Amnioreduction versus septostomy in twin-twin transfusion syndrome

The purpose of this study was to compare treatment outcomes in pregnancies affected with twin-twin transfusion syndrome. Treatment consisted of serial amnioreduction or septostomy.

A retrospective review of patients who were diagnosed with twin-twin transfusion syndrome from June 1998 to June 2000 was conducted. Diagnosis was based on polyhydramnios (maximal vertical pocket, >8 cm) in conjunction with an enlarged fetal bladder, oligohydramnios (maximal vertical pocket, <2 cm) with nonvisualization of the fetal bladder, and documentation of a single placenta. Data evaluated were gestational age at enrollment and delivery, prolongation of gestation, and number of surviving fetuses by treatment modality.

There were 7 patients in the amnioreduction group and 7 patients in the septostomy group. The mean gestational age at enrollment for amnioreduction was 21.0 weeks and for septostomy was 18.0 weeks (P =.01). There were 67% 2-twin survivors in the septostomy group (P = not significant), but an overall equal number of survivors (78%) in both treatment groups. The rate of no surviving twins was equal (14%) in both groups. Pregnancy was prolonged an average of 12 weeks in the septostomy group and 6.5 weeks in the amnioreduction group (P =.007). The average gestational age at delivery was 27.5 weeks for the amnioreduction group and 30.0 weeks for the septostomy group (P =.08).

The prolongation of pregnancy from diagnosis to delivery was statistically significant for septostomy when compared to amnioreduction. Although not statistically significant, there appears to be a trend toward increasing gestational age at delivery with septostomy. Further randomized studies are warranted for septostomy as a treatment modality in twin-twin transfusion syndrome.