Victorian Fetal Therapy Service || Twin to Twin Syndrome

The diagnosis of twin-twin transfusion syndrome is made by finding the following features:

Monochorionic placenta (single placenta shared by both twins)

Fetuses of the same gender

Polyhydramnios (increased amniotic fluid) around the recipient
and oligohydramnios (decreased amniotic fluid) around the donor

Absence of other causes of the abnormal amniotic fluid amounts

There may also be:

Discordance in fetal size

Non-visualization of the donor's bladder with enlarged recipient's
bladder

Abnormal blood flow patterns in arteries or veins within either
or both twins

Signs of heart failure in one or both twins seen as fluid accumulating
around the heart or lungs, in the abdomen, or under the skin.

In the most severe forms the diagnosis is usually not difficult. Careful efforts must be made, however, to differentiate TTTS from other conditions which can have similar features but which require different management.