Objectives To describe statewide SMM trends in Iowa from 2009 to 2014 and identify maternal characteristics associated with SMM, overall and by age group. Methods We used 2009–2014 linked Iowa birth certificate and hospital discharge data to calculate SMM based on a 25-condition definition and 24-condition definition. The 24-condition definition parallels the 25-condition definition, but excludes blood transfusions. We calculated SMM rates for all delivery hospitalizations (N = 196,788) using ICD-9-CM diagnosis and procedure codes. We used log-binomial regression to assess the association of SMM with maternal characteristics, overall and stratified by age groupings. Results In contrast to national rates, Iowa’s 25-condition SMM rate decreased from 2009 to 2014. Based on the 25-condition definition, SMM rates were significantly higher among women <20 years and >34 years compared to women 25–34 years. Blood transfusion was the most prevalent indicator, with hysterectomy and disseminated intravascular coagulation (DIC) among the top five conditions. Based on the 24-condition definition, younger women had the lowest SMM rates and older women had the highest SMM rates. SMM rates were also significantly higher among racial/ethnic minorities compared to non-Hispanic white women. Payer was the only risk factor differentially associated with SMM across age groups. First trimester prenatal care initiation was protective for SMM in all models. Conclusions High rates of blood transfusion, hysterectomy, and DIC indicate a need to focus on reducing hemorrhage in Iowa. Both younger and older women and racial/ethnic minorities are identified as high risk groups for SMM that may benefit from special consideration and focus.