Adverse obstetrical outcomes after treatment of precancerous cervical lesions: a Belgian multicentre study.

Objective: To assess the impact of cervical intraepithelial neoplasia (CIN) treatment on the risk of (spontaneous) preterm delivery (PD) and small for gestational age (SGA) at birth.

Design: A multicentre cohort study.

Setting: Maternity wards of four academic hospitals in Belgium.

Population: Ninety-seven exposed pregnant women (with a CIN treatment history) and 194 nonexposed pregnant women (without a history of CIN treatment).

Methods: A questionnaire and check of obstetrical files included socio-demographic characteristics, risk factors for PD, obstetrical history for all women and characteristics of the CIN treatment for exposed women. Pregnancy outcomes were recorded after delivery. The influence of previous treatment of CIN on pregnancy outcomes, adjusted for confounding variables, was assessed by Cox regression and lifetables (for the outcome gestational age at birth) and by logistic regression (for the outcomes PD and SGA at birth).

Main Outcome Measures: Occurrence of PD and SGA at birth.

Results: Seventy-nine per cent of the women in the database were multiparous; 16.3% of women with a previous excisional treatment spontaneously delivered preterm, compared with 8.1% of unexposed women [odds ratio (OR), 2.19; 95% confidence interval (CI), 0.97-4.99]. When adjusting for confounding factors (ethnicity, HIV status, education, age, smoking and parity), the OR for PD was 2.33 (95% CI, 0.99-5.49). Excisional treatment did not have an impact on SGA at birth (OR, 0.94; 95% CI,0.41-2.15). The depth of the cone was >10 mm in 63.5% of the documented cases. Large cones, more than 10 mm deep, were associated with a significantly increased risk of PD (adjusted OR, 4.55; 95% CI, 1.32-15.65) compared with untreated women, whereas smaller cones (≤ 10 mm) were not significantly associated with PD (OR, 2.77; 95% CI, 0.28-27.59). The associations seen for PD with respect to the cone size did not hold for SGA at birth.

Conclusions: There was an increased risk of (spontaneous) PD after excision of CIN, in particular when the cone depth exceeded 10 mm.