Effect of a prior amniocentesis in patients undergoing laser therapy for twin-twin transfusion syndrome

Abstract

FOR TWIN-TWIN TRANSFUSION SYNDROME RAMEN CHMAIT, CRISTINA ROSSI, RUBEN QUINTERO, Florida Institute for Fetal Diagnosis and Therapy, Tampa, Florida OBJECTIVE: To assess the implications of a previous therapeutic amniocentesis (PTA) in patients that subsequently underwent laser therapy for twin-twin transfusion syndrome (TTTS). STUDY DESIGN: All twin pregnancies that underwent laser therapy for TTTS from January 1999 through December 2003 were studied. Patients with no PTA (PTA-) were compared to those with one or more PTA’s (PTA+) in regards to demographics, operative complications, and outcome measures including gestational age at delivery and survival of at least one neonate. Statistical significance was determined if P ! .05. RESULTS: Three hundred and forty patients underwent laser therapy for TTTS during the study period. Of these, 203 (60%) were PTAand 137 (40%) were PTA+. The median number of amniocenteses in the PTA+ group was 1 (range 1-6), with a median total volume withdrawn of 1550cc (range 100-12000). Severity of the disease was similar between the two groups in terms of Quintero stages I/II and stages III/IV. On average, the PTAgroup underwent surgery one week earlier than the PTA+ group (20.1 vs. 21.2 weeks’ gestation, P = .0001). Placental location was anterior more often in the PTA(49%) than in the PTA+ (36%, P = .019) group, yet amnioexchange to correct blood discolored amniotic fluid was necessary less often in the PTA(9%) than in PTA+ (20%, P = .009) group. Gestational age at delivery was greater in the PTAthan in the PTA+ patients (32.0 vs. 30.6 weeks, P = .008), with a trend towards improved survival (89% vs. 81%, P = .0543). CONCLUSION: Therapeutic amniocentesis prior to laser therapy is associated with increased operative risk, earlier gestational age at delivery, and a trend towards lower perinatal survival. Patients with TTTS who desire laser therapy should avoid undergoing prior therapeutic amniocenteses.