Which are the causes of Twin-Twin Transfusion Syndrome?

Twin-Twin Transfusion Syndrome (TTTS) is a rare condition that affects identical twins who share a placenta in the womb. It occurs when there is an imbalance in the blood flow between the twins through the shared placenta, leading to one twin receiving too much blood (the recipient) and the other twin not receiving enough blood (the donor).

The exact cause of TTTS is not fully understood, but there are several factors that are believed to contribute to its development:

1. Placental sharing: TTTS occurs in pregnancies where identical twins share a single placenta. The placenta contains blood vessels that supply nutrients and oxygen to the developing fetuses. In TTTS, the blood vessels in the placenta are not evenly distributed between the twins, leading to an unequal blood flow.

2. Abnormal blood vessel connections: In some cases, the blood vessels connecting the twins in the placenta may be abnormal. This can result in an uneven distribution of blood flow, with one twin receiving more blood than the other.

3. Size and position of the placenta: The size and position of the placenta can also play a role in the development of TTTS. If the placenta is larger or positioned in a way that affects blood flow, it can contribute to the imbalance in blood distribution between the twins.

4. Genetic factors: There may be genetic factors that increase the risk of developing TTTS. Research suggests that certain genes may be involved in the development of abnormal blood vessel connections in the placenta.

5. Environmental factors: While the exact environmental factors that contribute to TTTS are not known, it is believed that factors such as maternal age, smoking, and certain medications may increase the risk of developing the condition.

6. Random chance: In some cases, TTTS may occur randomly without any identifiable cause. It is important to note that TTTS is not caused by anything the mother did or did not do during pregnancy.

It is crucial for expectant mothers of identical twins to undergo regular prenatal check-ups and ultrasounds to monitor for the development of TTTS. Early detection and intervention can significantly improve the outcomes for both twins. Treatment options may include laser surgery to seal off abnormal blood vessels in the placenta or amnioreduction to remove excess amniotic fluid.