Pregnancy outcomes after cold knife conization related to excised cone dimensions. A retrospective cohort study

To analyze the perinatal outcome of pregnancies following cold knife conization and investigate its relationship, if any, with the amount of tissue removed, and to assess risk factors of perinatal complications.

A retrospective cohort study was designed to compare perinatal outcomes between a group of patients who had prior conization operation (study group) and a group of patients who did not have a conization operation (control group).

The preterm delivery rate and preterm premature rupture of membranes (PPROM) rate were significantly higher in the study group as compared with the control group. The mean cone volume was significantly higher in the group of patients who delivered at <37 weeks as compared with the group of patients who delivered at >37 weeks. For the patients who were diagnosed with PPROM, the mean excised volume and height were higher than those of the group of patients who were not diagnosed with PPROM. In cases with preterm delivery the cutoff value of excised cervix tissue volume was measured as 2.27 cm3, and in cases with PPROM the cutoff value of excised cervix tissue volume was measured as 3.99 cm3.

The perinatal complication frequency was higher for the group of patients who had undergone conization procedure. We found that the volume of excised cervix tissue is more important than the height of the excised cervix tissue in regards to the assessment of perinatal complications. Colposcopy and conization procedure must be performed by the same, experienced specialist. During the procedure unnecessary tissue excision must be avoided.