[영문]AB Background: Elevation in prepregnancy body mass index (BMI) has been linked to a host of perinatal complications, but increases in charges or costs associated with obesity during pregnancy have not been quantified. Methods: To evaluate the economic impact of obesity as a diagnosis on hospitalizations of pregnant women, we performed descriptive, univariate, and multivariable analysis of the 1999 to 2005 Nationwide Inpatient Sample, a nationally representative sample of admissions to US community hospitals. Results: Hospitalizations with a diagnosis of obesity were rare (0.7%), but when obesity was a diagnosis, it was associated with significant increases in length of stay (LOS), charges, and costs. Cesarean section was more frequent among women hospitalized with a diagnosis of obesity, with increases in this procedure across nearly every pregnancy-related diagnostic category. Controlled for cesarean section, diagnosed obesity was associated with significant increases in LOS (0.55 day), charges (