Heavy or Irregular Periods and Abnormal Bleeding

What counts as heavy or irregular

Heavy bleeding (medically called menorrhagia) and irregular periods are common, and they can be normal for you. The NHS describes heavy periods as needing to change a pad or tampon every 1 to 2 hours, needing two products together, periods lasting more than 7 days, passing clots larger than about 2.5 cm, or bleeding through clothes or bedding. Tiredness or shortness of breath can also be signs. [1]

The NHS calls periods irregular when the gap between them is under 21 days or over 35 days. [2]

Common causes

• Life stage: periods can be heavy or irregular when they first start, after pregnancy, or approaching menopause. [1]
• Conditions of the uterus or ovaries: PCOS (now also called PMOS in some places), fibroids, endometriosis, adenomyosis and pelvic inflammatory disease. [1] See PCOS and endometriosis and fibroids.
• Bleeding disorders and medicines: such as von Willebrand disease, some blood thinners and chemotherapy. [1]
• Lifestyle and hormonal factors: big changes in weight, stress, too much exercise, thyroid problems, and some hormonal contraceptives. [2]
• Rarely, heavy bleeding can be a sign of uterine cancer, which is one reason persistent changes should be checked. [1]

Iron and anemia

Heavy periods raise the chance of low iron. [3] Iron deficiency anemia can cause tiredness, shortness of breath, palpitations and pale skin. [4] A clinician usually checks with a blood test and recommends iron tablets if the count is low. [4] Because too much iron can cause harm, do not start high-dose iron on your own. [3] See nutrition for women.

Treatments with evidence

The NHS says heavy periods do not always need treatment, but options include a hormonal intrauterine system, the combined pill, tranexamic acid, and prescription anti-inflammatory medicines. [1] A Cochrane overview found that the hormonal IUS gave a large reduction in blood loss (low certainty), and antifibrinolytics such as tranexamic acid probably reduce blood loss (moderate certainty). [5] Specialist options include endometrial ablation, fibroid removal and hysterectomy. [1]

Complementary approaches: we did not find reliable evidence in the sources we read for herbs or supplements as a treatment for heavy bleeding. Proper evidence not found. NCCIH says one low-quality study suggested chasteberry might reduce IUD-related heavy bleeding, but this is not enough to recommend it. [6]

Keeping track

A diary or app that records start dates, length, flow and pain helps a clinician. [2]

When to get help

See a clinician if heavy periods affect daily life, have lasted a long time, come with severe pain, or if you bleed between periods or after sex. [1] See someone if periods last longer than 7 days. [2] Any bleeding after menopause needs checking, even once. [7] Heavy vaginal bleeding with faintness or dizziness is an emergency: call 911. [8] See abnormal bleeding and when to get help and the menopause page.