Cervical cerclage in the treatment of incompetent cervix. A retrospective analysis of the indications and results of 164 operations.

Abstract

Between 1959 and 1968 a cervical cerclage operation was performed 163 times in 159 women because of assumed cervical incompetence. The operation was carried out during pregnancy 156 times, and 3 times in a nonpregnant patient. 4 women had two operations during the same pregnancy. The operations represent 1 in 404 deliveries at the hospital during the study period. The diagnosis of cervical incompetence was based on the history of previous pregnancies in 99 cases (79%). The finding of a short and open cervix was made 85 times (68%), and the diagnosis was supported by the hystero‐graphic findings in 11 cases (9%). The average duration of gestation at the time of operation was 14 weeks, and the average total duration of the pregnancies was 35 weeks. The previous foetal salvage rate was 30.8%, and the final success rate 83.2%. The comparable rates for normal deliveries without cervical cerclage at the same clinic were 74.7% and 97.1%, respectively. The abortion rate in the series after treatment was 13.6%. Premature deliveries with loss of the child occurred 4 times, leading to a perinatal mortality rate of 3.2%. Breech presentation was found 10 times (6.3%). Caesarean section was undertaken 23 times (18%) in 21 patients. The ratio of the final success rate and the previous foetal salvage rate (foetal salvage ratio) in the whole series was 2.7, and in the randomly selected cases 1.3. This ratio was the highest (3.8) between 26 and 30 years, and when the operation was performed between the 16th and the 19th weeks of pregnancy (3.3). The minimum benefit rate of the operation was 30% [80.2–30.8 – (97.1–74.7)]%. This rate is little affected by unnecessary operations, while difference between the foetal salvage ratios in the operation and the control materials is greatly affected by them. This difference was 1.4 (2.7–1.3) in this material. The differences in abortion rates, laws and standards of obstetric care lead to differences in the materials. Therefore the following criteria are suggested to be included in the reports concerning cervical cerclage operations: Number of operations per number of deliveries in the study period Final success rate of the series Previous foetal salvage rate Foetal salvage ratio (the ratio of no. 2 and no. 3) Final success rate and previous foetal salvage rate among the mothers without a cervical suture in the same hospital at the same study period Foetal salvage ratio from no. 5 Difference between foetal salvage ratios in the operation and the control groups Minimum benefit rate in the operation material