What exactly is Twin-to-Twin Transfusion Syndrome?
The medical definition of twin-to-twin transfusion syndrome (TTTS) is an unbalanced blood flow between monochorionic (MC) fetuses. But let’s break down what that means. Monochorionic twins are twins who share the same placenta, which means they also share blood vessels that distribute blood-flow between each baby. For reasons that are actually unknown, 10% to 15% of MC twin fetuses will develop an uneven flow of blood between the shared blood vessels, resulting in TTTS. So what exactly happens to babies with TTTS? The smaller twin (a.k.a. the “donor twin”) doesn’t receive enough blood, while the larger twin (a.k.a. the “recipient twin”) becomes overloaded with too much blood. In an attempt to reduce its blood volume, the recipient twin will up the amount of urine it produces, which causes its bladder to grow large and too much amniotic fluid to surround it. At the same time, the donor twin will produce an unusually low amount of urine and the amniotic fluid around the twin will lessen
