BackgroundTo date, little is known about the prevalence and risk factors for comorbid postpartum depression and anxiety. The aims of this study were to estimate the prevalence of comorbid depressive symptomatology and anxiety during the first 8 weeks postpartum and to identify risk factors. MethodsAs part of a longitudinal study conducted in a health region near Vancouver, British Columbia, a sample of 522 women completed mailed questionnaires at 1, 4, and 8 weeks postpartum. The presence of comorbid postpartum depressive symptomatology and anxiety was defined as having an Edinburgh Postnatal Depression Scale (EPDS) score of ≥10 and a State Trait Anxiety Inventory (STAI)-state anxiety score of ≥40 at the same time point. Risk factors associated with comorbidity were examined using generalized estimating equations (GEE). ResultsThe prevalence of comorbid depressive symptomatology and anxiety was 13.1% during the first 8 weeks postpartum. In multivariable analysis, immigration within past 5 years (adjusted odds ratio (AOR)=8.03, 95% CI 3.43–18.77), maternal vulnerable personality (AOR=1.42, 95% CI 1.02–1.97 for 1 SD increase), child care stress (AOR=1.66, 95% CI 1.18–2.35 for 1 SD increase) and perceived stress (AOR=3.00, 95% CI 2.01–4.47 for 1 SD increase) predicted a higher risk of comorbidity. Conversely, high breastfeeding self-efficacy (AOR=0.66, 95% CI 0.49–0.88 for 1 SD increase), maternal self-esteem (AOR=0.66, 95% CI 0.45–0.97 for 1 SD increase), and partner support (AOR=0.73, 95% CI 0.55–0.98 for 1 SD increase) were associated with a lower risk of developing comorbidity. LimitationIn this study, women who were single or from non-Caucasian ethnic groups were underrepresented. ConclusionsComorbid postpartum depressive symptomatology and anxiety is a common condition with little known about risk factors. Additional research is warranted to develop strategies to reliably identify women with this comorbid condition and to determine effective treatment options.