Natural history of cervical intraepithelial neoplasia in pregnancy: postpartum histo-pathologic outcome and review of the literature

BACKGROUND: To study the natural history of cervical intraepithelial neoplasia (CIN) during pregnancy and to compare the rates of persistence, progression and regression of CIN by colposcopically guided biopsy (CGB) during pregnancy with outcome in non-pregnant-women. METHODS: A retrospective analysis of all pregnant women diagnosed with CIN at our outpatient clinic between 2005 and 2010 was performed. A CGB for histo-pathological analysis was obtained in all participants and observational management was performed. The histo-pathologic findings of initial and postpartum visits were collected. Rates of persistence, progression and regression of CIN were assessed. Results were compared to a matched control group of non-pregnant women where observational management was performed for at least three months. In addition a review of the literature and pooled analysis of published data was performed. RESULTS: A total of 51 pregnant women with CIN were included into analysis. CIN 1, 2, and 3 was diagnosed by CGB in 33.3, 13.7 and 52.9 % of all pregnant women, respectively. The postpartum histo-pathologic evaluation of the pregnant cohort revealed a significantly higher tendency to spontaneous regression (56.9 versus 31.4 %, p = 0.010) and a considerably, but not significantly higher complete remission rate (41.2 versus 27.5 %, p = 0.144) when compared to the non-pregnant cohort. In addition, we observed a significantly lower CIN persistence rate than in the non-pregnant cohort (39.2 versus 58.8 %, p = 0.048). The progression rate was notably low in the pregnant cohort (3.9 %) and no progression to invasive cancer was observed. CONCLUSIONS: CIN lesions show considerably high spontaneous regression rates postpartum. Once presence of invasive cancer is ruled out definitive treatment can be deferred to the postpartum period.