Smoking During Pregnancy as a Predictor and a Potential Mediator in the Relationship between Marital Status and Postpartum Depression

Introduction: Smoking is associated with depression and other mood disorders. There is consistent evidence in the literature that social support is a major predictor of postpartum depression. Based on these findings, marital status and smoking during pregnancy were examined as potential predictors. We investigated smoking during pregnancy as a possible mediator within the relationship between marital status during pregnancy and postpartum depression. Methods: Participants were recruited from the postpartum floor at a Providence, RI hospital between 2004-2009. Two interviews were conducted, one at the hospital and one at home 6-8 weeks following delivery. Postpartum depression was measured at the in-home interview using the Edinburgh Postnatal Depression Scale. A score of 13 or above was “depressed.” Prediction models were fit for the two exposures and depression. Baron-Kenney methodology was implemented. Results: In our analytic sample (N=523, Mean Age: 28.7 (18.0-40.8)), 6.9% met the criteria for postpartum depression. 61.3% were married/engaged and 38.7% were single/divorced/separated/widowed. 25.2% smoked 1-10 cigarettes/day and 10.3% smoked 11+ cigarettes/day. Marital status was associated with lower postpartum depression (OR=.43, 95%:CI(.19 -.99)) after adjusting for covariates. In a separate model, smoking during pregnancy was significant after adjusting for covariates (OR=5.76, 95%:CI(2.50-13.24). When smoking was added as a potential mediator, the association between marital status and depression was no longer significant (OR=0.49, 95%:CI(0.23-1.03)). Conclusions: We found that marital status and smoking during pregnancy were predictors of postpartum depression. Smoking appears to mediate the relationship between marital status and depression. Understanding this mechanism may lead to targeted smoking cessation interventions.