This paper explores the use of withdrawal as a harm reduction approach to adolescent pregnancy prevention and its association with condom use. Data come from a baseline survey of a randomised controlled trial to test the effectiveness of FLASH, a sexual health education curriculum. Study participants completed electronic self-report surveys in health classes in their first or second year of high school (age range 14.1-17.9, mean 15.3 years). One-hundred and ninety-one students (12% of full sample) reported engaging in vaginal intercourse in the 3 months prior to the survey; of these, 66.0% reported using withdrawal as a birth control method, without significant differences by race, gender, region or birth control beliefs. Withdrawal was often used in combination with condoms (55.5%), periodic abstinence (40.0%) and birth control pills (13.4%). The effectiveness of withdrawal and its prevalence suggest an opportunity to reflect on how withdrawal is taught -- moving from avoiding its use to a harm reduction approach to help sexually active youth avoid risk, reduce risk and reduce potential harm associated with sexual behaviours. Rather than focusing on withdrawal as risky, youth-serving professionals should acknowledge young people's efforts to prevent pregnancy and recognise the social and relational contexts of contraceptive choices.