Natural history of cervical intraepithelial neoplasia during pregnancy.

Objective: It is uncertain whether pregnancy influences the natural history of cervical intraepithelial neoplasia (CIN). Our aim was to evaluate the evolution of CIN in pregnant women.

Design: Prospective study.

Setting: Department of Obstetrics and Gynaecology, University of Insubria, Italy.

Population: Women with histological CIN during pregnancy.

Methods And Main Outcome Measures: Between 2003 and 2007, women with an abnormal Pap-smear during pregnancy underwent colposcopy. Patients with histological CIN were followed during pregnancy with colposcopy every 8 weeks and post-partum evaluation was scheduled 3-6 months after delivery. Women with post-partum histological diagnosis of CIN 2-3 underwent conization. To understand the impact of pregnancy on the evolution of CIN, women with CIN 1 discovered during pregnancy were compared to a group of non-pregnant fertile patients with first diagnosis of CIN 1.

Results: A total of 78 women were included: 36 (46.2%) with CIN 2-3 and 42 (53.8%) with CIN 1. In women with CIN 2-3, no invasion was suspected during pregnancy and at post-partum evaluation, no invasive or microinvasive cancer, and 19 (52.7%) persistent CIN 2-3, and 17 (47.3%) regressions were diagnosed. In the group of CIN 1, we recorded six (14.3%) progressions to CIN 2-3, seven (16.6%) persistent CIN 1 and 29 (69%) regressions. The control group of non-pregnant women had a lower regression rate (37/76: 48.7%) in comparison to pregnant women (p=0.03).

Conclusions: Expectant management for CIN 2-3 diagnosed during gestation is safe. When discovered during pregnancy, CIN 1 has a significantly higher tendency to spontaneous regression in comparison to non-pregnant condition.