Pregnancy outcomes in women with a prior cervical intraepithelial neoplasia grade 3 diagnosis : a nationwide population-based cohort study with sibling comparison design

Abstract

Background: Treatment of cervical intraepithelial neoplasia grade 3 (CIN3) removes or destroys part of the cervix and might subsequently influence pregnancy outcomes. Objective: To investigate pregnancy outcomes in women diagnosed with CIN3.

Design: Population- and sibling-matched cohort study.

Setting: Sweden, 1973-2018.

Participants: General population comparison included 78 450 singletons born to women diagnosed with CIN3 and 784 500 matched singletons born to women in the general population who had no CIN3 diagnosis; sibling comparison included 23 199 singletons born to women diagnosed with CIN3 and 28 135 singletons born to their sisters without a CIN3 diagnosis.

Measurements: Preterm birth, including spontaneous or iatrogenic preterm birth; Infection-related outcomes, including chorioamnionitis and infant sepsis; and early neonatal death, defined as death during the first week after birth.

Results: Compared with the matched general population, women previously diagnosed with CIN3 were more likely to have a preterm birth especially extremely preterm (22-28 weeks; OR, 3.00; 95% CI, 2.69-3.34) and spontaneous preterm (OR, 2.12; 95% CI, 2.05-2.20) birth, infection-related outcomes including chorioamnionitis (OR, 3.23; 95% CI, 2.89-3.62) and infant sepsis (OR, 1.72; 95% CI, 1.60-1.86), and early neonatal death (OR, 1.83; 95% CI, 1.61-2.09). Sibling comparison analyses rendered largely similar results. Over time the risk difference attenuated for all outcomes and disappeared for early neonatal death.

Limitations: Lack of data on CIN3 treatment and spontaneous abortion.

Conclusion: Prior history of CIN 3 is associated with adverse pregnancy outcomes even after accounting for familial factors. Decreasing risk estimates over time suggest that adverse pregnancy outcomes among women diagnosed with CIN3 may be minimized by improving treatment modalities.