Do Norwegian providers comply with national recommendations when prescribing combined oral contraceptives to starters? A cohort study

Objectives To assess whether changes in patterns of combined oral contraceptive (COC) prescriptions to starters between 2008 and 2016 were in line with changes in national recommendations for use. Design Historical prospective cohort study. Setting The national Norwegian Prescription Database. Participants Women aged 10-49 years who started COCs between 1 January 2008 and 30 June 2016, in total 285 009 women. Primary outcome The proportion of levonorgestrel-containing COC prescriptions to starters. Intervention The Norwegian Medical Agency recommended levonorgestrel-containing COCs to starters from 2010 onwards. Results The proportion of levonorgestrel-containing COCs prescribed to starters increased from 41% in 2008 to 80% in 2016 with the greatest increase from 2011 to 2012. This prescription pattern comprised all age groups but was observed to a lower extent among older women. Public health nurses and midwifes had the highest compliance with recommendations and prescribed levonorgestrel-containing COCs to 96% of starters aged <20 years in 2016, compared with 75% and 86% among general practitioners and doctors with no specialty. Conclusion All professions have increased the proportion of levonorgestrel-containing COC prescriptions to starters. Public health nurses and midwives had the highest compliance with the new recommendations. Future studies will examine whether this shift in prescription pattern has prevented venous thromboembolism in women of reproductive age in Norway.