BackgroundAnxiety in pregnancy is one of the strongest risk factors for postpartum depression (PPD), and high worry is a hallmark of many anxiety disorders. We sought to determine whether the Penn State Worry Questionnaire (PSWQ), designed for the general population, could identify high worry in pregnancy and predict the development of PPD symptoms (PPDS). MethodsWe followed women (N = 295) with and without mood and anxiety disorders across pregnancy and up to 6 months postpartum. Diagnoses were confirmed by SCID and by an experienced perinatal psychiatrist, and we administered the PSWQ and the Edinburgh Postnatal Depression Scale (EPDS) at up to 6 time points. We determined the trajectory of worry across time and its relationship to PPDS. ResultsWomen with a history or current diagnosis of major depressive disorder (MDD) or generalized anxiety disorder (GAD) were more likely to experience high antenatal worry (defined as PSWQ >60), p < .004 for MDD and <0.001 for all others. High antenatal worry was the only significant predictor of PPDS, with an OR of 3.91 (95% CI 1.44–10.65); neither psychiatric diagnosis nor elevated antenatal depressive symptoms was significantly associated with PPDS in a multivariate model. LimitationsOur study used self-report measures in a largely homogeneous population, which may limit the generalizability of our results. ConclusionsThe PSWQ may be a useful clinical tool in pregnancy. High worry is a strong predictor of PPDS, and is a better predictor of PPDS than psychiatric diagnosis or elevated antenatal depressive symptoms in this population.