Table 1. Study population characteristics at 15±1 weeks’ and pregnancy outcome.
| Training Cohort | Validation Cohort | |||||
| SGA | Not-SGA | P value | SGA | Not-SGA | P value | |
| N = 422 | N = 3313 | N = 211 | N = 1660 | |||
| Maternal Characteristics | ||||||
| Maternal age (y) | 28.6 (5.8) | 28.6 (5.4) | 0.94 | 28.5 (5.7) | 28.9 (5.5) | 0.40 |
| Ethnicity | 0.30 | 0.83 | ||||
| White | 373 (88%) | 2994 (91%) | 191 (91%) | 1487 (90%) | ||
| Maori or Pacific Islander* | 10 (2%) | 61 (2%) | 3 (1%) | 39 (2%) | ||
| Asian or Indian | 23 (6%) | 179 (5%) | 12 (6%) | 88 (5%) | ||
| Other† | 16 (4%) | 79 (2%) | 5 (2%) | 46 (3%) | ||
| Primigravid | 312 (74%) | 2568 (78%) | 0.09 | 154 (73%) | 1285 (77%) | 0.15 |
| Single | 48 (11%) | 304 (9%) | 0.15 | 31 (15%) | 154 (9%) | 0.009 |
| No paid employment | 75 (18%) | 465 (14%) | 0.04 | 43 (20%) | 243 (15%) | 0.03 |
| <12 years education | 168 (40%) | 1223 (37%) | 0.25 | 90 (43%) | 635 (38%) | 0.22 |
| Smoking status | <0.0001 | <0.0001 | ||||
| Non smoker | 286 (68%) | 2538 (77%) | 142 (67%) | 1283 (77%) | ||
| Ceased smoking before15 wks | 55 (13%) | 444 (13%) | 29 (14%) | 225 (14%) | ||
| Current smoker | 81 (19%) | 331 (10%) | 40 (19%) | 152 (9%) | ||
| BMI category | 0.02 | 0.06 | ||||
| <20.0 | 36 (8%) | 221 (7%) | 14 (7%) | 131 (8%) | ||
| 20.0–24.9 | 189 (45%) | 1702 (51%) | 87 (41%) | 816 (49%) | ||
| 25.0–29.9 | 117 (28%) | 908 (27%) | 69 (33%) | 478 (29%) | ||
| ≥30 | 80 (19%) | 482 (15%) | 41 (19%) | 235 (14%) | ||
| Maternal birthweight (g) | 3163 (540) | 3329 (559) | 0.0001 | 3184(499) | 3319 (523) | <0.001 |
| N = 395 | N = 3144 | N = 197 | N = 1583 | |||
| Systolic BP (mmHg) | 108 (11) | 107 (10) | 0.004 | 109 (11) | 107 (11) | 0.01 |
| Diastolic BP (mmHg) | 66 (9) | 65 (8) | 0.01 | 67 (8) | 65 (8) | 0.002 |
| Pregnancy Outcome | ||||||
| Hypertensive Pregnancy‡ | 109 (26%) | 409 (12%) | <0.0001 | 59 (28%) | 183 (11%) | <0.0001 |
| Birthweight (g) | 2641 (557) | 3500 (516) | <0.0001 | 2627 (614) | 3512 (483) | <0.0001 |
| Gestational age at delivery (wks) | 39.0 (3.4) | 39.7 (2.0) | <0.0001 | 38.5 (3.6) | 39.8 (1.8) | <0.0001 |
| Customised birthweight centile | 4.7 (3) | 53.0 (26) | <0.0001 | 4.7 (3) | 53.3 (26) | <0.0001 |
| Total preterm births (<37 wks) | 54 (13%) | 177 (5%) | <0.0001 | 40 (19%) | 80 (5%) | <0.0001 |
| Admitted to neonatal unit* | 82 (19%) | 340 (10%) | <0.0001 | 61 (29%) | 164 (10%) | <0.0001 |
| Perinatal deaths | 7 (1.7%) | 15 (0.5%) | <0.0001 | 5 (2%) | 1 (0.1%) | <0.0001 |
Results expressed as N (%) or mean (SD) as appropriate;
*
includes 44 Maori and 27 Pacific Islanders in the training and 27 Maori and 15 Pacific Islanders in the validation set;
†
includes 15 Australian Aborigines in the training and 8 in the validation set.
‡
Hypertensive pregnancy defined as preeclampsia, gestational hypertension or mild chronic hypertension.