Table 1.
Baseline characteristics of the unmatched cohort, stratified by approach to delivery
| Characteristic | ERCD N = 5500 | TOL N = 6782 | SDiff |
|---|---|---|---|
| Demographics | |||
| Caucasian | 2703 (49.1) | 2500 (36.9) | 25.0 |
| Married | 3597 (65.4) | 3844 (56.7) | 18.0 |
| Prenatal care | 5466 (99.4) | 6667 (98.3) | 10.1 |
| Private medical payment at delivery | 3018 (54.9) | 2962 (43.7) | 22.5 |
| Body mass index at delivery | 32.4 (28.7, 37.4) | 30.6 (27.2, 34.8) | 31.2 |
| Maternal age | 29 (25, 33) | 28 (24, 32) | 15.0 |
| Past obstetric history | |||
| Prior cesarean indication of CPD/FTP/failed forceps or vacuum | 3031 (55.1) | 2474 (36.5) | 38.1 |
| < 2 years since prior cesarean delivery | 577 (10.5) | 566 (8.3) | 7.3 |
| No prior vaginal delivery | 4682 (85.1) | 3681 (54.3) | 71.3 |
| No prior VBAC | 5235 (95.2) | 4584 (67.6) | 75.8 |
| Current pregnancy history | |||
| EDC confirmation by first trimester US | 1814 (33.0) | 1615 (23.8) | 20.4 |
| Diabetes | 437 (7.9) | 240 (3.5) | 19.0 |
| Asthma | 380 (6.9) | 493 (7.3) | −1.4 |
| Thyroid disease | 173 (3.1) | 148 (2.2) | 6.0 |
| Seizure disorder | 38 (0.7) | 43 (0.6) | 0.7 |
| Chronic hypertension | 70 (1.3) | 40 (0.6) | 7.1 |
| Heart disease | 63 (1.1) | 68 (1.0) | 1.4 |
| Cigarette use | 675 (12.3) | 954 (14.1) | −5.3 |
| Alcohol use | 153 (2.8) | 228 (3.4) | −3.4 |
| Street drug use | 108 (2.0) | 263 (3.9) | −11.4 |
| Preterm labor requiring tocolysis | 60 (1.1) | 124 (1.8) | −6.2 |
| Infection | 1502 (27.3) | 2154 (31.8) | −9.8 |
| Antepartum antibiotic administration | 1233 (22.4) | 1677 (24.7) | −5.4 |
| Gestational hypertension/preeclampsia | 208 (3.8) | 178 (2.6) | 6.6 |
| Other maternal co-morbiditya | 85 (1.5) | 160 (2.4) | −5.9 |
ERCD, elective repeat cesarean; TOL, trial of labor; SDiff, the standardized difference; CPD cephalopelvic disproportion; FTP, failure to progress; VBAC, vaginal birth after a prior cesarean; EDC, estimated date of confinement; US, ultrasound
Data presented as n (%) or median (interquartile range)
a
Other maternal co-morbidity includes, prior to admission, abruption, pulmonary edema, any steroid use, renal disease or connective tissue disorder.