Twin to twin transfusion syndrome (TTTS) is a rare condition but also a serious one. This condition happens when the identical twins share the same placenta. When this happens then the blood vessel connections get abnormal and it causes the blood to not flow evenly between both the babies. One of the twins who is the donor becomes dehydrated and the other twin who is the recipient gets a high blood pressure. The second twin produces lots of urine that fills up the amniotic sac.
TTTS is a disease that gets formed in the placenta of the pregnant woman and thus this is not a disease that occurs in the babies. The condition affects the twins in different ways. The twin who is the donor does not produce sufficient quantities of urine and thus has low amniotic fluid levels which lead to low growth. The second twin or the recipient twin has too much of fluid and this twin produces more urine. This causes a big bladder and the recipient twin has an excess of amniotic fluid. The excess of the amniotic fluid at times puts a lot of pressure on the heart and this could cause heart failure.