Adverse obstetrical outcomes associated with treatment of dysplastic lesions of the cervix in a universally funded, single payor health care system

Objective — To investigate the relationship between adverse obstetrical outcomes and cervical dysplasia treatments.

Methods — This study used linked health care databases through the Institute of Clinical Evaluative Sciences, in Ontario Canada, between 2005-2019. We conducted a population-based retrospective cohort study of pregnant women who had undergone previous colposcopy and subsequently had a pregnancy, comparing the no treatment cohort to patients who had a cervical excisional procedures (CEP) or cervical ablative procedures (CAP). The primary outcome was preterm birth (PTB). The secondary outcomes included preterm premature rupture of membranes, low birthweight, spontaneous abortion, stillbirth, and cervical incompetence. Cox proportional hazard models were used to calculate hazard ratios. We used unadjusted logistic regression to compare outcomes between those who underwent CEP vs CAP. Odds ratios with 95% confidence intervals were calculated.

Results — We included 515 726 pregnant patients. After exclusion criteria, 109 930 patients remained. There were 74 291 patients in the control group, 24 133 patients in the CEP group and 11 506 patients in the CAP group. In the control group 2620 patients (5.7%) had a PTB versus 1321 (7.6%) and 592 (6.5%) in the CEP and CAP groups, respectively (OR 1.18 95% CI 1.07-1.31, P<0.01). After controlling for age, there was a 32% increased risk of PTB with a CEP (HR 1.32, 95% CI 1.24-1.40, P<0.001). For a CAP, there was no increased risk in PTB (HR 1.01, 95% CI 0.94-1.09, P = 0.74.

Conclusion — In this large Ontario dataset of pregnant patients who underwent previous colposcopy, CEP was associated with PTB.