Obstetric outcomes after loop electrosurgical excision procedure for cervical intraepithelial neoplasia: a single-centre retrospective cohort study of excision dimensions

Abstract Background Loop electrosurgical excision procedure (LEEP) is the standard treatment for high-grade cervical intraepithelial neoplasia (CIN) and is performed predominantly in women of reproductive age. Data on subsequent pregnancy outcomes from Turkish cohorts are limited. We described obstetric outcomes after LEEP and examined whether excision dimensions — depth, diameters and calculated cone volume — were associated with preterm birth and spontaneous miscarriage. Methods Single-centre retrospective cohort study at a tertiary gynaecological oncology referral centre. Forty women who conceived after LEEP for CIN were identified; each contributed one pregnancy. One elective termination of pregnancy was excluded because it is not an obstetric outcome, leaving 39 pregnancies for analysis. Cone volume was calculated from pathology-reported specimen dimensions using the hemi-ellipsoid formula. Group comparisons used the Mann–Whitney U and Fisher exact tests. Because outcome events were few (eight preterm births, seven miscarriages), regression models were restricted to a single predictor and fitted with Firth penalized likelihood; two-predictor models are reported only as sensitivity analyses. There was no concurrent untreated comparison group, so no causal effect of LEEP can be estimated. Results Of 39 pregnancies, 31 (79.5%) ended in live birth, seven (17.9%, 95% CI 7.5–33.5) in spontaneous miscarriage before 20 weeks and one (2.6%) in stillbirth at 36 weeks. Among live births, preterm birth before 37 weeks occurred in 8/31 (25.8%, 95% CI 11.9–44.6) and before 34 weeks in 2/31 (6.5%). There were no cases of PPROM or clinically diagnosed cervical insufficiency. Cone depth was greater in preterm than in term deliveries (median 32.5 vs. 23.0 mm; p = 0.004) and was associated with preterm birth in penalized regression (odds ratio [OR] 1.19 per mm, 95% CI 1.05–1.41; p = 0.006); a depth of 30 mm or more carried an OR of 9.20 (95% CI 1.70–61.09; p = 0.010). Cone depth was also associated with miscarriage (OR 1.13 per mm, 95% CI 1.02–1.27; p = 0.025), although this attenuated to OR 1.07 ( p = 0.23) once maternal age was included. Maternal age was the strongest correlate of miscarriage (OR 1.37 per year, 95% CI 1.10–1.87; p = 0.004). Calculated cone volume was strongly collinear with depth (Spearman ρ = 0.84) and showed a weaker association with preterm birth (OR 1.29 per cm³, 95% CI 1.02–1.71; p = 0.035). The LEEP-to-conception interval was not associated with either outcome. Conclusions In this small cohort, greater cone depth was associated with both preterm birth and spontaneous miscarriage, and maternal age was the dominant correlate of miscarriage. Calculated cone volume was strongly collinear with depth and did not improve prediction. Half of the preterm births were medically indicated, and the depth association did not persist when analysis was restricted to spontaneous preterm birth. Event counts were low and confidence intervals were wide, so these findings are exploratory and hypothesis-generating rather than confirmatory. They are consistent with existing evidence supporting excision of the minimum adequate cone depth.