SURVEILLANCE AND MANAGEMENT OF TTTS AND TRAP IN MCDA TWINS

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Bence Csapo, Philipp Klaritsch

School of Medicine University of Graz

Key words: Twin to Twin Transfision Syndrome, Twin Anemia et Polycytemia Sequence, surveillance, management

SUMMARY. Multiple pregnancies pose unique challenges for many obstetricians. The average number of children in families has drastically reduced and women tend to decide to have children later in life than even a few decades ago. These facts mean, that the time window to have children is getting ever shorter and also that the number of twin and higher-grade multiple pregnancies continues to rise. As soon as the diagnosis of chorionicity of a multiple pregnancy is made clear guidelines should be followed for counseling, surveillance and for possible management of eventual complications. These guidelines have evolved over the last 10–15 years to a level, where early diagnosis, individual counseling are possible. In these cases timely referral to a management center can significantly improve the survival rates of these pregnancies. It cannot be emphasized often enough, that it is the chorionicity and not the amnionicity of a twin pregnancy, which determines the risks and therefore the management of these pregnancies. The root of all possible complications in monochorionic pregnancies are the random connection of fetal blood vessels on the placental surface, and also a similarly random and unequal sharing of the placenta. Depending on the combination of these factors different pathologic conditions can occur. In case of sub acute and acute AV anastomosis the classic twin-to-twin transfusion occurs. This is a massive volume shift between the twins. This happens in about 10% of al MCDA pregnancies. The trusted staging system recommended by Quintero helps us to assess the stage of the disease. The only causal therapy for TTTS is the functional di-chorionising of the placenta. This is done by coagulating the abnormal placental vessels using LASER light. The majority of these procedures result in the survival of both, but at least one of the twins. When the blood exchange between the fetuses slowly and chronically occurs, we usually do not see signifi cant volume shift as in TTTS, but there is a considerable difference in the hemoglobin counts of the fetuses. This condition is called TAPS (twin-anemia-polycytemia-sequence). This condition can also be managed by fetoscopic laser photocoagulation, but as a reasonable alternative an intrauterine blood transfusion will be offered. The talk presents guidelines and recommendations for the evidence based surveillance and management of TTTS and TAPS in monochorionic pregnancies.