REVISITING THE CLINICAL EFFICACY OF CERCLAGE IN THE TREATMENT OF SECOND-TRIMESTER SONOGRAPHICALLY DETECTED PREMATURE DILATION OF THE INTERNAL OS

OBJECTIVE: To compare perinatal outcome of patients with sonographic internal os dilation and cervical distal shortening in second-trimester pregnancies treated with cerclage vs no cerclage. STUDY DESIGN: From May 1998 to June 2000 patients between 16 and 24 weeks’ gestation with the following sonographic criteria: (1) internal os dilation, (2) membrane prolapse into the endocervical canal, (3) shortened distal cervix, (4) response to transfundal pressure, and (5) no prolapse beyond the external os; were randomly assigned to McDonald cerclage or expectant management. Before randomization, all patients received an amniocentesis, multiple urogenital cultures, and 48 hours of indomethacin and antibiotic therapy. After randomization and treatment, each patient had therapy discontinued and was treated with outpatient bed rest and weekly cervical ultrasounds. A rescue cerclage was offered to any patient ≤24 weeks who had membranes beyond the external os. Cerclages were removed with PPROM, PTL unresponsive to tocolysis, or at 36 weeks’ gestation. RESULTS: Of the 113 patients, 55 were randomized to cerclage and 58 to no cerclage. There were 8 rescue procedures (4 cerclage and 4 no cerclage). There was no difference noted with respect to risk factors for preterm birth, gestational age at diagnosis, cervical measurements at entry, or perinatal outcome. The survival curve was generated with respect to gestational age at delivery, which showed no significant difference between groups. CONCLUSION: This study reaffirms the finding of no improvement in perinatal outcome with the utilization of McDonald cerclage for second-trimester sonographic evidence of premature cervical dilation