Monochorionic bimaculature refers to a condition in which there is only one layer of chorionic membrane separating the two amniotic cavities and the two fetuses share a placenta, which is an identical twin. The first four months of pregnancy are particularly dangerous because of the shared placenta and the vascular traffic between the two fetuses, which can lead to blood transfusion from one fetus to the other, and the ultrasound should be performed once every four weeks before 16 weeks of pregnancy and once every two weeks after that. If there is too much amniotic fluid in one fetus and too little amniotic fluid in another fetus, it is necessary to consider the possibility of combined twin fetus transfusion syndrome, and in serious cases, fetal edema and fetal death can occur; 2. selective growth restriction: two children share a placenta, and the uneven share of the placenta or abnormal insertion of the umbilical cord in both fetuses can produce uneven absorption of nutrients, and if there is a significant difference in fetal size, consider the possibility of combined twin fetus selective growth restriction; 3. no heart The sequence of teratology sign: due to reverse arterial perfusion, one of the twin fetuses appears to have a heartless teratology with no upper body development; 4. The sequence of twin fetuses with anemia and erythropoiesis: due to continuous infusion of red blood cells from one fetus to the other fetus, resulting in anemia in one fetus and an increase in red blood cells in the other fetus; this complication can be monitored by testing the peak flow rate of the middle cerebral artery in the fetus during pregnancy. It is recommended that pregnant women with single chorionic twin sheep undergo strict obstetric examination during pregnancy and have regular ultrasound monitoring of the twin fetuses for early detection of complications. In addition, it is necessary to ensure adequate nutrition during pregnancy, especially protein, iron, folic acid, etc., control the intake of sugar and carbohydrates, and follow medical advice to exercise appropriately to prevent anemia, hypertension, gestational hyperglycemia and preterm delivery. In late pregnancy, attention should be paid to avoid overworking, and timely fetal heart monitoring is needed to prevent hypoxia.