Table 1.
Maternal and newborn characteristics
| Characteristics | Background (n = 506 032) | ≥1 RBC (n = 11 842) | TR (n = 96) |
|---|---|---|---|
| Maternal characteristics | |||
| Age, y | |||
| <20 | 7 077 (1.4) | 171 (1.5) | 2 (2.1) |
| 20-34 | 387 323 (76.5) | 8 825 (74.5) | 65 (67.7) |
| 35-39 | 92 590 (18.3) | 2 285 (19.3) | 24 (25.0) |
| 40+ | 19 042 (3.8) | 561 (4.7) | 5 (5.2) |
| Mean (SD) | 31 (5.1) | 31 (5.3) | 32 (5.6) |
| Ethnicity (non-European) | 84 704 (16.7) | 2 468 (20.8) | 24 (25.0) |
| BMI, kg/m2 | |||
| <20 | 20 058 (5.9) | 499 (6.1) | 6 (9.4) |
| 20-30 | 301 834 (88.5) | 7 139 (87.5) | 52 (81.2) |
| 31-35 | 13 942 (4.1) | 364 (4.5) | 3 (4.7) |
| >35 | 5 283 (1.5) | 155 (1.9) | 3 (4.7) |
| Missing, n | 164 915 | 3 685 | 32 |
| Smoker | 50 041 (9.9) | 934 (7.9) | 9 (9.4) |
| Blood group O | 191 521 (37.8) | 4 618 (39.0) | 39 (40.6) |
| Previous deliveries | |||
| 0 | 230 570 (45.6) | 7 208 (60.9) | 56 (58.3) |
| 1 | 185 318 (36.6) | 3 117 (26.3) | 30 (31.3) |
| ≥2 | 90 144 (17.8) | 1 517 (12.8) | 10 (10.4) |
| Previous CS | 41 592 (8.2) | 1 396 (11.8) | 12 (12.5) |
| Diabetes mellitus | 1 894 (0.4) | 71 (0.6) | 1 (1.0) |
| Pregnancy and delivery related | |||
| Multiple pregnancy | 6 924 (1.4) | 682 (5.8) | 9 (9.4) |
| IVF | 8 708 (1.7) | 467 (3.9) | 4 (4.2) |
| Preeclampsia | 11 511 (2.3) | 796 (6.7) | 18 (18.8) |
| Labor induction | 51 701 (10.2) | 2 235 (18.9) | 29 (30.2) |
| Mode of delivery | |||
| Vaginal (spontaneous) | 388 950 (76.9) | 6 365 (53.7) | 52 (54.2) |
| Instrumental vaginal | 38 606 (7.6) | 2 075 (17.5) | 14 (14.6) |
| CS | 78 476 (15.5) | 3 402 (28.7) | 30 (31.3) |
| Placenta previa/accrete | 940 (0.2) | 259 (2.2) | 4 (4.2) |
| Placental abruption | 1 103 (0.2) | 225 (1.9) | 4 (4.2) |
| PPH/atonic | 10 354 (2.0) | 1 726 (14.6) | 14 (14.6) |
| Newborn characteristics | |||
| Premature (<34 + 0), wk | 10 387 (2.1) | 688 (5.8) | 12 (12.5) |
| Birth weight >4000 g | 90 697 (17.9) | 2 976 (25.1) | 21 (21.9) |
| Male sex | 259 958 (51.4) | 6 061 (51.2) | 51 (53.1) |
Unless otherwise noted, all data are n (%).
CS, cesarean section; IVF, in vitro fertilization; ; PPH, postpartum hemorrhage; SD, standard deviation.