High-Risk Sexual Behavior and Reproductive Health in Adolescents and Young Adults in Europe and the Americas: A Systematic Review of Prevention Programs

Background/Objectives: Adolescents and young adults are more likely to adopt high-risk sexual behavior that may lead to Sexually Transmitted Infections (STIs), unintended pregnancies, and persistent reproductive health impacts. This study aimed to summarize prevention interventions targeting high-risk sexual behavior among adolescents (10–18 years) and young adults (19–24 years) in Europe and the Americas, and to explore their effects across knowledge, attitudes, sexual behavior, and reported sexual and reproductive health or health-service indicators. Methods: This systematic review was conducted in line with the PRISMA 2020 guidelines. The literature search was carried out in PubMed, Scopus, and the Cochrane Library for studies published between 2017 and 2025. Results: According to the inclusion criteria 31 studies were included in the study. Most interventions were delivered mainly in school-based and community-based settings and targeted mainly adolescents. Notably, a limited number of interventions were delivered specifically to young adults, indicating a remarkable gap in prevention focus to this age group. Most studies revealed reported positive results for knowledge acquisition, attitudes, decision-making skills, contraception use, prevention STIs, negotiation skills with sexual partners, and prevention of unintended pregnancies. Evidence for robust health indicators was comparatively limited, and sustainability of effects was not systematically assessed. Conclusions: This review suggests that prevention programs aiming to reduce high-risk sexual behavior of young people demonstrate overall effectiveness in improving sexual and reproductive health outcomes among adolescents. Nevertheless, few interventions are addressed to young adults highlighting the need for age-specific, developmentally appropriate programs.