Abstract
BACKGROUND: This study was conducted to examine associations with contraception methods used at last sexual intercourse among US adolescents. STUDY DESIGN: Data consisted of sexually active adolescents (9th-12th grade, weighted n=24,638) from the 1999-2007 Youth Risk Behavior Surveillance System (YRBSS). We performed multinomial multivariable logistic regression analyses with condom users at last sexual intercourse as the reference group. RESULTS: Males who used alcohol, cigarettes, marijuana and cocaine were more likely to use no method/unsure of method (OR=2.4, CI=1.7-3.4) or rely on withdrawal (OR=2.6, CI=1.5-4.3). Females with six or more sexual partners were more likely to rely on withdrawal (OR=2.9, CI=2.1-3.9) or contraception methods that offer no STI protection [i.e., birth control pills: OR=1.9, CI=1.4-2.5; and depot medroxyprogesterone acetate (DMPA, marketed as Depo-Provera): OR=2.6, CI=1.6-4.2]. Earlier age of sexual debut was also associated with nonuse. CONCLUSION: Prevention efforts should focus on at-risk adolescents including substance-using males, females with six or more sexual partners, and those who initiate sexual intercourse at an early age.