Pregnancy outcome after laser surgery for cervical intraepithelial neoplasia

Little is published about obstetrical problems after treatment of cervical intraepithelial neoplasia with the C02-laser. The aim of this study was to determine the risk of low birth weight in the subsequent pregnancy after laser conization or vaporization in a follow-up study of women treated for cervical intraepithelial neoplasia (CIN). Methods. Of 319 women treated for CIN with the C02-laser in the Department of Obstetrics and Gynecology, University Hospital of Tromsø, Norway and followed for pregnancy outcome, 87 women had given birth (after 24th week) four to nine years after treatment. Sixty-five women had undergone conization and 22 women had been treated with vaporization. For each delivery, two controls matched for parity, age (+/- 3 years) and place of delivery were identified. The material was analyzed as a matched cohort study.

A strong relationship was found between conization and low birth weight. Mean birth weight after conization was 3185 g vs 3473 g,in the control women (p=0.03). Thirteen (20%) infants from women subject to conization had birth weight less than 2500 g. Relative risk of birth weight<2500 g was 2.2 (1.04-4.5) after conization, for<2000 g and< 1500 g the risk was 3.5 (1.02-12.0) and 10.0 (1.2-85.6), respectively. Four women (6.2%) with normal deliveries prior to conization experienced one or several stillbirths after treatment. No difference in birth weight was observed for women after vaporization compared to their controls.

Excisional surgery on the cervix increases the risk for low birth weight in subsequent pregnancies. Pregnant women with prior conization need careful antenatal care.