Fibroids are common in women of childbearing age, so the effect of fibroids on pregnancy and the effect of pregnancy on fibroids is a great concern for women of childbearing age. Most women who have fibroids before pregnancy can go through the whole pregnancy period smoothly, but the fibroids increase significantly with the weeks of pregnancy, some of them may have vague abdominal pain (mostly seen when the diameter of fibroids is more than 3cm), and even miscarriage, premature delivery, abnormal fetal position and placental abruption may occur. 90% of fibroids will shrink back to their pre-pregnancy state in 3-6 months after delivery. It is generally believed that: fibroids that grow inside the uterus (submucosal fibroids) affect pregnancy; fibroids that grow in the middle of the myometrium (interstitial fibroids) do not affect small fibroids, but large ones do; fibroids that grow outside the uterus do not affect pregnancy in general; fibroids that grow close to the fallopian tubes and press on them may also affect pregnancy. Ding Xilai, Department of Gynecology, Beijing Mizhong Yihe Women’s and Children’s Hospital