The main risk factors include cord entanglement, congenital malformations and very early preterm birth. After 32 weeks, the mortality rate has been reduced to about 5%. The most common problem for MCMA is the entanglement of the umbilical cord in both fetuses, with an incidence as high as 40-80%. If the fetus is mobile and the cord is thin, the cord may become knotted at any time, resulting in interruption of cord blood flow and intrauterine death, especially in midtrimester. However, there is no way to predict when this unexpected event will occur. Therefore, it is recommended to perform dexamethasone at 28 weeks to promote fetal lung maturation and to start fetal heart monitoring at around 32 weeks, and if it can persist until 34 weeks, cesarean delivery is an option to terminate the pregnancy. Of course, there is no more mature domestic guideline opinion on the management of MCMA during pregnancy at present, most of them are expert consensus, and there is no multicenter study with larger sample internationally, so the timing of pregnancy monitoring and termination of pregnancy in MCMA needs to be individualized, and it is recommended to refer to a medical center with experience in the diagnosis and treatment of twin pregnancies for obstetrical examination. In addition, abnormal placental vascular development in single amniotic sac twins leads to an increased risk of abnormal cardiovascular development in both children, so fetal echocardiography is recommended at about 24 weeks and referral to the neonatology department for further examination after birth. For special problems in MCMA, if a fetus with severe anomalies may cause increased incidence of preterm delivery and premature rupture of membranes, the patient may choose to perform a reduction procedure, which requires fetoscopic cord ligation-cutting. However, twin MCMA fetuses with simple cord entanglement are not an indication for fetoscopic reduction.