Amniocentesis for selection before rescue cerclage

Objective: To determine whether diagnostic amniocentesis should be part of evaluations of women under consideration for rescue cerclage. Methods: We reviewed the obstetric records of 25 candidates for rescue cerclage seen between June 30, 1995, and July 1, 1997. Rescue cerclage was defined as a procedure on a cervix with an internal os dilated at least 2 cm and 50% effaced, with membranes visible at the external os. Transabdominal amniocentesis was offered as part of the preoperative evaluation, and amniotic fluid (AF) was sent for glucose and lactate dehydrogenase level determinations, Gram staining, and culture for aerobic and anaerobic bacteria. Placentas were examined for histopathologic evidence of inflammation. The women were divided into three groups. Eleven women had rescue cerclage after amniocentesis, seven had rescue cerclage after declining amniocentesis, and seven had amniocentesis but were treated conservatively because of AF markers of infection. Analysis of variance and chi(2) statistics were used. Results: The group that had rescue cerclage after amniocentesis had a significantly longer mean admission-to-delivery interval, higher mean gestational age at delivery, higher mean birth weight, and higher neonatal survival rate than did the group that had rescue cerclage without amniocentesis and the group that had no cerclage after amniocentesis (P <.001). Conclusion: Amniocentesis before rescue cerclage placement identified women with subclinical chorioamnionitis who would not benefit from cerclage. (Obstet Gynecol 2000;95:652-5. (C) 2000 by The American College of Obstetricians and Gynecologists.).