Pregnancy after treatment for cervical cancer precursor lesions in a retrospective matched cohort

Abstract

Objective: To determine whether treatments for precancerous cervical lesions were associated with lower pregnancy rates compared to rates in unexposed women and women who had a diagnostic cervical biopsy or colposcopy. Design: Matched, retrospective cohort study. Setting: Kaiser Permanente Northwest (KPNW), an integrated healthcare delivery system in Oregon and Washington. Patients: Women 14 to 53 years old with KPNW enrollment during the period 1998 through 2009. Main Outcome Measure: Pregnancy after exposure or index date. Pregnancy was defined using a validated algorithm and electronic medical records data. Results: We observed 570 pregnancies following cervical treatment in 4,137 women, 1,533 pregnancies following a diagnostic procedure in 13,767 women, and 7,436 pregnancies in a frequency-matched sample of 81,435 women unexposed to treatment or diagnostic procedures. After adjusting for age and contraceptive use, we observed a higher rate of pregnancies in the treatment group compared to unexposed women (hazard ratio (HR) = 1.42, 95% confidence interval (CI): 1.30-1.55), but no difference in pregnancy rates between the treatment and diagnostic procedure groups (HR = 1.03, 95% CI: 0.93-1.13). Conclusions: No adverse effects of cervical procedures on subsequent rates of pregnancy were observed in this cohort with up to twelve years of follow-up time.