Table 1.
Maternal and infant characteristics, overweight- or obesity-related pregnancy complications and rates of asphyxia-related outcomes. Preterm singleton infants without congenital malformation in Sweden 1997–2011
| Characteristics | No. of infants (%) | Apgar score 0–3 at 5 minutes | Apgar score 0–3 at 10 minutes | Neonatal seizures | IVH grades 1–4 | IVH grades 3–4 |
|---|---|---|---|---|---|---|
| No. of cases (rate)a | No. of cases (rate)a,b | No. of cases (rate)a | No. of cases (rate)a | No. of cases (rate)a | ||
| Total | 62 499 (100) | 766 (12.3) | 438 (7.0) | 304 (4.9) | 895 (14.3) | 216 (3.5) |
| Maternal characteristics | ||||||
| Age at delivery (years) | ||||||
| <19 | 1386 (2.2) | 28 (20.2) | 14 (10.1) | 2 (1.4) | 23 (16.6) | 7 (5.1) |
| 20–24 | 9128 (14.6) | 112 (12.3) | 75 (8.2) | 41 (4.5) | 108 (11.8) | 24 (2.6) |
| 25–29 | 19 240 (30.8) | 212 (11.0) | 127 (6.6) | 79 (4.1) | 266 (13.8) | 56 (2.9) |
| 30–34 | 19 881 (31.8) | 232 (11.7) | 130 (6.5) | 114 (5.7) | 280 (14.1) | 69 (3.5) |
| ≥35 | 12 864 (20.6) | 182 (14.1) | 92 (7.2) | 68 (5.3) | 218 (16.9) | 60 (4.7) |
| Parity | ||||||
| 1 | 33 869 (54.2) | 394 (11.6) | 223 (6.6) | 155 (4.6) | 498 (14.7) | 117 (3.5) |
| 2–3 | 24 550 (39.3) | 311 (12.7) | 186 (7.6) | 126 (5.1) | 337 (13.7) | 85 (3.5) |
| ≥4 | 4080 (6.5) | 61 (15.0) | 29 (7.1) | 23 (5.6) | 60 (14.7) | 14 (3.4) |
| Cigarette smoking during pregnancy | ||||||
| No | 49 966 (79.9) | 546 (10.9) | 317 (6.3) | 229 (4.6) | 638 (12.8) | 156 (3.1) |
| Yes | 7368 (11.8) | 86 (11.7) | 48 (6.5) | 36 (4.9) | 103 (14.0) | 23 (3.1) |
| Data missing | 5165 (8.3) | 134 (25.9) | 73 (14.2) | 39 (7.6) | 154 (29.8) | 37 (7.2) |
| Height (cm) | ||||||
| <155 | 3006 (4.8) | 44 (14.6) | 29 (9.6) | 14 (4.7) | 54 (18.0) | 14 (4.7) |
| 155–164 | 24 649 (39.4) | 288 (11.7) | 174 (7.1) | 103 (4.2) | 340 (13.8) | 83 (3.4) |
| 165–174 | 28 714 (45.9) | 346 (12.0) | 189 (6.6) | 152 (5.3) | 401 (14.0) | 95 (3.3) |
| ≥175 | 4360 (7.0) | 56 (12.8) | 34 (7.8) | 21 (4.8) | 51 (11.7) | 10 (2.3) |
| Data missing | 1770 (2.8) | 32 (18.1) | 12 (6.8) | 14 (7.9) | 49 (27.7) | 14 (7.9) |
| Education (years) | ||||||
| ≤11 | 17 792 (28.5) | 268 (15.1) | 171 (9.6) | 97 (5.5) | 262 (14.7) | 70 (3.9) |
| 12–14 | 25 120 (40.2) | 288 (11.5) | 154 (6.1) | 118 (4.7) | 359 (14.3) | 82 (3.3) |
| ≥15 | 19 044 (30.5) | 204 (10.7) | 110 (5.8) | 88 (4.6) | 261 (13.7) | 61 (3.2) |
| Data missing | 543 (0.9) | 6 (11.0) | 3 (5.5) | 1 (1.8) | 13 (23.9) | 3 (5.5) |
| Country of birth | ||||||
| Nordicc | 51 127 (81.8) | 577 (11.3) | 318 (6.2) | 253 (4.9) | 710 (13.9) | 170 (3.3) |
| Non-Nordic | 11 342 (18.1) | 189 (16.7) | 119 (10.5) | 51 (4.5) | 185 (16.3) | 46 (4.1) |
| Data missing | 30 (0.0) | 0 (0.0) | 1 (33.3) | 0 (0.0) | 0 (0.0) | 0 (0.0) |
| Hypertensive disease | ||||||
| No | 53 537 (85.7) | 635 (11.9) | 387 (7.2) | 256 (4.8) | 753 (14.1) | 188 (3.5) |
| Chronic | 1090 (1.7) | 19 (17.4) | 7 (6.4) | 5 (4.6) | 26 (23.9) | 4 (3.7) |
| Pre-eclampsia | 7872 (12.6) | 112 (14.2) | 44 (5.6) | 43 (5.5) | 116 (14.7) | 24 (3.0) |
| Diabetic disease | ||||||
| No | 60 011 (96.0) | 736 (12.3) | 423 (7.1) | 291 (4.8) | 878 (14.6) | 211 (3.5) |
| Pre-gestational | 1368 (2.2) | 21 (15.4) | 8 (5.8) | 9 (6.6) | 6 (4.4) | 2 (1.5) |
| Gestational | 1120 (1.8) | 9 (8.0) | 7 (6.3) | 4 (3.6) | 11 (9.8) | 3 (2.7) |
| Preterm premature rupture of the membranes | ||||||
| No | 45 761 (73.2) | 598 (13.1) | 325 (7.1) | 260 (5.7) | 657 (14.4) | 168 (3.7) |
| Yes | 16 738 (26.8) | 168 (10.0) | 113 (6.8) | 44 (2.6) | 238 (14.2) | 48 (2.9) |
| Year of delivery | ||||||
| 1997–2000 | 15 166 (24.3) | 181 (11.9) | 140 (9.2) | 73 (4.8) | 148 (9.8) | 39 (2.6) |
| 2001–2004 | 16 404 (26.2) | 174 (10.6) | 100 (6.1) | 73 (4.5) | 221 (13.5) | 61 (3.7) |
| 2005–2008 | 17 347 (27.8) | 211 (12.2) | 107 (6.2) | 99 (5.7) | 293 (16.9) | 68 (3.9) |
| 2009–2011 | 13 582 (21.7) | 200 (14.7) | 91 (6.7) | 59 (4.3) | 233 (17.2) | 48 (3.5) |
| Infant characteristics | ||||||
| Gestational age (weeks) | ||||||
| 32–36 | 54 713 (87.5) | 278 (5.1) | 169 (3.1) | 204 (3.7) | 125 (2.3) | 19 (0.3) |
| <32 | 7786 (12.5) | 488 (62.7) | 269 (34.7) | 100 (12.8) | 770 (98.9) | 197 (25.3) |
| Birthweight-for-gestational age (percentile) | ||||||
| <3 | 5739 (9.2) | 108 (18.8) | 45 (7.8) | 32 (5.6) | 155 (27.0) | 36 (6.3) |
| 3 to <10 | 5054 (8.1) | 83 (16.4) | 43 (8.5) | 31 (6.1) | 102 (20.2) | 28 (5.5) |
| 10–90 | 44 379 (71.0) | 461 (10.4) | 265 (6.0) | 194 (4.4) | 599 (13.5) | 143 (3.2) |
| 90–97 | 3278 (5.2) | 16 (4.9) | 13 (4.0) | 14 (4.3) | 12 (3.7) | 3 (0.9) |
| ≥97 | 3262 (5.2) | 43 (13.2) | 31 (9.5) | 18 (5.5) | 11 (3.4) | 1 (0.3) |
| Data missing | 787 (1.3) | 55 (69.9) | 41 (52.2) | 15 (19.1) | 16 (20.3) | 5 (6.4) |
| Emergency deliveries | ||||||
| Nod | 50 294 (80.5) | 572 (11.4) | 344 (6.8) | 232 (4.6) | 704 (14.0) | 168 (3.3) |
| Yese | 12 205 (19.5) | 194 (15.9) | 94 (7.7) | 72 (5.9) | 191 (15.6) | 48 (3.9) |
| Sex | ||||||
| Male | 33 594 (53.8) | 441 (13.1) | 239 (7.1) | 179 (5.3) | 535 (15.9) | 135 (4.0) |
| Female | 28 905 (46.3) | 325 (11.2) | 199 (6.9) | 125 (4.3) | 360 (12.5) | 81 (2.8) |
IVH, intraventricular haemorrhage.
a
Rate is calculated as the number of cases per 1000 births.
b
Thirty-three infants had missing information on Apgar scores at 10 minutes.
c
Nordic countries include: Sweden, Denmark, Finland, Iceland and Norway.
d
No emergency deliveries include non-instrumental vaginal delivery (60.0%) and elective caesarean section (20.5%).
e
Emergency deliveries include instrumental vaginal delivery (4.4%) and emergency caesarean section (15.1%).