BackgroundDysplasia may progress because of a loss to follow-up after an abnormal cervical cytology. Approximately 18% of Danish women postpone the recommended follow-up, which depends on the cytology results.AimTo investigate if a reminder to the GP about missed follow-up could reduce the proportion of women who fail to act on a recommended follow-up, and to analyse the effect on sociodemographic and general practice variations.Design and settingA national electronic GP reminder system was launched in Denmark in 2012 to target missed follow-up after screening, opportunistic testing, or surveillance indication. The authors compared follow-up proportions in a national observational before–after study.MethodFrom national registries, 1.5 million cervical cytologies (from 2009 to 2013) were eligible for inclusion. Approximately 10% had a recommendation for follow-up. The proportion of cervical cytologies without follow-up was calculated at different time points. Results were stratified by follow-up recommendations and sociodemographic characteristics, and changes in practice variation for follow-up were analysed.ResultsFewer women with a recommendation for follow-up missed follow-up 6 months after a GP reminder. Follow-up improved in all investigated sociodemographic groups (age, ethnicity, education, and cohabitation status). Interaction was found for age and cohabitation status. Variation between practices in loss to follow-up was significantly reduced.ConclusionAn electronic GP reminder system showed potential to improve the quality of cervical cancer screening through reduced loss to follow-up.