Patient Characteristics for Each Center
| Center | n | Women (n) | Delayed 4-h emptying (n) |
| Montefiore Medical Center | 130 | 89 (68.5%) | 34 (26.2%) |
| Baylor Scott & White Health | 100 | 74 (74.0%) | 23 (23.0%) |
| Ottawa Hospital | 101 | 77 (76.2%) | 17 (16.8%) |
| University of Vermont Hospital | 100 | 66 (66.0%) | 31 (31.0%) |
| Total | 431 | 306 (71.0%) | 105 (24.4%) |