23. Association of LARC Uptake with Method Continuation

Junior enlisted servicewomen in the United States (US) military have a higher rate of unintentional pregnancies than the general population, despite availability of no-cost contraception. The Navy implemented the “LARC Forward” program in January 2015 to improve access to contraception during basic training. This program increased contraceptive use among women in the Navy and doubled use of long-acting reversible contraceptive (LARC) methods (11.0% to 22.7%) at 6-months on active-duty but did not decrease 24-month fertility rates. It is unclear why the LARC Forward program increased contraception use but did not decrease fertility. This study further explores the association of the LARC Forward program with subsequent childbirth by examining LARC continuation and contraception use during the first 4-years on active-duty among women exposed to the LARC Forward program. This study is a secondary analysis of insurance billing data from women who enlisted in the Navy or Army between 9/1/2012 and 2/8/2020. We used Current Procedural Terminology Codes and pharmacy records to identify the type and timing of any contraceptive use. We used bivariable Kaplan-Meier and multivariable Cox Proportional Hazards analyses to assess the hazard of premature LARC discontinuation. We used binomial regression for interval censored data, specifying complimentary log-log as the link function, to assess the bivariable and multivariable associations of our predictor variables with days on contraception and days using a LARC method during the first 4 years on active duty. We assessed the bivariable relationship of age-group, service branch, and training before or after LARC Forward implementation (1/1/2015) with our study outcomes. Our multivariable analyses included age-group as a covariate and examined the effects of service branch, training before or after LARC Forward, and the interaction between these variables. This research was IRB approved and conducted using SPSS 28.0. We included 90414 women in our study. The average age was 20.4+/-3.1 years, 66% of the sample was 18-20 years old, and 50.1% were in the Army. The 3-year implant continuation rate was 25.1% (95%CI 24.3, 25.9). The 4-year intrauterine device continuation rate was 27.8% (26.4, 29.2). Overall, servicewomen were using prescribed contraception during 32.2% of their 4-year enlistment period and specifically a LARC method during 16.4% of that time. In multivariable analyses, women in the Navy had higher rates of LARC continuation, contraceptive use, and LARC use than women in the Army. Women who joined the Army after January 2015 experienced a decline in overall contraceptive use (26.3% to 22.5%) and LARC use (10.9% to 10.4%), while women who joined the Navy after implementation of LARC First experienced an increase in overall contraception (36.8% to 39.6%) and LARC (16.6% to 24.4%) use. (Time X Service Interactions: Overall Contraceptive Use β=0.270 (95%CI 0.268-0.271) and LARC Use β=0.483 (95%CI 0.481-0.485)). This increase in LARC use was not associated with a decline in LARC continuation. A group intervention to improve contraception education and access for young adult women with access to no cost contraception was associated with increased contraceptive and LARC use without decreasing LARC continuation rates.