Monochorionic diamniotic insemination must be completed at 37 weeks

Twin babies with different chorionic villus characteristics are caused by different times of egg cell division. The monochorionic-diamniotic sac splits 4-8 days after fertilization. The embryonic development process is in the service facility stage, that is, the trophoblast has been separated and the amniotic sac has not yet been formed. There is one test tube embryo, and there are only two layers of amniotic membranes between the two amniotic sacs. Because monochorionic and diamniotic twins have more complications, it is very important to identify the chorionic characteristics in early pregnancy. Between 6 and 10 weeks of pregnancy, the chorionic characteristics can be identified based on the number of gestational sacs in the uterus. Because pregnant women with twins have more complications, such as gestational hypertension, gestational cholestasis, placental abruption, polyhydramnios, placental abruption, etc., in order to avoid the occurrence of maternal complications and the occurrence of fetal complications that seriously threaten the lives of mother and child, monochorionic and diamniotic twins without complications and diseases can be delivered under close examination at 35-37 weeks of pregnancy.

For monochorionic and diamniotic fetuses, it is generally recommended to deliver by cesarean section at 37 weeks. Because 37 to 40 weeks of pregnancy are considered full term. Dichotomy and diamniosis do not necessarily end at 37 weeks. Because it is dichorionic and diamniotic, the two fetuses are in two separate amniotic sacs and the impact between them is not too great. The fetus can be born between 38 and 40 weeks of pregnancy. If the first fetus is in the head position, you can choose natural delivery. If the first fetus is in breech or transverse position, a cesarean section is required to end the delivery of the pregnant woman.

If there are no complications, the gestational age for delivery of monochorionic twins is generally 35-37 weeks, usually not exceeding 37 weeks. Since monochorionic twins are conceived with the same test tube embryo and there are vascular overlaps between the embryos, they may have more and more severe complications, and their perinatal morbidity and mortality rates are increased.

1. Twin intravenous injection syndrome: It is a serious complication of monochorionic and diamniotic twins. Based on the arteriovenous connection between the test tube embryos, blood is unilaterally separated from the pulmonary artery to the vein, making one fetus the blood donor and the other fetus the blood recipient, causing anemia and decreased blood volume in the donor fetus, resulting in insufficient renal perfusion, too little amniotic fluid, and even death due to malnutrition; the blood volume of the recipient fetus increases, and congestive heart failure, fetal edema, and polyhydramnios may occur. If twin intravenous injection syndrome is not treated, the fetal mortality rate is as high as 90%.

2. Selective fetal development restriction: This is also a serious complication unique to monochorionic twins.

3. One fetus has no heart defect, which is a rare defect.

4. Anemia and pleiotropy coding sequence syndrome. Therefore, it is recommended that monochorionic diamniotic twins be delivered no later than 37 weeks of pregnancy.