Teenage pregnancy rates in the UK are among the highest in Western Europe and rising. For older teenagers, pregnancy can be a positive experience, but there is an undeniably strong negative association among very young women between the age of conception and subsequent adverse health and social outcomes for mother and child alike. 

So what can prevention science contribute to this most irrecusable of risks? Not enough, if a systematic review conducted in 2006 by the Campbell Collaboration is the measure. It highlighted a dearth of robust evidence about what works in preventing pregnancy in the vulnerable early teenage years. 

For example, the handful of rigorous evaluations of abstinence-focused sex education programs that promulgate a “no sex until marriage” message without offering any information about contraception showed, at best, no effect.

At worst, exposure to a type of intervention increasingly in popularity in the US, was followed by a small increase in teen pregnancy rates. 

Sex education programs that included a contraception component varied appreciably in their effectiveness. No evidence was found for the value of one-off consultations between teenagers and health professionals.

The most promising avenue identified in the Campbell review was the one taken by intensive “multi-component” youth development programs. They target the manifold risks and social disadvantages associated with teenage pregnancy, such as sexual behavior, substance abuse, and economic hardship, and offer information on contraception and a range of positive school or community engagement activities. [See for example, The Carrera Program] 

But even here the supporting evidence is scarce and there is a great deal of variation in their effectiveness. Why so? [See: Pregnancy prevention trial falls flat]

An investigation by Angela Harden and Ann Oakley reported in the British Medical Journal is illuminating, and noteworthy for a high quality systematic review of the experimental evidence, and for marrying its findings with robust qualitative studies to establish how programs may be aligned with young people’s expressed needs. 

Harden and Oakley’s study confirms the Campbell finding that a handful of multi-component interventions work. They estimate that pregnancy rates are almost 40% lower for the young people who receive them than for those who do without any equivalent.

Unusually, they go on to review a range of high caliber qualitative studies to identify four factors likely to contribute to the likelihood of early pregnancy: dislike of school, poor material circumstances, an unhappy home life, and low expectations and aspirations. 

The final part of the puzzle is to fit together the experimental studies with what young people themselves say, and to consider how far effective programs target the issues they identify.

A still smaller proportion of programs targeted at least two or three of the factors young people identified; none addressed any of the wider structural or systemic issues, such as poor housing, meager employment opportunities, lack of community networks or violence in home. 

Nevertheless, hopes are high that President Obama’s new Teen Pregnancy Prevention initiative will help to strengthen the evidence base: $75 million has been made available to fund replication studies of effective programs and a further $25 million for the development and evaluation of innovations. 

The money is relatively small in comparison to other Obama prevention initiatives, but the hope is that they it will be sufficient to improve the scientific foundation for future policy decisions. 

See:
Scher L S, Maynard R A and Stagner M (2006) Interventions Intended to Reduce Pregnancy-Related Outcomes Among Adolescents Campbell Systematic Review

Harden A, Burnton G, Fletcher A and Oakley A (2009) “Teenage pregnancy and social disadvantage: systematic review integrating controlled trials and qualitative studies” British Medical Journal 339:b4254 doi:10.1136/bmj.b4254