The twin-twin transfusion syndrome - an unsolved problem.

Aim: We analysed the data of pregnancies with twin-twin transfusion syndrome (TTTS) in order to identify clinical factors present at the time of diagnosis which can be used to predict the outcome of the pregnancy.

Method: We report prenatal sonographic findings, interventions and outcomes of 28 TTTS pregnancies over a three-year period. Patients were classified into stages of TTTS as follows: Stage I: bladder of donor visible, normal Doppler studies; Stage II: bladder of donor not visible, normal Doppler studies; Stage III: abnormal Doppler studies; Stage IV: hydrops.

Results: In nine pregnancies the infants did not survive the perinatal period (the first 28 days after delivery): the median gestational age at delivery was 24 (range 21 - 29) weeks; six of these nine pregnancies (66 %) were classified as stages III or IV. In five pregnancies one infant survived the perinatal period: the median gestational age at delivery was 28 (range 27 - 32) weeks; four of these five pregnancies (80 %) were classified as stages III or IV. In 14 pregnancies both infants survived the perinatal period: the median gestational age at delivery was 30.5 (range 28 - 39) weeks; two of these 14 pregnancies (14 %) were classified as stages III or IV.

Conclusion: In pregnancies complicated by TTTS, the results of Doppler studies at the time of diagnosis represent the most important clinical factor predicting the outcome of the pregnancy. At the time of delivery, however, the predicted outcome is most directly linked to the gestational age.