| Abstract [eng] |
Monochorionic twins have a unique placental angioarchitecture characterized by the presence of vascular anastomoses connecting the fetuses' circulations. There are three forms of placental vascular anastomoses: arterioarterial, venovenous, and arteriovenous. Imbalanced unidirectional blood flow through vascular anastomoses might cause specific complications of monochorionic twin pregnancies – twin-to-twin transfusion syndrome, twin anemia polycythemia sequence, and twin reversed arterial perfusion. To avoid missing the development of these particular complications during the antenatal period, chorionicity should be determined in the first trimester of the pregnancy. Twin-to-twin transfusion syndrome is caused by abnormal blood flow through arteriovenous anastomoses. As a result, the donor twin develops oligohydramnios, whereas the recipient twin develops polyhydramnios. Twin anemia polycythemia sequence can arise spontaneously or iatrogenically after laser treatment of twin to twin transfusion syndrome. This leads to the donor becoming anemic and the recipient becoming polycythemic. The diagnosis is based on the intertwin differential of middle cerebral artery peak systolic velocity value. The reversed arterial perfusion presents when a pump twin provides all of the circulatory support for the second twin, which has a rudimentary and nonfunctional heart. Specific ultrasound signs considered to be Doppler detected reverse arterial blood flow toward the anomalous acardiac fetus. There are numerous therapeutic methods available, however, the aetiological treatment for all monochorionic twin complications is believed to be the disconnection of the twins' vascular connections. These complications are rare, yet they are linked to greater perinatal mortality, preterm birth rates, and severe postnatal impairment. |
