The charts of all mothers who delivered at >36 weeks at Baylor University Medical Center between 1994 and 1998 were reviewed by one of the authors (DC). The Apgar scores, treatment modalities used, and outcome were recorded. MAS was defined both radiographically and clinically based on three criteria: 1) being born through MSAf; 2) having an abnormal chest radiograph; and 3) having respiratory distress that persisted beyond 24 hours of age and required oxygen. For criterion 2, the admission chest radiographs of all infants admitted to the NICU after delivery through MSAf were retrospectively reviewed by a staff radiologist who was unaware of the clinical diagnosis or reason for NICU admission; 35 radiographs were abnormal. Statistical significance was determined between groups using the Student t test for continuous variables and the chi-square test for categorical variables.