The impact of continuing illegal drug use on teenage pregnancy outcomes - a prospective cohort study

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 = 4.2,95% CI = 1.6-10.9; endocervical infections: OR = 2.6,95% CI = 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 = 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.