WASHINGTON (FRONTLINE MEDICAL NEWS) – While use of long-acting reversible contraception (LARC) has steadily been increasing over recent years, a new study shows that adolescent females who use LARC might be neglecting to wear condoms when engaging in sexual intercourse, regardless of their number of partners, thus predisposing them to a high risk of contracting sexually transmitted infections (STIs).

“Like moderately effective methods of contraception, [LARC] does not protect against STIs, and so use of a condom in conjunction with [LARC] is recommended for STI prevention,” lead author Riley J. Steiner of the Centers for Disease Control and Prevention in Atlanta, explained at the annual meeting of the Society for Adolescent Health and Medicine. The study also was published in JAMA Pediatrics ( 2016 Mar 14. doi:10.1001/jamapediatrics.2016.0007 )

She added that, “We really think that establishing a link between LARC and condom use early on, prior to widespread adolescent uptake of LARC, can help provide a useful reference point for future monitoring and, ultimately, inform STI prevention efforts as LARC is brought to scale.”

Ms. Steiner and her coinvestigators used data from the 2013 national Youth Risk Behavior Survey , a self-administered “paper and pencil” questionnaire conducted every 2 years for students in grades 9-12 in public and private high schools across the United States. Analysis of the data – which looked for age, race, and type of contraceptive used – was conducted in July and August of 2015.

Primary outcome of the analysis was to determine the contraceptive method used the most recent time a female had sexual intercourse: either LARC – via an intrauterine device or an implant – oral contraceptives, Depo-Provera, a patch, or a ring. In total, 2,288 females were included in the study; 41% used condoms, 22% used oral contraceptives, 16% used no contraceptive methods whatsoever, 12% used “withdrawal or other method,” 6% used either Depo-Provera, a patch, or a ring, 2% said they were unsure of what contraceptive, if any, they used, and only 2% of females used LARC.

However, of the 2% that used LARC, adjusted odds ratios revealed that they were significantly more likely not to use condoms (adjusted prevalence ratio [aPR], 0.42; 95% confidence interval, 0.21-0.84) as opposed to females on oral contraceptives. There was no significant difference found in condom use between females on LARC versus those on Depo-Provera, a patch, or a ring (aPR = 0.57; 95% CI, 0.26-1.25).

“Health care professionals may be more likely to offer LARC to adolescents who report not using condoms or using them infrequently, as LARC methods are particularly well suited for adolescents who have difficulty adhering to coitally dependent methods,” Ms. Steiner and her associates said, adding that it is currently unknown “whether the association varies by partnership type; it is possible that the observed differences occur largely among adolescents who consider themselves to be in committed partnerships and thus are less concerned about STIs.”

Females included in the study were 57% white, with just over a third of all 2,288 subjects being in the 12th grade. Condom use was most prevalent among 9th graders (47%), while non-Hispanic blacks and Hispanic females tended to use condoms the most (47% and 46%, respectively). LARC use, though low overall, was highest among 12th graders (3%) and non-Hispanic whites (2%).

The study was funded partly by grants from the National Institute of Allergy and Infectious Diseases, and the Centers for Disease Control and Prevention. Ms. Steiner did not report any relevant financial disclosures.