Table 1.
Characteristics of study population
| Variable | Study population (n=10,295) (%) | Groups | ||
| NVD (n=9304) (%) | EmCS (n=991) (%) | P value* | ||
| Demographic characteristics of pregnant women | ||||
| Mean age (years) | 28.08±3.51 | 28.02±3.53 | 28.59±3.22 | < 0.001 |
| Age categories (years) | ||||
| <25 | 2121 (20.60) | 1986 (21.35) | 135 (13.62) | < 0.001 |
| 25–29 | 5179 (47.30) | 4649 (49.96) | 530 (53.48) | |
| 30–35 | 2512 (24.40) | 2240 (24.08) | 272 (27.45) | |
| ≥35 | 483 (4.70) | 429 (4.61) | 54 (5.45) | |
| Height (cm) | 161.6±0.046 | 161.6±0.045 | 161.8±0.048 | 0.313 |
| Gestational age (weeks) | 39.41±1.41 | 39.41±1.43 | 39.43±1.28 | 0.555 |
| Weight before pregnancy (kg) | 51.35±5.41 | 51.17±5.29 | 53.03±6.19 | < 0.001 |
| BMI before pregnancy (kg/m2) | 19.67±2.10 | 19.61±2.03 | 20.31±2.58 | < 0.001 |
| Weight at delivery (kg) | 68.71±8.18 | 68.48±8.06 | 70.89±8.88 | < 0.001 |
| BMI at delivery (kg/m2) | 26.30±2.92 | 26.21±2.83 | 27.13±3.56 | < 0.001 |
| Pregnancy history | ||||
| Gravidity | ||||
| Primigravidity | 6165 (59.88) | 5512 (59.24) | 653 (65.89) | < 0.001 |
| Multigravidas | 4130 (40.12) | 3792 (40.76) | 338 (34.11) | |
| Parity | ||||
| Nulliparous | 8775 (85.24) | 7830 (84.16) | 946 (95.46) | < 0.001 |
| Multiparous | 1519 (14.76) | 1474 (15.84) | 45 (4.54) | |
| Previous cesarean section | ||||
| Yes | 40 (0.39) | 36 (0.39) | 4 (0.39) | 0.936 |
| No | 10 255 (99.61) | 9268 (99.61) | 987 (99.61) | |
| Perinatal complications | ||||
| Characters of amniotic fluid | ||||
| Clear | 7459 (72.45) | 6977 (74.99) | 482 (48.64) | < 0.001 |
| Stage I | 239 (2.33) | 214 (2.30) | 25 (2.52) | |
| Stage II | 194 (1.88) | 185 (1.99) | 9 (0.91) | |
| Stage III/bloody | 2403 (23.34) | 1928 (20.72) | 475 (47.93) | |
| Umbilical cord status | ||||
| Normal | 6452 (62.67) | 5928 (63.71) | 524 (52.88) | < 0.001 |
| Cord entanglement | 3547 (34.45) | 3136 (33.71) | 411 (41.47) | |
| Torsion of umbilical cord | 296 (2.88) | 240 (2.58) | 56 (5.65) | |
| HDP* | ||||
| Yes | 429 (4.17) | 362 (3.89) | 67 (6.76) | < 0.001 |
| No | 9866 (95.83) | 8942 (96.11) | 924 (93.24) | |
| Low lying placenta | ||||
| Yes | 40 (0.39) | 38 (0.41) | 2 (0.20) | 0.320 |
| No | 10 255 (99.61) | 9266 (99.59) | 989 (99.80) | |
| Placental abruption | ||||
| Yes | 40 (0.39) | 36 (0.39) | 4 (0.40) | 0.936 |
| No | 10 255 (99.61) | 9268 (99.61) | 987 (99.60) | |
| Oligohydramnios | ||||
| Yes | 72 (0.70) | 40 (0.43) | 32 (3.23) | < 0.001 |
| No | 10 223 (99.3) | 9264 (99.57) | 959 (96.77) | |
| Hydramnion | ||||
| Yes | 50 (0.49) | 36 (0.39) | 14 (1.41) | < 0.001 |
| No | 10 245 (99.51) | 9268 (99.61) | 977 (98.59) | |
| Neonatal features | ||||
| Birth weight (g) | 3293.78±415.51 | 3275.88±413.38 | 3461.84±397.55 | < 0.001 |
| Neonatal weight (g) | ||||
| <2500 | 260 (2.53) | 252 (2.71) | 8 (0.81) | < 0.001 |
| 2500–4000 | 9581 (93.06) | 8698 (93.48) | 883 (89.10) | |
| ≥4000 (macrosomia) | 454 (4.41) | 354 (3.81) | 100 (10.09) | |
| Gender | ||||
| Male | 5372 (52.18) | 4806 (51.66) | 566 (57.11) | 0.001 |
| Female | 4923 (47.82) | 4498 (48.34) | 425 (42.89) | |
| Labor process | ||||
| Induction of labor | ||||
| Yes | 1180 (11.46) | 822 (8.83) | 358 (36.13) | < 0.001 |
| No | 9115 (88.54) | 8482 (91.17) | 633 (63.87) | |
| Epidural anesthesia | ||||
| Yes | 6485 (62.99) | 5855 (62.92) | 630 (63.57) | 0.052 |
| No | 3810 (37.01) | 3449 (37.08) | 361 (36.43) | |
*Two-sided p<0.05 was considered statistically significant, and the bold typeface shows the significant data.
BMI, body mass index; EmCS, emergency cesarean section; HDP, hypertensive disorders of pregnancy; NVD, normal vaginal delivery.