The ‘whys’ of substance use in pregnancy

New research by Canadian investigators points to depression as the number one risk factor among pregnant women for use of alcohol, tobacco, and cannabis during pregnancy. Policy interventions targeting at-risk women, the authors say, are needed to improve maternal mental health.

Published in The Journal of Neonatal-Perinatal Medicine, the findings are from a retrospective cohort study of more than 25,000 pregnant women from Southwestern Ontario. The data analyzed were extracted from perinatal and neonatal diabetes at tertiary hospital in London, Ontario. Maternal postal codes and a Geographic Information System were used to map neighborhood-level socioeconomic values.

The primary objective of the study was an assessment of relative effects of socioeconomic, demographic, and mental health risk factors associated with substance use in pregnancy. Birth outcomes also were evaluated, using an Apgar score < 7 and fetal macrosomia as secondary outcomes. Separate logistic regressions were computed for all outcome variables.

Rates of use of alcohol, tobacco, and cannabis during pregnancy in the study population were 1.9%, 16.2%, and 2.3%, respectively.  The researchers found that depression in pregnancy was associated with a 2.15 times higher risk of use of alcohol (95% CI 1.60-2.90). 1.70 times higher risk of smoking tobacco (95% CI 1.48-1.95), and 2.56 times higher risk of using cannabis (95% CI 1.95-3.35).

Having anxiety also increased the risk of substance use in pregnancy, whereas there was an inverse relationship between maternal age and use of alcohol, tobacco, and cannabis. Looking at outcomes in the neonates, the investigators found that adverse outcomes were associated with maternal overweight and obesity, gestational diabetes, and insulin-dependent diabetes.