Table 1.
Descriptive and obstetric characteristics of women who attempted vaginal birth after cesarean delivery by inter-delivery interval length
| Variable | Inter-delivery interval (completed month) | P-value | |||
|---|---|---|---|---|---|
| Less than 24 (n = 28) | 24–59 (n = 395) | 60–119 (n = 521) | 120 or more (n = 112) | ||
| Maternal age (y, s.d.) | 31.0 ± 3.3 | 31.4 ± 4.2 | 32.1 ± 4.2 | 32.2 ± 4.2 | 0.061 |
| Maternal Nationality (%) | 0.730 | ||||
| Han | 28 (100.0) | 384 (97.2) | 510 (97.9) | 110 (98.2) | |
| Other minorities | 0 | 11 (2.8) | 11 (2.1) | 2 (1.8) | |
| Parity (times, s.d.) | 1.4 ± 1.0 | 1.2 ± 0.4 | 1.3 ± 0.5 | 1.5 ± 0.7 | < 0.001 |
| Number of CD (%) | 0.034 | ||||
| 1 | 27 (96.4) | 393 (99.5) | 520 (99.7) | 112 (100.0) | |
| 2 | 1 (3.6) | 2 (0.5) | 1 (0.2) | 0 | |
| Any prior vaginal delivery (%) | 4 (14.3) | 56 (14.2) | 124 (23.8) | 43 (38.4) | < 0.001 |
| BMI at the first prenatal visit (kg/m2 s.d.) | 21.7 ± 3.2 | 21.3 ± 2.8 | 21.6 ± 3.1 | 22.4 ± 3.2 | 0.007 |
| BMI at TOLAC delivery (kg/m2, s.d.) | 25.7 ± 3.5 | 25.9 ± 2.9 | 26.5 ± 3.2 | 26.8 ± 3.2 | 0.003 |
| Estimated fetal weight at TOLAC delivery (g) | 2868 ± 593 | 3043 ± 420 | 3049 ± 471 | 2914 ± 513 | 0.033 |
| Estimated fetal head circumference (mm, s.d.) | 311 ± 31 | 333 ± 233 | 328 ± 186 | 307 ± 57 | 0.694 |
| Lower uterine segment thickness (mm, s.d.) | 2.9 ± 0.3 | 2.7 ± 0.6 | 2.6 ± 0.6 | 2.8 ± 0.5 | 0.099 |
| Cervical dilatation on admission at TOLAC delivery (5–6 cm) | 4 (19.0) | 56 (17.4) | 80 (20.9) | 17 (23.6) | 0.878 |
| Cervical effacement on admission at TOLAC delivery (80–100%) | 17 (81.0) | 253 (78.6) | 309 (80.3) | 56 (77.8) | 0.891 |
| Cervical score (score, s.d.) | 7.9 ± 2.3 | 7.7 ± 2.7 | 8.1 ± 2.7 | 8.1 ± 2.9 | 0.215 |
| Pre-existing medical condition (%) | |||||
| GDM | 5 (17.9) | 65 (16.5) | 114 (21.9) | 27 (24.1) | 0.138 |
| Preeclampsia | 4 (14.3) | 6 (1.5) | 9 (1.7) | 11 (9.8) | < 0.001 |