Twin-to-Twin Transfusion Syndrome
Twin-to-twin transfusion syndrome (TTTS) is a rare but dangerous disease affecting identical twins while they are in the womb.
In TTTS one twin shares their blood supply with the other resulting in the donor twin having too little blood and the recipient having too much.
As a result the donor twin is usually born smaller and paler than the recipient. They may be anaemic (low red blood cell count) and/or dehydrated. A blood transfusion may be needed in order to increase the amount of blood circulating in the donor baby's body.
The twin that received blood from the other in the womb is often born large with red skin. Because of the increased amount of blood in its body it may have a high blood pressure. The danger of this is that it may result in heart problems. The recipient may be offered medication to improve heart function and it may have to have blood removed from its body to reduce the blood pressure.
When identical twins are born significantly different sizes and weights they are referred to as discordant twins.
TTTS can usually be disgnosed by an ultrasound during pregnancy. After birth, further tests carried out on the babies will confirm the diagnosis.
It is possible to intefere with the flow of blood between the two fetuses using fetal laser surgery. However it is likely that the babies will need further treatment after birth. Twins affected by TTTS can make a full recovery but in some more severe cases one or both of the twins may not survive.