Prediction of Pregnancy Successes by Measuring Diameter of Cervical Cerclage in Patients with History of Recurrent Mid Trimestric Abortion

Objectives: To determine the best diameter needed to be reached by the operator during cerclage operation to have best prognosis of pregnancy in pregnant patients with a history of recurrent midtrimester abortion.Setting: Al-Nahda Hospital (100 beds) in association with, Prince Sultan Military Hospital. The protocol of the study was approved by the study and research committees of both hospitals.Population: 32 patients with history of recurrent mid trimester pregnancy loss, who had undergone cerclage operation in the period between December 2006 and January 2008.Outcome measures duration of pregnancy. A successful operation is considered if it would result in a pregnancy of more 36 weeks.Patients and Methods: 32 patients with a history of recurrent mid trimester abortions. A transvaginal cervical cerclage was done at a pregnancy of 13 to 16 weeks. Different gynecologists did the operation using the same technique (McDonald s). Merseline tape was used in all patients. Transabdominal 3D ultrasound was done to all patients postoperatively during the antenatal care. The 3D volume scanning allowed good evaluation of the diameter of the cerclage ring. Follow-up patients was done till time of delivery of the fetus. Different factors were assessed and statistically correlated with gestational age included gravidity, parity, cervical length, protrusion of membranes through the cervical canal in addition to the diameter of the cervical cerclage.Results: The mean diameter of the cervical cerclage was 1.96±0.29cm in the successful group and 2.29±0.18cm in the failed group. The mean gestational age reached was 37.8.0± 0.9W in the successful group and 26.95±1.88W in the other group. There was a significant negative correlation between the diameter of the cervical cerclage and the duration of the pregnancy with p 0.001 but with a poor predictive value (R2=0.29). The lowest diameter of cerclage recorded is 1.85cm with low sensitivity (59%) and specificity (33%). However, 1153 the largest cutoff diameter accepted to have successful pregnancy is 2.45cm with high sensitivity (94%), poor specificity (7%).Conclusion: The diameter of cervical cerclage alone is a factor that can poorly predict the success of pregnancy and is negatively correlated to duration of gestational age at time of delivery. This is because of other factors that may affect it s results.