Presentation
Second trimester pregnancy ultrasound. Twins.
Patient Data
MCDA twin pregnancy. The amniotic membrane closely envelops twin 2, due to unequal distribution of amniotic fluid (twin 1 polyhydramnios with DVP 15.4; twin 2 oligohydramnios with DVP 1.6). This is diagnostic of twin-to-twin transfusion syndrome.
Other observations relevant to staging of TTTS are:
- donor twin bladder is visible
- normal dopplers in both twins
- no features of hydrops in either twin
- no features of fetal demise.
Hence, this is stage 1 TTTS.
Limited images of fetal morphology and membranes demonstrate no other abnormality.
Twin 2 is smaller but not growth restricted. EFW discrepancy of 15% is within normal limits.
Case Discussion
Typical oligohydramnios-polyhydramnios appearance of twin-twin transfusion syndrome (TTTS) - stage 1. Note the "stuck" appearance of the oligohydramnios (donor) twin.