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.