Twin-Twin Transfusion Syndrome (TTTS)

Twin-Twin Transfusion Syndrome (TTTS) is a condition that affects identical twins who share a single placenta during pregnancy. It involves an imbalance in blood flow between the twins through shared blood vessels, causing one twin to receive too much blood and the other too little. This imbalance primarily affects the circulatory system and can lead to serious complications for both babies. The twin receiving excess blood may develop heart strain and excess amniotic fluid, while the other twin may suffer from growth restriction and low amniotic fluid. Early detection is important because the condition can rapidly worsen and impact the health and survival of both twins. The syndrome is unique to monochorionic twin pregnancies, where the twins share a placenta.

Twin-Twin Transfusion Syndrome (TTTS) is a serious complication of monochorionic diamniotic twin pregnancies characterized by unbalanced blood flow through vascular anastomoses in the shared placenta. This results in a donor twin who becomes hypovolemic and growth restricted due to decreased blood volume and amniotic fluid (oligohydramnios), and a recipient twin who becomes hypervolemic with polyhydramnios and cardiac overload. The pathophysiology involves abnormal arteriovenous shunting between the twins' circulations, leading to discordant hemodynamics and potential fetal demise. TTTS is clinically significant due to its high risk of perinatal morbidity and mortality if untreated. It typically presents in the second trimester and requires careful monitoring and intervention to improve outcomes.