Cervical excisional treatment, HPV infection and risk of preterm delivery - a Swedish population-based study

Objective\ua0Excisional treatment for cervical intraepithelial neoplasia (CIN) is associated with preterm delivery (PTD). It has been shown that even untreated CIN is associated with PTD. We aimed to explore the magnitude of the associations of CIN with PTD and adverse obstetrical outcome.Methods\ua0Retrospective register-based study comprising all women with singleton deliveries in Sweden 1999-2016. Data were retrieved from the Medical Birth Registry and the Swedish National Cervical Screening Registry. Women with normal cytology all life (n = 340,290) were compared to a) women with sign of HPV-infection close to pregnancy (abnormal cytology (n = 11,936) or positive HPV-test (n = 2,587)), b) women treated for CIN before delivery (n = 25,123) and c) women with CIN/carcinoma diagnosed after delivery (n = 34,251) by logistic regression adjusted for socioeconomic and health-related confounders.Results\ua0PTD was increased in all groups compared to women with normal cytology all life (4.7 %), with greatest risk for the treated group (9,0 %, OR 1.80 (1.71-1.89)), but also for women with HPV-infection close to pregnancy (5,9 %, OR 1.19 (1.10-1.29)) and CIN/carcinoma after delivery (6,1 %, OR 1.10 (1.04-1.16)). Paired analysis in 5,547 women with deliveries both before and after treatment showed increased risk of PTD after treatment (OR 1.27 (1.07-1.50)). The treated group had increased risk also for preterm prelabour rupture of the membranes (pPROM, OR 2.25 (2.08-2.44)) and chorioamnionitis (2.44 (2.05-2.90)). HPV-infection close to pregnancy was associated with pPROM (OR 1.22 (1.06-1.40)).Conclusions\ua0Women with HPV infection close to pregnancy have a small increased risk for PTD and pPROM while excisional treatment increases risks further