Table 5.
Maternal and gestation 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 | |
|---|---|---|---|---|
| Maternal age (years), mean ± SD | 32.60 ± 5.15 | 33.81 ± 5.06 | 1.430 | 0.161 |
| Advanced maternal age (>35 years old) | 399 (24.5%) | 15 (30.6%) | 0.958 | 0.328 |
| Maternal height (cm) | 157.78 ± 4.95 | 158.04 ± 5.01 | 0.354 | 0.725 |
| Maternal weight at delivery (kg) | 65.07 ± 8.97 | 67.18 ± 9.11 | 1.561 | 0.125 |
| Maternal BMI at delivery (kg/m2), mean ± SD | 26.13 ± 3.35 | 26.86 ± 3.66 | 1.483 | 0.138 |
| Married (%) | 1557 (95.6%) | 45 (91.8%) | 1.542 | 0.214 |
| Prior miscarriages (%) | 816 (50.1%) | 22 (44.9%) | 0.513 | 0.474 |
| Prior cesarean delivery | 561 (34.4%) | 17 (34.7%) | 0.001 | 0.970 |
| Assisted reproductive techniques | 171 (10.5%) | 5 (10.2%) | 0.004 | 0.947 |
| Twins | 67 (4.1%) | 2 (4.1%) | 0.001 | 0.991 |
| Anterior placenta | 518 (45.2%) | 12 (34.3%) | 1.647 | 1.199 |
| Complete placenta previa | 653 (40.1%) | 17 (34.7%) | 0.577 | 0.448 |
| Placenta accreta spectrum | 258 (15.8%) | 7 (14.3%) | 0.086 | 0.769 |
| Predelivery hemoglobin (g/L) | 107.63 ± 17.50 | 109.64 ± 17.86 | 0.758 | 0.452 |
| Predelivery anemia (hemoglobin < 110 g/L) | 811 (52.5%) | 20 (42.6%) | 1.806 | 0.179 |
| Antepartum hemorrhage | 499 (30.6%) | 19 (38.8%) | 1.478 | 0.224 |