Association of intrauterine device use and risk of abnormal cervical cytology

To determine whether intrauterine device (IUD) use is associated with a significantly increased risk of abnormal cervical cytology.

A retrospective cohort study was carried out at the University of Campinas, Campinas, SP, Brazil. Data came from medical records of 2,963 women from a family planning clinic who had undergone at least one cervical cytology for screening between 1990 and 2017. Women were split into three groups: users of either copper (Cu)- or the levonorgestrel 52 mg-IUD (2,305) and users of other contraceptive methods (658). The dependent variable was the cytological results as normal and abnormal, based on the Bethesda System. The most severe cytological result of each participant was considered and when all her results were normal, the last one was considered.

IUD use was associated with a lower risk of abnormal cervical cytology after adjusting for the number of cytology assessments per participant (RR 0.74; 95% CI 0.55;0.99; p = 0.049). Abnormal cervical cytology was more common in women with multiple cytology assessments and a longer duration since sexual debut. For each additional cytology test, the risk increased by 33.8% (p < 0.001), and for every additional year since sexual debut, the risk increased by 6.2% (p < 0.001). A lower incidence of abnormal cervical cytology was observed among women with a history of caesarean delivery, with a 24.9% reduction in risk per additional caesarean (p < 0.001). IUD users underwent more cervical cytology assessments than non-IUD users.

We identified low risk of abnormal cervical cytology among IUD users.