What causes heavy periods?

Adenomyosis occurs when tissue similar to the uterine lining grows into the uterine muscle and can cause heavy, painful periods. Endometrial polyps are growths from the uterine lining that may bleed irregularly. Fibroids can change the shape of the uterus and increase menstrual flow.

Ovulation and hormone changes may make the uterine lining build up more than usual before it sheds. Some medicines, including blood-thinning medicines, can increase bleeding. A bleeding disorder can also be relevant, especially when heavy periods have been present since the first periods or there is easy bruising. Repeated heavy bleeding may lead to iron-deficiency anaemia, causing tiredness or breathlessness.

Keep a brief record of bleeding, clots, pain, cycle timing and missed activities, and arrange a medical review if periods interfere with daily life or leave you exhausted. Assessment may include a blood count, iron testing, pregnancy testing when relevant, a pelvic examination and ultrasound.

Treatment is matched to the cause and your pregnancy plans. Options may include tranexamic acid, hormonal treatment, removal of a polyp, myomectomy, uterine artery embolisation or hysterectomy. Read about [Heavy Periods](/symptoms/heavy-periods/), [Adenomyosis](/conditions/adenomyosis/), [Endometrial Polyps](/conditions/endometrial-polyps/) and [Iron Deficiency Anaemia](/conditions/iron-deficiency-anaemia/).

Seek urgent care if bleeding is so heavy that you feel faint, weak or short of breath, or if severe pelvic pain accompanies bleeding. Arrange prompt review for bleeding between periods, after sex, after menopause or during a possible pregnancy.

Ask whether you need blood tests for anaemia or a scan for adenomyosis, fibroids or polyps. Discuss how each treatment affects fertility, contraception, pain and future pregnancy, and ask what bleeding pattern should prompt urgent help.