What is the risk of death to the surviving twin in monochorionic twins if one twin demises?

In monochorionic twin pregnancies, the twins share the same placenta and often share vascular connections, which can lead to significant complications. If one twin dies, a condition known as "twin-to-twin transfusion syndrome" can occur, where the surviving twin may be at risk due to the hemodynamic changes that result from the demise of the other twin.

The risk of death for the surviving twin after the demise of one twin in a monochorionic twin pair is notably higher than in dichorionic twins due to these shared vascular connections. Studies have indicated that the risk of the surviving twin dying can range significantly, but many sources cite a risk of approximately 15% to 18%. This figure encompasses the potential impacts on the surviving twin's blood supply, development, and possible complications arising from the shared placenta.

Therefore, knowing that the risk of death to the surviving twin after the demise of one twin is often reported to be around 15%, it aligns closely with the option of 18%, acknowledging the serious implications that arise in such pregnancies. Recognizing this risk is crucial for managing monochorionic twin pregnancies to optimize outcomes for the surviving twin.