Table 6.
Labor characteristics of the participant pregnant women by Rh-positive vs. Rh-negative blood groups.
| Rh-positive (n = 1629, 97.1%) | Rh-negative (n = 49, 2.9%) | t/Z/χ2 value | p value | |
|---|---|---|---|---|
| Gestational age at delivery (week), mean ± SD | 37.03 ± 2.54 | 37.37 ± 2.25 | 0.904 | 0.366 |
| Preterm birth (<37 weeks) | 674 (42.2%) | 17 (36.2%) | 0.676 | 0.411 |
| Emergency admission | 1445 (88.7%) | 44 (89.8%) | 0.057 | 0.812 |
| Cesarean delivery | 1235 (75.8%) | 40 (81.6%) | 0.883 | 0.347 |
| Estimated blood loss (mL), median (IQR) | 500 (380-1200) | 500 (350-800) | 1.262 | 0.207 |
| Postpartum hemorrhage | 382 (23.4%) | 9 (18.4%) | 0.688 | 0.407 |
| Cesarean hysterectomy | 18 (1.1%) | 1 (2.0%) | 0.372 | 0.542 |
| Transfusion of blood products | 543 (33.3%) | 10 (20.4%) | 3.597 | 0.058 |
| Postdelivery hemoglobin (g/L) | 102.01 ± 15.56 | 103.31 ± 14.49 | 0.551 | 0.581 |
| Postdelivery anemia (hemoglobin < 110 g/L) | 952 (70.4%) | 32 (71.1%) | 0.010 | 0.920 |
| Placental length (cm) | 19.21 ± 2.34 | 19.35 ± 2.14 | 0.409 | 0.682 |
| Placental width (cm) | 18.67 ± 2.21 | 19.33 ± 2.37 | 2.033 | 0.062 |
| Placental depth (cm) | 2.22 ± 0.42 | 2.19 ± 0.41 | 0.386 | 0.701 |
| Placental surface area (cm2) | 285.62 ± 73.55 | 296.74 ± 68.16 | 1.122 | 0.267 |
| Placental volume (cm3) | 443.06 ± 322.98 | 545.94 ± 300.76 | 0.894 | 0.376 |
| Placental weight (g) | 581.18 ± 174.13 | 614.27 ± 130.90 | 1.494 | 0.143 |
| Male newborn | 950 (58.3%) | 25 (51.0%) | 1.041 | 0.308 |
| Neonatal asphyxia | 120 (9.2%) | 1 (5.9%) | 2.016 | 0.156 |
| Admission to the neonatal intensive care unit | 365 (22.4%) | 9 (18.4%) | 0.448 | 0.503 |
| Apgar score of <7 at 1 min | 110 (6.8%) | 1 (2.0%) | 1.710 | 0.191 |
| Apgar score of <7 at 5 min | 14 (0.9%) | 0 (0.0%) | 0.425 | 0.999 |
| Apgar score of <7 at 10 min | 5 (0.3%) | 0 (0.0%) | 0.151 | 0.999 |