Thirty papers that evaluated 26 sexual health projects were included; there may have been overlap between papers in the projects evaluated. There were six controlled before-and-after studies (classed as higher-quality studies). The other studies were classed as lower-quality study designs.
Impact on rates of sexual activity: Nine studies reported recent sexual activity rates. Evidence from six better-quality studies and one poorer-quality study suggested that provision of school-based and school-linked sexual health services was not associated with an increase in sexual activity or (based on one better-quality study) a lowering of the age of first sexual intercourse. Based on one better-quality study there may have been a reduction in the proportion of students who reported high numbers of sexual partners.
Use of services by sexually active students: Data were available from nine studies on this outcome. There was wide variation in use of school-based condom availability schemes. Uptake was higher when condoms were available free of charge from baskets than from paid vending machines. Evidence on school-based health centres was limited to males who obtained condoms and females who obtained oral contraceptives, but not use of the wider range of sexual health services. Use of services to obtain contraception tended to be higher where contraceptives were provided on-site than where vouchers were provided to be redeemed elsewhere.
Contraceptive use: Data were available from 15 studies on this outcome. There was no good-quality evidence of a consistent association between increased contraceptive use and availability of sexual health services in school-based or school-linked clinics or health centres. There was no good-quality evidence of an statistically significant association between condom availability schemes and increased condom use.
Pregnancy: Seventeen studies reported data on this outcome. There was no high-quality evidence on the impact on the number of unwanted conceptions. There was evidence from one better-quality study of a reduction in live births to teenage mothers.
Sexually transmitted infections: Five studies reported this outcome. Evidence from a single poorer-quality study suggested that school-based screening and treatment for chlamydia and gonorrhoea may have been associated with reduced prevalence of chlamydia in males.