Abnormal Uterine Bleeding (AUB)

Introduction

If you have been told that your bleeding pattern is not normal, or you are being investigated for heavy, prolonged, or irregular periods, you are dealing with what doctors call abnormal uterine bleeding, or AUB. This guide is written for you — someone who already knows there is a problem and is now thinking about the next step: understanding the cause, choosing a treatment, and planning recovery.

AUB is one of the most common reasons women see a gynaecologist at every life stage, from the teenage years through perimenopause and beyond. The encouraging point is that AUB is not a single disease. It is a symptom with many possible causes, and once the cause is identified, there is almost always a way to bring bleeding back under control. Some women need only a short course of medication. Others benefit from a small day-care procedure. A smaller group needs surgery. The path depends on what is causing the bleeding, your age, your overall health, and whether you wish to have children in the future.

This article walks you through what AUB is, why it happens, how it is investigated, and the full range of treatment options that doctors consider — so you can have a more confident conversation with your specialist.

What Is Abnormal Uterine Bleeding (AUB)?

Abnormal uterine bleeding is any menstrual bleeding from the uterus that differs from a typical period in its frequency, regularity, duration, or volume. It also includes bleeding that happens between periods (called intermenstrual bleeding) and any bleeding after menopause.

A typical menstrual cycle in adults occurs roughly every 24 to 38 days, lasts around 4 to 8 days, and involves a manageable volume of bleeding. AUB is diagnosed when one or more of these features are clearly outside the normal range and the pattern is persistent rather than a one-off event.

AUB can present in several recognisable patterns:

• Heavy menstrual bleeding — soaking through pads or tampons quickly, passing large clots, or losing enough blood to cause tiredness and low iron levels (anaemia).
• Prolonged bleeding — periods that last more than 8 days.
• Irregular bleeding — cycles that vary widely in length, or unpredictable spotting.
• Intermenstrual bleeding — bleeding between expected periods.
• Postcoital bleeding — bleeding after sex.
• Postmenopausal bleeding — any bleeding more than 12 months after the last period; this always needs prompt evaluation.

To make sense of the many possible causes of AUB, the International Federation of Gynecology and Obstetrics (FIGO) developed a classification system known as PALM-COEIN. This system is now widely used, including in guidance from the American College of Obstetricians and Gynecologists (ACOG) and the Royal College of Obstetricians and Gynaecologists (RCOG).

The first four causes (PALM) are structural — meaning something can be seen or measured on imaging or under the microscope. The other five (COEIN) are non-structural.

Structural Causes (PALM)

• P — Polyps: small, usually benign growths in the lining of the uterus (endometrium) or cervix that can cause spotting between periods and heavy bleeding.
• A — Adenomyosis: a condition where the lining tissue of the uterus grows into the muscular wall of the uterus, often causing painful and heavy periods.
• L — Leiomyoma (fibroids): non-cancerous muscle growths in the uterine wall. Fibroids that bulge into the uterine cavity (submucosal fibroids) are particularly likely to cause heavy bleeding.
• M — Malignancy and hyperplasia: pre-cancerous thickening of the uterine lining, or cancers of the uterus or cervix. These are uncommon but very important to rule out, especially after age 45 or in postmenopausal bleeding.

Non-structural Causes (COEIN)

• C — Coagulopathy: bleeding disorders such as von Willebrand disease that affect how blood clots. These are an important and sometimes overlooked cause, particularly in teenagers with heavy periods from the start of menstruation.
• O — Ovulatory dysfunction: cycles in which ovulation does not happen regularly. Common in adolescence, perimenopause, polycystic ovary syndrome (PCOS), thyroid disease, and high stress or weight changes.
• E — Endometrial: problems with the local function of the uterine lining itself, even when imaging looks normal.
• I — Iatrogenic: bleeding caused by medical treatment — hormonal contraceptives, intrauterine devices (IUDs), blood thinners, hormone replacement therapy, and some other medications.
• N — Not otherwise classified: rare or poorly understood causes that do not fit elsewhere.

Your doctor will often think about AUB through this framework. It also explains why two women with the same symptom (for example, heavy periods) may need very different treatments — one might have a fibroid, the other a thyroid problem, and the third a bleeding disorder.

Risk Factors

Several factors increase the likelihood of developing AUB or shape what is likely behind it:

• Age and life stage — ovulatory irregularity is common at the start (adolescence) and end (perimenopause) of reproductive life.
• Obesity — affects hormone balance and increases the risk of endometrial hyperplasia.
• Polycystic ovary syndrome (PCOS) — a common cause of irregular and infrequent periods.
• Thyroid disorders — both under- and overactive thyroid can disturb menstrual cycles.
• Diabetes and insulin resistance.
• Use of blood thinners or certain hormonal medications.
• Family history of bleeding disorders, fibroids, or gynaecological cancers.
• Recent pregnancy — bleeding patterns can be disturbed for several months after childbirth or pregnancy loss.

When Bleeding Patterns Should Prompt Evaluation

If you are reading this article you have likely already noticed that something is not right. The patterns that should be reviewed by a gynaecologist include:

• Periods lasting longer than 8 days, especially if this is a change from your usual pattern.
• Soaking through a pad or tampon every 1 to 2 hours for several hours in a row.
• Passing clots larger than a 2-rupee coin (or about the size of a 10p coin).
• Bleeding between periods or after sex.
• Cycles consistently shorter than 24 days or longer than 38 days.
• Any vaginal bleeding after menopause.
• Symptoms of anaemia — tiredness, breathlessness, dizziness, pale skin, or palpitations.
• Severe pain accompanying the bleeding.

Some situations need urgent care rather than a routine appointment: very heavy bleeding causing dizziness or fainting, signs of severe anaemia, pregnancy with bleeding, or bleeding accompanied by fever and pelvic pain. In these situations, contact your doctor or go to an emergency department promptly.

How AUB Is Diagnosed

Because AUB has so many possible causes, evaluation is methodical. The aim is to confirm the bleeding pattern, rule out serious causes (particularly cancer and pre-cancer in older women), and identify what is driving the symptom.

History and Examination

Your gynaecologist will ask detailed questions about your bleeding pattern, your menstrual history, contraception, medications, pregnancies, family history, and general health. Keeping a simple diary or using a period-tracking app for two or three cycles before your appointment is often very helpful. A pelvic examination and a cervical screening test (Pap smear) may be done if appropriate.

Blood Tests

• Complete blood count to check for anaemia.
• Thyroid function tests.
• Pregnancy test in women of reproductive age, as pregnancy-related conditions can present as abnormal bleeding.
• Coagulation tests if a bleeding disorder is suspected, especially in adolescents or women who have had heavy bleeding since their first period.
• Hormonal profile in selected cases (for example, when PCOS or perimenopause is suspected).

Imaging

• Transvaginal ultrasound is usually the first imaging test. It gives a clear view of the uterus and ovaries and can identify fibroids, polyps, adenomyosis, and thickening of the uterine lining.
• Saline infusion sonography (sonohysterography) uses a small amount of fluid placed inside the uterus during ultrasound to outline polyps or submucosal fibroids more clearly.
• MRI is reserved for complex cases, particularly when adenomyosis is suspected or when planning surgery for large or multiple fibroids.

Endometrial Sampling

An endometrial biopsy — taking a small sample of the uterine lining for laboratory examination — is recommended by major societies including ACOG when there is a meaningful risk of pre-cancer or cancer. This typically applies to women over 45 with AUB, younger women with persistent risk factors (such as obesity or chronic anovulation), and any woman with postmenopausal bleeding.

Hysteroscopy

Hysteroscopy is a procedure in which a thin telescope is passed through the cervix to look directly inside the uterine cavity. It is one of the most accurate ways to identify polyps and submucosal fibroids and often allows treatment in the same session (see below).

Treatment and Management

Treatment of AUB is highly individualised. Current guidance from major societies, including ACOG and RCOG, supports starting with the least invasive option that is likely to control the symptom, while taking into account the underlying cause, your age, your preferences, and your reproductive plans.

Medical Treatment

Medication is often the first step for AUB without a clear structural cause, and for many women with fibroids or adenomyosis as well. Options include:

• Levonorgestrel-releasing intrauterine system (hormonal IUD): Major guidelines, including NICE and RCOG, describe this as a leading first-line option for heavy menstrual bleeding when contraception is also acceptable. It reduces bleeding significantly in most users over time.
• Combined hormonal contraceptives (pills, patches, or rings): help regulate cycles and reduce bleeding volume in suitable candidates.
• Progestogen-only therapy: oral progestogens or injectable forms can be used to control bleeding, particularly when oestrogen-containing options are not appropriate.
• Tranexamic acid: a non-hormonal medication taken during periods to reduce bleeding volume. It does not affect the cycle itself or fertility.
• Non-steroidal anti-inflammatory drugs (NSAIDs) such as mefenamic acid: reduce bleeding modestly and help with cramping.
• GnRH analogues: medications that temporarily suppress ovarian function, often used short-term before fibroid surgery to shrink fibroids and improve anaemia.
• Treatment of underlying conditions: thyroid medication, treatment of bleeding disorders, weight management for PCOS-related bleeding, or stopping a medication that is contributing to the problem.
• Iron supplementation: not a treatment for the bleeding itself, but very important if blood tests show iron deficiency or anaemia.

Minimally Invasive Procedures

When a structural cause is found, or when medication does not control symptoms, several uterus-preserving procedures are available.

• Hysteroscopic polypectomy: removal of endometrial polyps through a hysteroscope, usually as a day-care procedure.
• Hysteroscopic myomectomy: removal of submucosal fibroids (those bulging into the cavity) through a hysteroscope, without any external cuts.
• Endometrial ablation: a procedure that destroys the lining of the uterus using heat, cold, radiofrequency, or other energy sources. It significantly reduces or stops menstrual bleeding in many women. Ablation is offered to women who have completed their family, because pregnancy after ablation is unsafe and not advised.
• Uterine artery embolisation: a procedure performed by an interventional radiologist in which the blood supply to fibroids is blocked, causing them to shrink. It can preserve the uterus but may affect future fertility and is generally not the first choice for women planning pregnancy.
• Laparoscopic myomectomy: keyhole surgical removal of fibroids that are in the wall of the uterus or on its outer surface, preserving the uterus for future pregnancy.

Hysterectomy

Hysterectomy, the surgical removal of the uterus, is a definitive treatment for AUB that has not responded to other options or where the cause is serious (such as cancer or large symptomatic fibroids in a woman who has completed her family). It is generally considered after other approaches have been explored, except in specific circumstances such as malignancy. Hysterectomy can be performed through the vagina, by keyhole (laparoscopic or robotic) surgery, or as an open operation, depending on the underlying condition, uterine size, and surgical considerations. Hysterectomy ends both menstruation and the possibility of future pregnancy.

How Doctors Choose Between Options

The choice between medical treatment, a minimally invasive procedure, and surgery is shaped by:

• The underlying cause identified during evaluation.
• Whether you wish to have children in the future.
• The severity of bleeding and its effect on daily life.
• Other medical conditions and current medications.
• Your age and proximity to menopause.
• Your own preferences after the options have been explained.

Major societies emphasise that the patient’s informed preference is a central part of the decision, particularly when more than one option is medically reasonable.

Fertility and Future Pregnancy

If you wish to have children in the future, this should be discussed openly with your gynaecologist before any treatment is started, because some options preserve fertility and others do not.

• Fertility-preserving options: most medical treatments (once stopped), hysteroscopic removal of polyps and submucosal fibroids, and laparoscopic myomectomy. Treating underlying causes such as thyroid disease or PCOS can actually improve fertility.
• Options that end fertility: endometrial ablation and hysterectomy. These should not be chosen if future pregnancy is desired.
• Options with mixed effects: hormonal contraceptives and the hormonal IUD prevent pregnancy while in use but do not affect long-term fertility once removed. Uterine artery embolisation may affect future pregnancy outcomes and is not usually a first choice in women planning to conceive.

After Starting Medication

For hormonal treatments and tranexamic acid, improvement is usually seen within one to three menstrual cycles. Spotting or breakthrough bleeding is common in the first months of starting hormonal contraceptives or a hormonal IUD; this typically settles. Regular follow-up — usually within a few months — allows your doctor to assess whether the treatment is working and to check for side effects.

After Hysteroscopic Procedures

Hysteroscopic polypectomy and myomectomy are usually day-care procedures. Mild cramping and light bleeding or watery discharge are common for one to two weeks. Most women return to normal activities within a few days. Sexual intercourse, tampons, and swimming are usually avoided for a short period as advised by your doctor.

After Endometrial Ablation

Watery or bloody discharge is common for several weeks. Cramping is usual on the first day. Most women resume normal activities within a few days. The full effect on menstrual bleeding may take three to six months to become clear.

After Myomectomy or Hysterectomy

These are more substantial surgeries with longer recovery. Recovery from laparoscopic or robotic surgery is generally faster (around 2 to 4 weeks for most activities) than from open abdominal surgery (around 6 weeks). Specific advice on lifting, driving, work, and intercourse will be given by your surgical team based on the approach used.

Treating Anaemia

If AUB has caused iron deficiency or anaemia, treating this is an important part of recovery regardless of which AUB treatment you have. Iron tablets, dietary advice, or in some cases intravenous iron may be used. Energy levels often improve significantly once both the bleeding and the anaemia are addressed.

Risks and Possible Complications

All treatments carry some risk, which should be discussed in detail with your treating doctor.

• Medications: hormonal therapies can cause mood changes, breast tenderness, headache, nausea, irregular spotting, and (with combined oestrogen-containing products) a small increased risk of blood clots in some women. Tranexamic acid is generally well tolerated. NSAIDs can affect the stomach and kidneys with long-term use.
• Hysteroscopic procedures: rare risks include infection, uterine perforation, and fluid overload from the fluid used to distend the uterus.
• Endometrial ablation: bleeding may not improve as much as hoped, may return over time, or in some cases the procedure may need to be repeated. Pregnancy after ablation is unsafe.
• Myomectomy: bleeding, infection, scar tissue formation, and a small chance of needing hysterectomy if bleeding cannot be controlled. Fibroids can also recur.
• Hysterectomy: bleeding, infection, injury to nearby organs (bladder, ureter, bowel), anaesthesia-related risks, and end of fertility. Long-term effects depend on whether the ovaries are removed or preserved.
• Incomplete symptom relief: any treatment may fail to fully control bleeding, requiring a change of approach.

Monitoring and Long-Term Outlook

With accurate diagnosis and appropriate treatment, most women with AUB achieve good symptom control. Long-term follow-up depends on the cause and the treatment.

• Women on long-term hormonal treatment usually have annual or six-monthly review.
• Women with fibroids that were not removed may need periodic ultrasound to monitor size.
• Women with endometrial hyperplasia need close surveillance because of the risk of progression to cancer.
• Postmenopausal women with prior AUB should report any new bleeding promptly.
• Iron status should be rechecked after treatment to confirm anaemia has resolved.

Many women find that controlling AUB has effects beyond the bleeding itself — better energy, improved exercise tolerance, better sleep, and more comfortable participation in work and family life.

AUB in Adolescents

Heavy or irregular bleeding in teenagers is common in the first two to three years after periods begin, because the hormonal axis that controls ovulation is still maturing. This often improves on its own. However, several points are specific to adolescent AUB and worth knowing if you are a parent or a young person reading this on your own behalf.

• Bleeding disorders are more common as a cause in this age group than many people realise. Studies referenced by ACOG suggest that a meaningful proportion of teenagers with very heavy periods from the very first cycle have an underlying bleeding disorder, most commonly von Willebrand disease. Testing for these conditions is part of standard evaluation when heavy bleeding starts at menarche.
• Anaemia can develop quickly and may affect school performance, mood, and concentration. Iron status should be checked.
• Treatment usually starts with medication — hormonal therapy or tranexamic acid — rather than procedures. Hormonal treatment in adolescents is used to regulate cycles and does not cause infertility.
• PCOS can present in the teenage years with irregular cycles, acne, and excessive hair growth, and is an important diagnosis to consider.
• Surgical procedures are very rarely needed in adolescents and are not first-line.

The years leading up to menopause (perimenopause) are a common time for AUB because ovulation becomes irregular. While much of this bleeding is hormonal, the risk of structural causes including endometrial hyperplasia and cancer also rises with age. For this reason, evaluation in this age group typically includes ultrasound and often endometrial sampling, even when the pattern looks hormonal.

Any bleeding that occurs after the menopause — defined as 12 months without a period — should always be evaluated promptly, even if it is light. Postmenopausal bleeding has many possible causes including thinning of the vaginal tissue, polyps, and hormone therapy, but it is also the most common symptom of endometrial cancer, which is highly treatable when caught early.

Living Well with AUB During Evaluation and Treatment

While the underlying cause is being investigated and treatment is starting to work, a few practical steps can help day-to-day life:

• Keep a simple bleeding diary — this is genuinely useful for your doctor.
• Wear layered protection on heavy days and keep supplies on hand at work and in your bag.
• Eat iron-rich foods (leafy greens, lentils, eggs, meat or fish) and take iron supplements if prescribed.
• Stay well hydrated.
• Plan rest around your heaviest days where possible.
• Reach out for support — AUB can be physically draining and emotionally isolating, and talking to someone about it helps.

Frequently Asked Questions

Is AUB common?

Yes. Abnormal uterine bleeding is one of the most common reasons women see a gynaecologist at every life stage. Estimates suggest it affects up to one in three women at some point during their reproductive years.

Does AUB mean I have cancer?

Most causes of AUB are not cancer. However, because cancer of the uterus or cervix can present with abnormal bleeding — particularly after menopause or in women over 45 with persistent symptoms — evaluation is important to rule it out. The earlier these conditions are found, the better the outcomes.

Can AUB be treated without surgery?

In many cases, yes. Medication, including the hormonal IUD, oral hormonal treatments, and tranexamic acid, controls bleeding well for a large proportion of women. Minimally invasive procedures such as hysteroscopic polyp or fibroid removal preserve the uterus. Major hysterectomy is generally reserved for situations where other options have not worked or are not appropriate.

Will treatment affect my ability to have children?

This depends entirely on the treatment. Most medications, treatment of underlying conditions (such as thyroid disease or PCOS), and removal of polyps or submucosal fibroids preserve fertility. Endometrial ablation and hysterectomy end the possibility of pregnancy. It is very important to tell your doctor whether you wish to have children before any decision is made.

How long does it take to know if a treatment is working?

Medical treatments are usually assessed over one to three menstrual cycles. The hormonal IUD continues to reduce bleeding over the first six months. Procedural treatments such as endometrial ablation show their full effect after about three to six months. Your doctor will arrange follow-up to review progress.

I have heavy periods but my mother and grandmother did too. Is it just normal for my family?

Heavy menstrual bleeding can run in families, sometimes because of inherited bleeding disorders such as von Willebrand disease that have never been formally diagnosed in earlier generations. Even when heavy bleeding is “familiar,” it is still worth evaluating, because effective treatment may significantly improve your quality of life.

Can lifestyle changes help?

For some causes, particularly PCOS-related and obesity-related anovulatory bleeding, weight management and exercise can improve cycles meaningfully. Treating thyroid disease and managing diabetes also help. Lifestyle changes are usually part of a broader treatment plan rather than the sole intervention.

Is it safe to use tampons or a menstrual cup if I have AUB?

Generally yes, unless your doctor advises otherwise after a procedure. Some women find pads more practical during very heavy flow because they need changing less frequently than tampons during a heavy episode.

Conclusion

Abnormal uterine bleeding is common, varied in its causes, and in most cases very treatable. The work of evaluation is to find out what is driving your symptom — whether that is a fibroid, a polyp, a hormonal imbalance, a bleeding disorder, or another condition — so that the right treatment can be chosen. Options range from simple medication to minimally invasive procedures to surgery, and the choice depends on the cause, your reproductive plans, your age, and your own preferences.

If you are at the start of this process, the most useful things you can do are to keep a simple bleeding diary, write down the questions you want to ask, and be honest with your specialist about your priorities — whether that is preserving the option of pregnancy, stopping bleeding as quickly as possible, or avoiding surgery if you can. From there, your gynaecologist can help you choose the path that fits your situation best.