Fibroid tumors are benign smooth muscle tumors of the uterus and occur in 20-30% of women of reproductive age. Your risk for developing fibroids increase with elevated BMI, early first menses and lack of child bearing. Its incidence is also increased in African American women. Pregnancy appears to protect against the development of fibroid tumors reducing your risk for about 10 years after birth. These tumors contain both estradiol and progesterone receptors which is why women have a significant decrease in the size of these tumors after menopause.