“…First, fewer data are available on individual patients than in studies based on medical chart reviews. For example, the aforementioned study of 83 pregnant patients undergoing EGD reported data on procedure indication, medications, maternal procedural complications, comorbidities, vital signs at beginning endoscopy, and others, 14 which were unavailable for analysis in the Registry Study 13 (Table 1). Second, the medical chart can be re-reviewed in chart-based studies to mine new parameters as becomes necessary.…”