Effect of an intervention to prevent unwanted pregnancy in adolescents. A randomized,prospective study from Nordland County,Norway, 1999–2001

The aim of this study is to evaluate the effect of an intervention designed to prevent unwanted pregnancy in adolescents. A stratified sample of 74 compulsory schools was drawn at random from all compulsory schools in the county of Nordland in northern Norway. Of these 54 schools were willing to participate. The participating schools were assigned to four different groups according to a Solomon four‐group design. A total of 1183 pupils gave their informed consent for participation. For the intervention, a textbook in sex education was developed and handed out to pupils and teachers participating in the intervention groups. Data collections were carried out 1999–2001. The results from this study stem from data collected at post‐test 1. The individual was used as unit of analysis. Among adolescents who made their coital debut between the pre‐test and post‐test 1, more of those in the intervention group than in the pre‐test group reported use of contraception during first sexual intercourse. No other statistically significant effect of the intervention was found. The reason may be biased drop‐out. Copyright © 2003 John Wiley & Sons, Ltd.