Partial rotunda does not cause fetal abnormalities, while complete rotunda is most dangerous in late pregnancy, from the 7th month of pregnancy to delivery, when painless bleeding, miscarriage, preterm delivery, and less-than-fetal-age babies may occur. Rotunda is an irregular placenta with a low incidence, including partial and complete type of placenta. The complete type may have painless vaginal bleeding or complications during pregnancy, which in turn may affect the fetal nutrient absorption. It is more dangerous in late pregnancy, i.e. after the 7th month of pregnancy, and may result in placental abruption, intrauterine growth retardation, and preterm delivery, which are associated with increased perinatal morbidity and mortality and should be monitored. In general, the incidence of rotund placenta is low, mostly partial, and partial rotund placenta basically does not affect pregnancy, so pregnant women do not need to worry too much, but they should try to ensure that the fetus needs sufficient nutrition for intrauterine development.