School-based sexual and reproductive health programmes are widely accepted as an approach to reducing high-risk sexual behaviour among adolescents. Many studies and systematic reviews have concentrated on measuring effects on knowledge or self-reported behaviour rather than biological outcomes, such as pregnancy or prevalence of sexually transmitted infections (STIs).

To evaluate the effects of school-based sexual and reproductive health programmes on sexually transmitted infections (such as HIV, herpes simplex virus, and syphilis), and pregnancy among adolescents.

We searched MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) for published peer-reviewed journal articles; and ClinicalTrials.gov and the World Health Organization's (WHO) International Clinical Trials Registry Platform for prospective trials; AIDS Educaton and Global Information System (AEGIS) and National Library of Medicine (NLM) gateway for conference presentations; and the Centers for Disease Control and Prevention (CDC), UNAIDS, the WHO and the National Health Service (NHS) centre for Reviews and Dissemination (CRD) websites from 1990 to 7 April 2016. We handsearched the reference lists of all relevant papers.

We included randomized controlled trials (RCTs), both individually randomized and cluster-randomized, that evaluated school-based programmes aimed at improving the sexual and reproductive health of adolescents.

Two review authors independently assessed trials for inclusion, evaluated risk of bias, and extracted data. When appropriate, we obtained summary measures of treatment effect through a random-effects meta-analysis and we reported them using risk ratios (RR) with 95% confidence intervals (CIs). We assessed the certainty of the evidence using the GRADE approach.

We included eight cluster-RCTs that enrolled 55,157 participants. Five trials were conducted in sub-Saharan Africa (Malawi, South Africa, Tanzania, Zimbabwe, and Kenya), one in Latin America (Chile), and two in Europe (England and Scotland).

Sexual and reproductive health educational programmes

Six trials evaluated school-based educational interventions.

In these trials, the educational programmes evaluated had no demonstrable effect on the prevalence of HIV (RR 1.03, 95% CI 0.80 to 1.32, three trials; 14,163 participants; low certainty evidence), or other STIs (herpes simplex virus prevalence: RR 1.04, 95% CI 0.94 to 1.15; three trials, 17,445 participants; moderate certainty evidence; syphilis prevalence: RR 0.81, 95% CI 0.47 to 1.39; one trial, 6977 participants; low certainty evidence). There was also no apparent effect on the number of young women who were pregnant at the end of the trial (RR 0.99, 95% CI 0.84 to 1.16; three trials, 8280 participants; moderate certainty evidence).

Material or monetary incentive-based programmes to promote school attendance

Two trials evaluated incentive-based programmes to promote school attendance.

In these two trials, the incentives used had no demonstrable effect on HIV prevalence (RR 1.23, 95% CI 0.51 to 2.96; two trials, 3805 participants; low certainty evidence). Compared to controls, the prevalence of herpes simplex virus infection was lower in young women receiving a monthly cash incentive to stay in school (RR 0.30, 95% CI 0.11 to 0.85), but not in young people given free school uniforms (Data not pooled, two trials, 7229 participants; very low certainty evidence). One trial evaluated the effects on syphilis and the prevalence was too low to detect or exclude effects confidently (RR 0.41, 95% CI 0.05 to 3.27; one trial, 1291 participants; very low certainty evidence). However, the number of young women who were pregnant at the end of the trial was lower among those who received incentives (RR 0.76, 95% CI 0.58 to 0.99; two trials, 4200 participants; low certainty evidence).

Combined educational and incentive-based programmes

The single trial that evaluated free school uniforms also included a trial arm in which participants received both uniforms and a programme of sexual and reproductive education. In this trial arm herpes simplex virus infection was reduced (RR 0.82, 95% CI 0.68 to 0.99; one trial, 5899 participants; low certainty evidence), predominantly in young women, but no effect was detected for HIV or pregnancy (low certainty evidence).

There is a continued need to provide health services to adolescents that include contraceptive choices and condoms and that involve them in the design of services. Schools may be a good place in which to provide these services. There is little evidence that educational curriculum-based programmes alone are effective in improving sexual and reproductive health outcomes for adolescents. Incentive-based interventions that focus on keeping young people in secondary school may reduce adolescent pregnancy but further trials are needed to confirm this.

Cochrane researchers conducted a review of the effects of school-based interventions for reducing HIV, sexually transmitted infections (STIs), and pregnancy in adolescents. After searching for relevant trials up to 7 April 2016, they included eight trials that had enrolled 55,157 adolescents.

Why is this important and how might school-based programmes work?

Sexually active adolescents, particularly young women, are at high risk in many countries of contracting HIV and other STIs. Early unintended pregnancy can also have a detrimental impact on young people's lives.

The school environment plays an important role in the development of children and young people, and curriculum-based sexuality education programmes have become popular in many regions of the world. While there is some evidence that these programmes improve knowledge and reduce self-reported risk taking, this review evaluated whether they have any impact on the number of young people that contracted STIs or on the number of adolescent pregnancies.

What the research says

Sexual and reproductive health education programmes

As they are currently configured, educational programmes alone probably have no effect on the number of young people infected with HIV during adolescence (low certainty evidence). They also probably have no effect on the number of young people infected with other STIs (herpes simplex virus: moderate certainty evidence; syphilis: low certainty evidence), or the number of adolescent pregnancies (moderate certainty evidence).

Material or monetary incentive-based programmes to promote school attendance

Giving monthly cash, or free school uniforms, to encourage students to stay in school may have no effect on the number of young people infected with HIV during adolescence (low certainty evidence). We do not currently know whether monthly cash or free school uniforms will reduce the number of young people infected with other STIs (very low certainty evidence). However, incentives to promote school attendance may reduce the number of adolescent pregnancies (low certainty evidence).

Combined educational and incentive-based programmes

Based on a single included trial, giving an incentive such as a free school uniform combined with a programme of sexual and reproductive health education may reduce STIs (herpes simplex virus; low certainty evidence) in young women, but no effect was detected for HIV or pregnancy (low certainty evidence).

Authors' conclusions

There is currently little evidence that educational programmes alone are effective at reducing STIs or adolescent pregnancy. Incentive-based interventions that focus on keeping young people, especially girls, in secondary school may reduce adolescent pregnancy but further high quality trials are needed to confirm this.