The exact cause of fibroids is unknown, but hormones and growth factors seem to play a role. The growth of the fibroids depend on the presence of estrogen and progesterone. Hormonal birth control, hormone therapy , and the hormones of pregnancy can all cause fibroids to grow more rapidly. Most fibroids shrink after menopause.

Risk factors for the development of uterine fibroids include:

  • Never being pregnant
  • Getting your first period at a young age
  • More frequent periods
  • Menstrual pain
  • Family history of uterine fibroids
  • African descent
  • Obesity
  • Age (most common between 40-50 years)
  • High blood pressure
  • Diabetes