Abnormal uterine bleeding: heavy, long, irregular or unexpected bleeding explained

Doctors look at volume, length, timing and predictability. The NHS lists signs that periods may be heavy: changing a pad or tampon every 1 to 2 hours, using two types of product together, periods longer than 7 days, clots bigger than about 2.5cm (roughly a 10p coin), flooding onto clothes or bedding, and feeling tired or short of breath.

On timing, the NHS defines irregular periods as a gap of less than 21 days or more than 35 days between periods starting. Bleeding between periods or after sex is a separate pattern and is always worth reporting. NICE stresses that what matters most is the effect on quality of life, rather than a precise measurement of blood loss.

The NHS says heavy periods can be normal at certain life stages but can also be caused by conditions of the womb or ovaries, bleeding disorders, and certain medicines. Irregular periods have a different set of common causes.

The NHS suggests seeing 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. Persistent irregular cycles, periods lasting more than 7 days, or irregular periods with symptoms such as weight gain, tiredness, facial hair growth or trouble getting pregnant also merit a visit.

For pelvic inflammatory disease the NHS gives emergency advice: pelvic pain with heavy vaginal bleeding, sudden intense lower abdominal pain, dizziness or fainting, or a very high temperature need 999 or A&E. Heavy bleeding with collapse, severe pain or pregnancy should never wait for a routine appointment.

NICE guidance on heavy menstrual bleeding lays out a stepwise approach. A GP takes a history covering the nature of the bleeding, any bleeding between periods, pelvic pain or pressure, and impact on daily life. If heavy bleeding is the only issue, treatment can often start without an examination, unless a hormonal coil is planned.

Everyone with heavy periods should have a full blood count. Coagulation tests are considered if heavy periods have been present since the first period and there is a personal or family history of a bleeding disorder. NICE says not to test female hormones, and not to test thyroid hormones unless there are other signs of thyroid disease.

• Outpatient hysteroscopy is offered when history suggests submucosal fibroids, polyps or abnormal womb lining, for example with persistent bleeding between periods.

• Pelvic ultrasound is offered if the womb can be felt abdominally, a pelvic mass is suspected, or examination is inconclusive.

• Transvaginal ultrasound is preferred when significant period pain or a bulky tender womb suggests adenomyosis.

• Endometrial biopsy is considered at hysteroscopy for higher-risk groups, such as persistent irregular bleeding, people taking tamoxifen, or when treatment has failed.

• If cancer is suspected, the separate NICE suspected-cancer pathway applies.

NICE suggests considering a levonorgestrel-releasing intrauterine system (hormonal coil) as the first treatment when no cause is found, when fibroids are under 3cm and not distorting the womb, or when adenomyosis is suspected. It advises waiting at least 6 cycles to judge the effect, since bleeding patterns can change in the early months.

If a coil is declined or unsuitable, tranexamic acid and NSAIDs are the non-hormonal options, and combined hormonal contraception or cyclical oral progestogens are the hormonal ones. The NHS adds that prescription-only anti-inflammatories such as mefenamic acid or naproxen may be offered. Treatment is not always needed if bleeding is not troubling you.

When treatment fails, symptoms are severe or tablets are declined, NICE suggests specialist referral for further investigation or surgery, including second-generation endometrial ablation or hysterectomy. Women considering either should have a full discussion first about fertility, sexual feelings, bladder function, need for further treatment and psychological impact, and are advised to avoid pregnancy after ablation.

Prolonged heavy bleeding can lead to iron deficiency anaemia, which is why the NHS says a series of blood tests may be arranged. Persistent tiredness or breathlessness is a reason to mention bleeding patterns even if you have lived with them for years.

Keeping a diary or app log of start dates, length, flow and pain helps clinicians see patterns that are easy to forget in a short appointment.

Most people begin with a GP and move on to gynaecology if treatment fails or a structural cause is suspected. Private gynaecology can offer faster access to ultrasound or outpatient hysteroscopy, with the clinical principles unchanged. It is reasonable to ask what the consultation includes and what happens if a biopsy is needed.