Uterine fibroids
Benign smooth-muscle tumours of the myometrium grow under the drive of oestrogen and progesterone, which is why they enlarge through the reproductive years and regress after the menopause, distorting the uterus and disrupting normal menstrual haemostasis as they grow.
First principles
Fibroids are oestrogen- and progesterone-dependent tumours
Each fibroid arises from a single myometrial smooth muscle cell that has undergone a monoclonal proliferation, and its growth is sustained by circulating oestrogen and progesterone acting on receptors within the tumour. This single fact explains their entire natural history: they emerge and enlarge during the reproductive years when sex hormone levels are high, often grow further during pregnancy, and characteristically shrink once oestrogen falls after the menopause.
Educational content pending clinical review. Not medical advice.