The impact of continuing illegal drug use on teenage pregnancy outcomes—a prospective cohort study Julie A. Quinlivan a, * , Sharon F. Evans b Objective To evaluate the impact of continuing illegal drug use on teenage pregnancy outcomes. Design Prospective cohort study. Setting Three Australian obstetric hospitals. Sample Four hundred and fifty-six teenage antenatal patients. Methods Teenage antenatal patients were interviewed and completed questionnaires to establish their pattern of non-prescription drug use before and during pregnancy. Illegal drug use data provided by the participants were validated in a subgroup of 180 who were interviewed six months postpartum. Antenatal, intrapartum and postnatal outcomes were collated independently. Data were analysed using SAS. Main outcome measures Antenatal co-morbidity, delivery and newborn outcomes. Results In the cohort, 20.3% used marijuana throughout their pregnancy. However, 33.5% of these were multidrug users. The remaining 79.6% did not use illegal drugs throughout pregnancy (non-users). However, half the ‘non-users’ were ‘ex-users’ who ceased drug use immediately before or during early pregnancy. Illegal drug use was associated with an increased incidence of concurrent cigarette and alcohol use (both OR > 4.1 and P < 0.0001) and social and psychiatric morbidity (all OR > 1.95 and P < 0.001). Multidrug use was associated with a significant increase in the incidence of chlamydial and other endocervical infections (chlamydia: OR ¼ 4.2, 95% CI ¼ 1.6 – 10.9; endocervical infections: OR ¼ 2.6, 95% CI ¼ 1.1–5.7). After controlling for significant covariates, and in the setting of good antenatal care, the only difference in outcome was a significant linear trend towards an increased incidence of threatened preterm labour across the three groups ( P ¼ 0.02). Of note, there were no effects on birthweight, birthweight ratio or preterm birth. Conclusion Good antenatal care may be able to ameliorate many adverse pregnancy outcomes in teenagers who use illegal drugs throughout pregnancy. The high levels of coexisting psychosocial morbidity are a concern for future mothercrafting. INTRODUCTION Prime Minister Tony Blair, in his speech to Parliament to launch the UK Government’s Social Exclusion Unit pro- gramme of action on teenage pregnancy, identified concur- rent drug use as a leading factor in adverse healthcare outcomes in teenage mothers 1 . Yet little prospective data have evaluated the impact of drug use in teenage pregnancy. Retrospective studies have been hampered by a lack of data on relevant co-factors that may confound key outcomes. The coexistence of drug abuse and teenage pregnancy is well recognised. An American review commented that 80% of teenagers reported being sexually active by age 19 years. Furthermore, 80%, 64% and 41% reported regular use of alcohol, cigarettes and marijuana, respectively 2 . Marijuana is a particular problem in the setting of teenage pregnancy as it is a drug of choice in young patients with addiction problems. Furthermore, illegal drug use is linked to early discontinuation of schooling and social isolation, factors that are poor companions to teenage parenthood 3,4 . However, many teenage mothers describe pregnancy as a time for self-improvement and positive interventions are well received 4,5 . If ongoing problems of addiction can be identified, then intervention programmes can be imple- mented to improve outcomes for the mother and child 1,6 . The need to provide supportive interventions to optimise maternal – infant care is most marked in respect to drug- using women, who consistently score higher on measures of child abuse potential compared with non-using controls 7 . Data suggest that teenage mothers also have an increased potential for child abuse compared with older controls 8 . This potential for abuse has been translated into an increase in rates of non-voluntary foster care and non-accidental injury. A large epidemiologic study found that illegal drug use and teenage motherhood were independent and additive BJOG: an International Journal of Obstetrics and Gynaecology October 2002, Vol. 109, pp. 1148–1153 D RCOG 2002 BJOG: an International Journal of Obstetrics and Gynaecology PII:S1470-0328(02)01936-5 www.bjog-elsevier.com a Department of Obstetrics and Gynaecology, The University of Melbourne, Melbourne, Victoria, Australia b Womens and Infants Research Foundation and Department of Obstetrics and Gynaecology, University of Western Australia, Perth Western Australia, Australia * Correspondence: Dr J. A. Quinlivan, Department of Obstetrics and Gynaecology, The University of Melbourne, 132 Grattan Street, Carlton 3053, Australia.