With the increased use of ovulation-promoting drugs and the availability of assisted reproductive technologies, the rate of multiple pregnancies has increased. Multiple pregnancies are high-risk pregnancies, with a significant increase in the incidence of maternal and infant complications, and an increased economic and social financial burden on families. Maternal complications 1. vomiting 2. miscarriage 3. anemia 4. pre-eclampsia – eclampsia: the incidence of twin pregnancies is 3-5 times higher than that of singleton pregnancies. 5, excessive amniotic fluid 6, premature rupture of membranes: leading to preterm labor 7, placenta praevia: leading to vaginal bleeding, sometimes life-threatening 8, placenta abruptio: leads to severe abdominal pain and vaginal bleeding, endangering the life of the pregnant woman and the fetus. 9, intrahepatic cholestasis syndrome during pregnancy is twice as common as singleton pregnancy, and is likely to cause preterm labor, fetal distress, stillbirth and stillbirth. 10, abnormal fetal position 11, weak contractions: easy to cause postpartum hemorrhage. 12, postpartum hemorrhage 13, postpartum depression 14, puerperal infection 2, perinatal complications 1, preterm birth about 50% of twin preterm birth. 2, fetal growth restriction: the incidence of twins is 9 times higher than that of singleton 3, fetal malformation 4, abnormal fetal position: twins lead to higher neonatal mortality, 10 times higher than that of singleton pregnancy. 5, increased incidence of neonatal cerebral palsy 6, umbilical cord prolapse: if the fetus can not be delivered quickly, resulting in fetal death. 7. postnatal cognitive impairment 8. fetal determinism: the poor uterine environment of multiple pregnancies can lead to increased incidence of adult diseases of fetal origin, such as cardiovascular disease, type II diabetes, osteoporosis and psychiatric disorders. For these reasons, aggressive fetal reduction therapy should be performed for multiple pregnancies. A maximum of two fetuses should be retained.