Maternal morbidity rates in a managed care population

OBJECTIVE: To identify and estimate prevalence rates of maternal morbidities by pregnancy outcome and selected covariates during the antepartum, intrapartum, and postpartum periods in a defined population of pregnant women. METHODS: We used electronic data systems of a large, vertically integrated, group-model health maintenance organization (HMO) to develop an algorithm that searched International Classification of Diseases, 9th Revision, Clinical Modification, codes for 38 predetermined groups of pregnancy-related complications among women enrollees of this HMO between January 1, 1998, and December 31, 2001. RESULTS: We identified 24,481 pregnancies among 21,011 women. Although prevalence and type of morbidity varied by pregnancy outcome, overall, 50% of women had at least one complication. The most common complications were anemia (9.3%), urinary tract infections (9.0%), mental health conditions (9.0%), hypertensive disorders (8.5%), and pelvic and perineal trauma (7.0%). CONCLUSION: A range of mild-to-severe pregnancy complications were identified using linked inpatient and outpatient databases. The most common complications we found usually do not require hospitalization so would be missed in studies that use only hospitalization data. Our data allowed examination of a broad scope of conditions and severity. These findings increase our understanding of the extent of maternal morbidity.