Having just posted on systematic reviews, let’s take a look at some recent examples on a topic of importance in contemporary society: sexual activity and pregnancy on the part of teenagers. We tend to throw up our hands about this problem, but systematic evidence-based reviews show that some intervention programs actually work, and others don’t. Take a look at these as examples of how systematic reviews work and what they can tell us.
A Cochrane Collaboration review team examined the literature on teen pregnancy prevention. They examined studies of primary pregnancy prevention carried out in a variety of settings. Findings from a total of 41 randomized, controlled trials were synthesized. The review team found that programs that combined educational and contraceptive interventions were effective in preventing teen pregnancy.
A systematic review was conducted of programs to promote condom use among teens. This study is a good example of a review that concluded there was insufficient evidence to be definitive. Although many individual intervention studies showed modest effects, the authors noted that the quality of most of the studies was poor. So in this case, we really can’t be sure interventions to promote condom use really work.
What about abstinence? Our friendly neighborhood Cochrane reviewers have taken this on, too. They conducted a systematic review of abstinence-only HIV prevention programs, and found no evidence that such programs protected against sexually transmitted diseases. They also did not prevent teens from engaging in unprotected intercourse, the frequency of intercourse, the number of sexual partners, age of sexual initiation, or condom use.