To identify (1) the association between prepregnancy BMI (PP-BMI) and PPD symptoms, and (2) the association between PP-BMI and PPD symptoms after considering PNC utilization as a moderating variable. Data from the 2004 and 2005 Pregnancy Risk Assessment Monitoring System (PRAMS) were analyzed from 15 states. The study design utilized two risk-adjustment approaches. One approach included all women in the dataset and used statistical analyses to risk-adjust for pregnancy risk status, and the other approach, through a sensitivity analysis, modified the design of the study by truncating the sample to include only women with healthy pregnancies. An initial association was seen between obesity and PPD symptoms, and PNC and PPD symptoms in the multivariate analyses. However, the inclusion of case-mix variables into the multivariate models removed these associations. Overall, for both approaches, there was no indication of a moderating effect of PNC utilization. Results also revealed that many of the women were significantly affected by a variety of high-risk maternal morbidity (case-mix) variables. Although PNC is important for the health of mothers and babies, it does not appear to moderate the association of PP-BMI and PPD symptoms. However, since this study revealed associations between several high-risk maternal morbidities (included as casemix variables), and PPD symptoms, it is recommended that future research further investigate the possible association of these morbidities with PPD symptoms. For practice, it is suggested that PNC providers focus on their patients, and establish suitable interventions accordingly. © Springer Science+Business Media, LLC 2011.