Adherence to no-cost oral contraceptives among active-duty servicewomen

Background We aimed to evaluate the adherence to no-cost oral contraceptives (OC) among young single women and to identify factors associated with non-adherence. Methods Retrospective cohort study included all single female soldiers who received free-of-charge OCs from military pharmacies in Israel between 2006 and 2015. Military pharmacies' dispensing registries were queried to assess the number of OC packages dispensed. Women were included in the study if their service continued for a period of at least 12 months from the time of receiving their first OC pack. Study outcomes were twelve cycles medication possession ratio (MPR), which is defined as the number of OC packs dispensed over a 12-cycle period divided by 12, presented as a percentage, and factors associated with the OC MPR as evaluated by multivariable regression analysis. Results During the study period, there were 3 05 923 active servicewomen aged 18-24 years. A total of 82 203 (26.9%) women were dispensed at least one pack of OCs. The mean MPR was 51.8% (35.2%). Only 14% of women had good adherence (MPR ≥90%). Multivariate regression models showed that non-adherence (MPR <90%) was more common among servicewomen (adjusted OR (95% CI)): who failed to graduate from high school (1.9 (1.54-2.33)) and with combat or combat-support type of service (1.66 (1.30-2.13)). Other social/ethnic factors, including first-generation immigrant (1.13 (1.05-1.21)), sub-Saharan African origin (1.28 (1.04-1.58)), lower IQ scores (1.28 (1.22-1.34)) and combat-support type of service (1.22 (1.12-1.34)) were associated with non-adherence, but to smaller degrees. Neither income nor health status predicted adherence in this population receiving no-cost OCs. Conclusions Overall, 12 cycles OC adherence was universally low among active servicewomen. Adherence demonstrated small, but significant, associations with sociodemographic factors, with the lowest levels of adherence predicted by low educational attainment and combat service.