Maternal smoking during pregnancy and offspring psychiatric disorder: a longitudinal birth cohort study

Background: There is evidence that prenatal stress and smoking during pregnancy both independently increase the risk of offspring psychopathology. Here we examine whether increased levels of self-reported stress is associated with increased smoking in a population of pregnant women, and whether prenatal smoking is associated with offspring psychiatric diagnoses independent of prenatal stress exposure.

Method: Using a longitudinal birth cohort, we used ordered logistic regressions to examine associations between maternal stress and smoking during pregnancy. We then used logistic regression analyses to examine associations between prenatal smoking and later offspring psychiatric disorders.

Results: A dose-response relationship was found between maternally reported stress and smoking during pregnancy. Pregnant women reporting severe stress were more likely to smoke compared to both the moderate stress and no stress groups, and those reporting moderate stress were significantly more likely to smoke compared to the no stress group. Smoking more than 5 cigarettes daily during pregnancy increased the risk of offspring personality disorder (OR 3.08, 95% CI 1.60-5.94) as well as developing any Axis 1 psychiatric disorder, inclusive of mood, anxiety and psychotic disorders (OR 1.45, 95% CI 1.04-2.04). After adjusting for parental psychiatric history and maternal self-reported stress during pregnancy, associations between smoking more than 5 cigarettes daily when pregnancy and offspring personality (OR 2.58 95% CI 1.32-5.06) disorder remained.

Conclusion: Exposure to cigarette smoking during gestation could impact a child's mental health. Smoking during pregnancy is a prime target for preventative interventions as unlike most other environmental risk factors, it is very amenable to change.