Table 2.
Characteristics of pregnancies classified according to OGTT diagnosis
| Characteristic | All pregnancies | OGTT not done | NICE-negative IADPSG-negative | NICE-positive IADPSG-positive | NICE-negative IAD-positive | NICE-positive IAD-negative (NICE-only 2 h) | IADPSG-only 0 h | IADPSG-only 1 h |
|---|---|---|---|---|---|---|---|---|
| N | 25,543 | 21,695 | 2,406 | 794 | 387 | 261 | 167 | 288 |
| Maternal age, yearsa | 30.7 (30.6, 30.8) |
30.5 (30.4, 30.6) |
31.4 (31.2, 31.6)*** |
32.7 (32.4, 33.1)*** |
32.6 (32.1, 33.1)*** |
32.1 (31.5, 32.7)*** |
32.7 (31.9, 33.5)*** |
32.6 (32.0, 33.2)*** |
| Maternal usual BMI, kg/m2a | 24.7 (24.6, 24.8) |
24.4 (24.3, 24.4) |
26.0 (25.7, 26.2)*** |
27.6 (27.1, 28.1)*** |
27.4 (26.8, 28.1)*** |
25.5 (24.8, 26.2)*** |
29.0 (27.9, 30.1)*** |
27.2 (26.5, 27.9)*** |
| Maternal ethnicityc, d | *** | ** | ** | |||||
| White | 22,762 (89.3) | 19,406 (89.4) | 2,151 (89.4) | 641 (80.7) | 336 (86.8) | 228 (87.4) | 144 (86.2) | 246 (85.4) |
| Black | 423 (1.7) | 376 (1.7) | 28 (1.2) | 10 (1.3) | 4 (1.0) | 5 (1.9) | 1 (0.6) | 3 (1.0) |
| Asian | 1,353 (5.3) | 1,077 (5.0) | 126 (5.2) | 92 (11.6) | 36 (9.3) | 22 (8.4) | 18 (10.8) | 31 (10.8) |
| Other | 947 (3.7) | 791 (3.6) | 89 (3.7) | 50 (6.3) | 11 (2.8) | 6 (2.3) | 4 (2.4) | 8 (2.8) |
| Maternal smokingb | 2,416 (9.5) | 2,150 (9.9) | 177 (7.4)*** | 47 (5.9)*** | 27 (7.0) | 15 (5.7) | 11 (6.6) | 21 (7.3) |
| Primiparousb | 9,895 (38.7) | 8,389 (38.7) | 941 (39.1) | 317 (39.9) | 141 (36.4) | 107 (41.0) | 57 (34.1) | 103 (35.8) |
| Estimated gestational age at delivery, weeksa | 39.2 (39.1, 39.2) | 39.2 (39.1, 39.2) | 39.3 (39.3, 39.4)*** | 38.8 (38.6,38.9)*** | 39.1 (38.9, 39.2) | 38.9 (38.7, 39.1) | 39.1 (38.8, 39.4) | 39.1 (38.8, 39.3) |
| Birthweight, ga | 3,381.2 (3,373.8, 3,388.7) | 3,360.7 (3,352.6, 3,368.8) | 3,496.6 (3,473.9, 3,519.3)*** | 3,487.1 (3,446.2, 3,528.0)*** | 3,612.1 (3,551.1, 3,673.1)*** | 3,360.7 (3,294.7, 3,426.8) | 3,711.1 (3,619.0, 3,803.2)*** | 3,574.2 (3,503.4, 3,645.0)*** |
| Mode of delivery | ||||||||
| SVD | 15,321 (60.0) | 13,405 (61.8) | 1,264 (52.5) | 341 (42.9) | 190 (49.1) | 121 (46.4) | 74 (44.3) | 147 (51.0) |
| Emergency CS | 3,937 (15.4) | 3,132 (14.4) | 473 (19.7) | 190 (23.9) | 94 (24.3) | 48 (18.4) | 44 (26.3) | 68 (23.6) |
| Elective CS | 2,858 (11.2) | 2,254 (10.4) | 342 (14.2) | 157 (19.8) | 53 (13.7) | 52 (19.9) | 29 (17.4) | 35 (12.2) |
| Instrumental | 3,319 (13.0) | 2,802 (12.9) | 324 (13.5) | 104 (13.1) | 50 (12.9) | 39 (14.9) | 20 (12.0) | 38 (13.2) |
| Other/unknown | 108 (0.4) | 102 (0.5) | 3 (0.1) | 2 (0.3) | 0 (0.0) | 1 (0.4) | 0 (0.0) | 0 (0.0) |
| Complications | ||||||||
| LGA | 3,010 (12.2) | 2,264 (10.4) | 406 (16.9) | 195 (24.6) | 115 (29.7) | 30 (11.5) | 63 (37.7) | 75 (26.0) |
| Macrosomia | 3,097 (12.1) | 2,427 (11.2) | 403 (16.8) | 131 (16.5) | 112 (28.9) | 24 (9.2) | 61 (36.5) | 77 (26.7) |
| SGA | 2,956 (12.0) | 2,619 (12.5) | 224 (9.6) | 57 (7.3) | 24 (6.4) | 32 (12.6) | 8 (4.9) | 19 (6.8) |
| Stillbirth | 85 (0.3) | 77 (0.4) | 5 (0.2) | 2 (0.3) | 1 (0.3) | 0 (0.0) | 0 (0.0) | 1 (0.3) |
| Preterm | 1,726 (6.8) | 1,492 (6.9) | 127 (5.3) | 57 (7.2) | 29 (7.5) | 21 (8.0) | 11 (6.6) | 21 (7.3) |
| Pre-eclampsia | 1,454 (5.7) | 1,147 (5.3) | 174 (7.2) | 70 (8.8) | 39 (10.1) | 24 (9.2) | 16 (9.6) | 32 (11.1) |
| Polyhydramnios | 283 (1.1) | 122 (0.6) | 106 (4.4) | 32 (4.0) | 15 (3.9) | 8 (3.1) | 5 (3.0) | 13 (4.5) |
| APH | 530 (2.1) | 443 (2.0) | 57 (2.4) | 17 (2.1) | 6 (1.6) | 7 (2.7) | 3 (1.8) | 5 (1.7) |
| PPH | 411 (1.6) | 344 (1.6) | 48 (2.0) | 14 (1.8) | 4 (1.0) | 1 (0.4) | 1 (0.6) | 4 (1.4) |
| 1 min Apgar score <7 | 1,537 (6.0) | 1,297 (6.0) | 141 (5.9) | 50 (6.3) | 34 (8.8) | 15 (5.7) | 18 (10.8) | 25 (8.7) |
| 5 min Apgar score <7 | 211 (0.8) | 186 (0.9) | 11 (0.5) | 9 (1.1) | 4 (1.0) | 1 (0.4) | 1 (0.6) | 4 (1.4) |
| Infant admission to NICU | 1,725 (6.8) | 1,488 (6.9) | 143 (5.9) | 53 (6.7) | 22 (5.7) | 19 (7.3) | 10 (6.0) | 16 (5.6) |
| Treatment offered for GDM | 1,017 (4.0) | 0 (0.0) | 0 (0.0) | 756 (95.2) | 0 (0.0) | 261 (100.0) | 0 (0.0) | 0 (0.0) |
Data are n (%) or mean (95% CI)
aLinear or blogistic regression or cFisher’s exact test used to compare GDM classification groups with ‘OGTT not done’ group
dEthnicity: significance testing indicates changes in ethnic composition between groups
**p ≤ 0.01; ***p ≤ 0.001
APH, antepartum haemorrhage; PPH, postpartum haemorrhage; SVD, spontaneous vertex delivery