The broad goal of this project is to delineate the clinical, psychosocial, and in particular, pharmacologic predictors of BPD recurrence during pregnancy. Preliminary findings suggest that inadequate treatment is a particularly robust predictor of prenatal BPD recurrence. Consequently, a specific emphasis will be placed on investigating the recurrence risk associated with suboptimal pharmacotherapy occurring as a result of medication discontinuation or declining drug concentrations secondary to increased prenatal clearance.