Twin to Twin Transfusion Syndrome, or TTTS, is a disease of the placenta, not the babies.
It affects twins or other multiples that share a single placenta with blood vessels that go from one baby to the other. In about 15% of cases, a shared vessel causes an unequal exchange of blood.
Here, blood from the smaller "donor" twin is transferred to the larger "recipient" twin. The twin that receives the blood is at risk for heart failure. Getting too much blood forces its heart to work harder. The other twin is at risk for loss of blood.
Laser surgery may correct the problem. A laser is endoscopically inserted into the womb. It then burns and seals the interconnecting blood vessels and restores the normal flow of blood.
Following treatment, the babies are regularly monitored.
Review Date 9/7/2021
Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.