Objectives To describe contraceptive risk and compensatory behaviour, using condoms or emergency contraception (EC), in young people in education aged 16–24 years.

Design Cross-sectional study.

Subjects A total of 1135 students aged 16–24 years.

Setting Educational establishments in and around London, UK.

Results Seventy-six percent of women and 55% of men reported having experienced sex either without contraception or when a condom split or came off. Most participants (or their sexual partners) who reported such risks had compensated by using EC at least once (72% women, 55% men) but only a minority had compensated on each occasion of risk (37% women and 22% men). Of the oral contraceptives users the majority (83%) had experienced a pill 'problem' and the majority of these participants had compensated for such problems by using condoms (79%). Fewer than half of the women who experienced pill problems (45%) compensated by using condoms on each occasion. Less than a quarter (23%) of those who experienced pill problems but did not compensate by using condoms ever compensated by using EC.

Conclusions This study demonstrates high levels of primary contraceptive risk and low levels of consistent compensatory condom or EC use. The findings suggest that there would be large increases in EC use and repeated use if all primary contraceptive risks were followed by compensatory action. Interventions to increase contraceptive use should focus not only on initiation of contraception use but acknowledge that risks do happen and promote both continuing use and compensatory behaviour.