Contraceptive use and childbirth rates by service branch during the first 24 months on active duty in the United States military from 2013 to 2018: a retrospective cohort analysis

Objective: To measure the association of military branch-specific contraceptive education and access policy during basic training with contraceptive use and childbirth among new recruits. Study design: Secondary analysis of insurance records from 92,072 active duty servicewomen who started basic training between 2013 and 2017. Results: Exposure to reproductive health education and access to contraception during basic training differ by military branch. Highly effective contraception use (pills, patch, ring, shot, implants or intrauterine contraception) at 6 months on active duty [Army (18.1%), Air Force (27.4%), Marines (26.5%) and Navy (37.6%), p<.001], long-acting reversible contraceptive method use (implant or intrauterine) at 6 months [Army (2.0%), Air Force (3.7%), Marines (11.0%) and Navy (19.6%), p<.001] and childbirth in the first 24 months of service [Army (11.1%, 95% CI 10.7–11.5), Air Force (6.0%, 95% CI 5.6–6.4), Marines (8.4%, 95% CI 7.8–9.0) and Navy (6.7%, 95% CI 6.3–7.1)] varied by service branch. After adjusting for age at basic training and contraceptive use at 6 months on active duty, childbirth rates differed among all branches. The Army (hazard ratio 1.86, 95% CI 1.71–2.01), Marines (1.48, 95% CI 1.33–1.65) and Navy (1.24, 95% CI 1.13–1.35) all had a higher risk of delivery than the Air Force. Conclusion: Variation in branch-specific contraceptive education and access policy during basic training is associated with differences in rates of contraceptive use at 6 months on active duty and childbirth prior to 24 months on active duty. This occurs despite all recruits having access to an identical medical benefit including no-cost access to contraception after completing initial training. Further study is needed to determine the etiology of these differences. Implications: Guidelines for contraceptive education and access during basic training, highly effective contraception use after 6 months of service and childbirth in the first 24 months of service vary among branches of the United States military. Reducing this variability may reduce childbirth rates and improve the reproductive health of junior enlisted servicewomen.