Multiple pregnancy reduction is a technique that has been developed in response to the significant increase in the incidence of multiple pregnancies in recent years, especially in women undergoing IVF, where more than one embryo is transferred to ensure success, and where multiple pregnancies are more likely to occur. In multiple pregnancies, reduction can be an effective and safer way to achieve a successful delivery. Many pregnant mothers feel that the more pregnancies they have, the better, and that one pregnancy can solve the problem of multiple children. The risks during pregnancy and delivery increase with the number of fetuses, which is a serious threat to the life of the mother and child, and the perinatal mortality rate of the fetus increases greatly. There are many complications in multiple pregnancies compared to singleton pregnancies: 1. miscarriage. The more fetuses there are, the greater the rate of miscarriage during early pregnancy, and the rate of miscarriage in twin pregnancies is 2-3 times that of singleton pregnancies. 2. Hypertensive disorders during pregnancy. The onset of hypertensive disorders during pregnancy in multiple pregnancies is earlier than in singleton pregnancies, and the onset is rapid and serious, and not easy to control, seriously threatening the lives of mothers and children. 3, excessive amniotic fluid. The incidence is more than 12% of singleton pregnancies, which is related to fetal malformations and twin fetal transfusion syndrome. 4, anemia. Due to the increase in blood volume, multiple pregnancies have more symptoms of anemia in late pregnancy, and anemia can lead to the occurrence of intrauterine fetal growth retardation. 5, placenta praevia. As the placenta of multiple pregnancies is larger and has a wider attachment surface, it is prone to placenta praevia. 6, postpartum hemorrhage and puerperium. Due to the large attachment surface of the placenta, it affects the contraction of the uterus and causes postpartum hemorrhage, and the chance of puerperal infection caused by prolonged hemorrhage is also greatly increased.