What causes heavy periods?

Identifying the underlying cause is important for guiding Dr Sam Daniels’ treatment recommendations but in some cases, no conclusive explanation for your heavy periods can be determined. Abnormally heavy menstrual bleeding causes can be grouped into three main categories.

Hormone problems

An imbalance in the key hormones that regulate your menstrual cycle can interfere with your periods in a number of ways, including causing them to be highly irregular and infrequent or very heavy and prolonged.

Heavy menstrual bleeding can be a sign of hormonal conditions including:

Hypothyroidism (an underactive thyroid)

Polycystic ovarian syndrome (PCOS)

Peri-menopause (the stage of a woman’s life leading up to menopause)

Uterine disorders

Menstrual bleeding originates from the uterus, as the uterine lining (the endometrium), breaks down and is shed from the body during your monthly cycle if you haven’t fallen pregnant that month.

Conditions of the uterus that can cause heavy periods include:

Uterine polyps (small non-cancerous growths in the endometrium)

Uterine fibroids (non-cancerous growths in the muscle of the uterus wall)

Adenomyosis (abnormal growth of endometrial tissue into the uterus muscle)

Endometriosis (abnormal growth of endometrial tissue around other pelvic structures)

Uterine cancer or precancerous changes

Blood clotting problems

You may be more likely to experience heavy menstrual bleeding if you have a blood clotting disorder such as haemophilia, or if you’re taking blood thinning medication. When no underlying cause of heavy periods can be identified, it may be due to a bleeding disorder of the endometrium. Unfortunately, there are currently no tests that can confirm this diagnosis.