Use of prescribed contraception in Northern Ireland 2010-2016

Objective: To describe the use of prescribed contraceptives in Northern Ireland (NI) and explore how this varies according to a woman’s age, the deprivation in the area in which she lives and characteristics of her General Practice (GP). Design & Methods: A population-based cohort study was conducted including 560,074 females aged 12-49 registered with a General Practitioner in NI 2010-2016 contributing 3,255,500 woman-years. Dispensed contraceptive prescriptions, recorded in the Enhanced Prescribing Database, were linked to demographic details in the GP Patient Registrations Index and the area-based NI Multiple Deprivation Measure 2017. Results: A contraceptive prescription was redeemed in 26.2% of woman-years. Those aged 20-24 were most likely (45.7% of woman-years) to have a contraceptive prescribed and those less than 16 least likely (6.8% of woman-years). Practices in the least deprived quintile prescribed 6% more contraception than those in the most deprived quintile. The combined oral contraceptives (CoC) (16.6% of woman-years) and progesterone only pill (PoP) (8.0% of woman-years) were the most commonly used methods with a 12% decrease in dispensation of the CoC in favour of a 23% increase in the PoP during the study period. Dispensation of emergency contraception (1.5% of woman-years) also fell by 5%. Women living in the least deprived areas used 20% less emergency contraception and rural GP practices prescribed 7% less. Choice of long-acting reversible contraception (LARC, overall 2.6% of woman-years) varied with age with younger women most likely to use the contraceptive injection (20-24) and contraceptive implant (25-29) and older women (30-35) the IUD/S. Use of the injection decreased 6% during the study while use of the implant increased 12% and IUD/S increased 6%. Practice size and location impacted on choice of LARC with the smallest practices (0-2,500 patients) dispensing 11% more of the contraceptive injection and 24% less of the IUD/S than practices with 7,001-10,000 patients. Rural practices dispensed 15-20% more implants and IUD/S than urban practices. Practices in the least deprived areas dispensed the implant 19% less. Conclusions: This is the first population-based assessment of contraceptive prescription in NI and will be useful for future comparisons and health service planning. Patient and practice level characteristics were found to be related to the specific contraceptive methods prescribed which also changed during the time frame of the study. The impact of practice area-based deprivation, above that of the woman’s residence, on prescribed contraceptive use is a new finding that deserves more exploration.