Cervical Conization and the Risk of Preterm Birth: A Population-Based Multicentric Trial of Turkish Cohort.

INTRODUCTION: Cold Knife Conization (CKC) is one of the most effective methods for the treatment of Cervical Intraepithelial Neoplasia (CIN). Some studies showed a relation between preterm birth and the treatment of CIN; on the other hand, other studies do not show such a relationship.

AIM: The present study was conducted with the aim to investigate the pregnancy outcomes of Turkish women regarding demographic characteristics, obstetric history, removed tissue, and residual cervical length after CKC and to determine the effect of removed cervical tissue volume and height on preterm birth.

MATERIALS AND METHODS: This study was a population-based, multicenter trial that was conducted on singleton pregnancies between January 2007 and December 2013. The control group comprised of 38,892 patients who gave birth during this period. On the other hand, patients who conceived after CKC during this period were invited to the hospital and included in the case group (n=20). The course of pregnancy following CKC was studied. Preterm birth rates, risk factors for preterm birth, conisation age, cervical smear and colposcopic biopsy results and the volume and height of the removed cervical tissue of those patients were evaluated.

RESULTS: There was no statistically significant difference in preterm birth rates between the case and the control groups. None of our cases had any identified preterm birth risk factor except for one case. The average height of removed cervical tissue was 12.6±5.4 mm and the average length of the residual cervix after birth was 28.7±4.3 mm.

CONCLUSION: Removal of cervical tissue of 12.6±5.4 mm in height and 2.35±2.27 cm(3) in volume will not increase the risk of preterm birth of women who do not have any other preterm birth risk factors. If there is no other preterm birth risk factors, term birth is most probably possible after conisation.