Background Attempts to address the 'problem' of teenage pregnancy need to further explore contraceptive use among young people at potentially greatest risk. We examine contraceptive use among a particularly vulnerable subgroup: girls who reported having had sex with more than one partner by age 16 years.

Methods Females (n = 435) completed questionnaires as part of the Scottish SHARE school-based sex education trial, reporting on contraceptive use at three episodes of sexual intercourse: first, first with most recent partner, and most recent.

Results Most used some form of contraception at each episode but a quarter reported withdrawal, putting on a condom before ejaculation or non-use. Some 57% of the girls reported using methods that suggested lower levels of pregnancy risk-taking behaviour at all three episodes, but 20% reported method use suggestive of greater risk-taking behaviour at one episode, 12% at two, and 11% at all three. In multivariate analysis, the factors associated with greater pregnancy risk-taking behaviour were living in social or rented accommodation, not knowing where to get prescription contraceptives, having pressurised or unexpected or spur of the moment sex, and not having talked to their partner about protection prior to sex.

Conclusions Most girls used an effective method of contraception at each episode of intercourse but a sizeable minority reported use of no contraception, or an ineffective method, which suggested greater pregnancy risk-taking behaviour; one in ten at all three episodes. Particular efforts are required to further understand and better target those girls who are putting themselves at repeated risk of pregnancy.