Table 4. Univariable and multivariable comparisons of clinical and ultrasound risk factors for Normotensive-SGA by customised birthweight centiles.
| Training Cohort | |||||
| N = 3735 | N = 3541 | ||||
| Risk Factors | NT SGA | Non NT SGA | Univariable Odds Ratio (95% CI) † | Multivariable Odds Ratio (95% CI) | Multivariable Odds Ratio (95% CI) †† |
| N = 313 | N = 3422 | ||||
| 15 week data | AUC = 0.66 | AUC = 0.71 | |||
| Maternal birthweight (grams)* | 3166 (551) | 3323 (558) | |||
| <3000 | 105 (36%) | 782 (24%) | 2.05 (1.51 to 2.78) | 2.01 (1.49 to 2.72) | 1.88 (1.37 to 2.58) |
| 3000–3499 | 110 (37%) | 1259 (39%) | 1.33 (0.99 to 1.80) | 1.38 (1.03 to 1.85) | 1.37 (1.01 to 1.85) |
| ≥3500 | 79 (27%) | 1204 (37%) | 1.0 | 1.00 | 1.00 |
| Currently attending university | 19 (6%) | 89 (3%) | 2.42 (1.46 to 4.03) | 2.52 (1.49 to 4.25) | 2.50 (1.43 to 4.37) |
| Currently smoking | 65 (21%) | 347 (10%) | 2.32 (1.73 to 3.12) | 2.29 (1.69 to 3.09) | 2.22 (1.62 to 3.04) |
| Vigorous exercise ≥1 x/day | 10 (3%) | 31 (0.9%) | 3.63 (1.76 to 7.48) | 3.97 (1.87 to 8.41) | 3.91 (1.6 to 9.07) |
| Recreational walking ≥4 x/week | 45 (15%) | 725 (21%) | 0.63 (0.45 to 0.87) | 0.61 (0.44 to 0.85) | 0.58 (0.41 to 0.83) |
| Rhesus negative blood group | 25 (8%) | 528 (15%) | 0.48 (0.31 to 0.72) | 0.48 (0.31 to 0.73) | 0.51 (0.33 to 0.78) |
| Random glucose per unit increase | 5.2 (0.9) | 5.3 (1.0) | 0.86 (0.76 to 0.97) | 0.85 (0.75 to 0.96) | 0.84 (0.73 to 0.96) |
| 20 week scan data †† | N = 298 | N = 3277 | |||
| Head circumference z score <10th centile** | 50 (17%) | 283 (9%) | 2.13 (1.53 to 2.95) | 1.70 (1.19 to 2.43) | |
| Abdominal circumference z score <10th centile*** | 50 (17%) | 292 (9%) | 2.06 (1.49 to 2.86) | 1.78 (1.25 to 2.54) | |
| Average uterine resistance index | 0.61 (0.10) | 0.57 (0.10) | |||
| <0.5 | 40 (13%) | 861 (26%) | 1.0 | 1.0 | |
| 0.5 to 0.59 | 94 (32%) | 1276 (39%) | 1.59 (1.08 to 2.32) | 1.56 (1.06 to 2.30) | |
| 0.6 to 0.69 | 110 (37%) | 793 (24%) | 2.99 (2.05 to 4.34 ) | 2.73 (1.86 to 4.00) | |
| 0.7 to 1.0 | 54 (18%) | 347 (11%) | 3.35 (2.19 to 5.14) | 3.21 (2.07 to 4.97) | |
Data are mean (SD) number (%) as appropriate, italics indicate variable is protective.
*
missing data numbers for woman’s birthweight (SGA n = 19, no SGA 178 missing.
**
missing data numbers for head circumference z score <10th centile (SGA n = 2, no SGA n = 23 missing).
***
missing data numbers for abdominal circumference z score <10th centile (SGA n = 1, no SGA n = 12 missing).
†
Unimputed data was used for univariate analyses.
††
Unimputed ultrasound data was added to the multivariable models derived from 15 week imputed data.
NT SGA = birth of an SGA infant where the mother did not develop hypertension.
Non NT SGA = all women in the remainder of the cohort who did not have Normotensive-SGA pregnancies.