Rate and causes of severe maternal morbidity at readmission: California births in 2008-2012.

OBJECTIVE: To determine the rate, maternal characteristics, timing, and indicators of severe maternal morbidity (SMM) that occurs at postpartum readmission. STUDY DESIGN: Women with a birth in California during 2008-2012 were included in the analysis. Readmissions up to 42 days after delivery were investigated. SMM was defined as presence of any of the 21 indicators defined by ICD-9 codes. RESULTS: Among 2,413,943 women with a birth, SMM at readmission occurred in 4229 women. Of all SMM, 12.1% occurred at readmission. Over half (53.5%) of the readmissions with SMM occurred within the first week after delivery hospitalization. The most common indicators of SMM were blood transfusion, sepsis, and pulmonary edema/acute heart failure. CONCLUSION: Twelve percent of SMM was identified at readmission with the majority occurring within 1 week after discharge from delivery hospitalization. Because early readmission may reflect lack of discharge readiness, there may be opportunities to improve care.