the period, high-dose oestrogen for very heavy bleeding, and iron supplements for anaemia. For von Willebrand disease the NHS adds desmopressin. Cleveland Clinic adds GnRH agonists and antagonists for fibroids.
Procedures if medicines fail. The NHS lists endometrial ablation (removing the womb lining with heat), removal of fibroids (myomectomy), uterine artery embolisation (blocking the blood supply to fibroids so they shrink), and hysterectomy. Cleveland Clinic adds hysteroscopic polyp removal and dilation and curettage. Polyps are usually removed because, as Cleveland Clinic says, removal is the main treatment when they cause symptoms. For adenomyosis the NHS says hysterectomy is the only cure but ends fertility.
Iron. The NHS treats iron deficiency with iron tablets for about six months, taken with or after food, and suggests orange juice afterwards to help absorption. Tea, coffee and dairy reduce absorption.
In India, government hospitals and Ayushman Bharat-empanelled hospitals carry out ultrasound, hysteroscopy and fibroid surgery; ask about the scheme before paying privately. This guide is general information from the sources listed below, not medical advice; a registered doctor makes decisions with you.
