Table 3. Baseline characteristics and perinatal outcomes for non-overlapping populations classified as small for gestational age by WHO fetal charts or GROW charts.
| Characteristic or outcome | AGAall (n = 16,470) | SGAWHOAGAGROW (n = 396) | SGAGROWAGAWHO (n = 1,180) |
|---|---|---|---|
| Baseline characteristics | |||
| Maternal | |||
| Age, mean (SD) | 31.0 (5.7) | 29.7 (5.5) | 31.6 (5.8) |
| Height, mean (SD) | 163 (15.9) | 156 (6.4) | 166 (6.5) |
| BMI, mean (SD) | 25.5 (6.0) | 21.7 (3.6) | 28.6 (6.7) |
| Indigenous, n (%) | 227 (1.4) | 3 (0.8) | 29 (2.5) |
| Nulliparous, n (%) | 8,203 (49.8) | 316 (79.4) | 343 (29.1) |
| Infant | |||
| Birthweight, median (IQR) | 2,570 (2,289.3–2,790) | 2,184 (1,924–2,300) | 2,230 (1,866–2,410) |
| Gestation at delivery, median (IQR) | 251 (241–255) | 250 (348–253) | 249 (235–256) |
| Male, n (%) | 8,940 (54.3) | 214 (53.8) | 626 (53.1) |
| Obstetric and perinatal outcomes | |||
| Perinatal mortality | |||
| Total | 375 (2.3) | 12 (3.0) | 54 (4.6) |
| Ref | 1.33 (0.76–2.34, p = 0.32) | 2.00 (1.52–2.66, p < 0.001) | |
| Stillbirth | 275 (1.7) | 9 (2.3) | 44 (3.7) |
| Ref | 1.36 (0.71–2.62, p = 0.36) | 2.23 (1.63–3.05, p < 0.001) | |
| Neonatal death | 100 (0.61) | 3 (0.76) | 10 (0.84) |
| Ref | 1.25 (0.40–3.92, p = 0.70) | 1.40 (0.73–2.66, p = 0.31) | |
| Apgar score | |||
| Ap5 < 4 | 360 (2.2) | 10 (2.5) | 50 (4.2) |
| Ref | 1.16 (0.62–2.15, p = 0.65) | 1.94 (1.45–2.59, p < 0.001) | |
| Ap5 < 7 | 1,105 (6.7) | 37 (9.3) | 116 (9.8) |
| Ref | 1.39 (1.02–1.90, p = 0.04) | 1.47 (1.22–1.76, p < 0.001) | |
| NICU admission | 1,618 (9.8) | 46 (11.6) | 174 (14.7) |
| Ref | 1.18 (0.90–1.56, p = 0.24) | 1.50 (1.30–1.73, p < 0.001) | |
| Suspicion of poor growth | |||
| Operative delivery for fetal distress | 1,901 (11.5) | 81 (20.5) | 159 (13.5) |
| Ref | 1.77 (1.45–2.16, p < 0.001) | 1.17 (1.00–1.36, p = 0.05) | |
| Induction or operative birth for suspected poor fetal growth | 342 (2.1) | 41 (10.4) | 115 (9.7) |
| Ref | 4.99 (3.66–6.79, p < 0.001) | 4.69 (3.83–5.75, p < 0.001) | |
| Cesarean section | |||
| Total | 6,465 (39.3) | 188 (47.5) | 583 (49.4) |
| 1.21 (1.09–1.34, p < 0.001) | 1.26 (1.18–1.34, p < 0.001) | ||
| Planned | Ref | 58 (14.6) | 176 (14.9) |
| 1,874 (11.4) | 1.29 (1.01–1.64, p = 0.04) | 1.31 (1.14–1.51, p < 0.001 | |
| Emergency | Ref | 130 (32.8) | 407 (34.5) |
| 4,591 (27.9) | 1.18 (1.02–1.36, p = 0.03) | 1.24 (1.14–1.34, p < 0.001) | |
Outcome data presented as number (%) and relative risk ratio (95% CI, p-value).
AGAall, appropriate size for gestational age (>10th centile and <90th centile) by all intrauterine charts; Ap5, 5-minute Apgar score; GROW, Gestation Related Optimal Weight; NICU, neonatal intensive care unit; SGAWHOAGAGROW, small for gestational age (<10th centile) by WHO fetal charts but appropriate size for gestational age (>10th centile) by GROW customised charts; SGAGROWAGAWHO, small for gestational age (<10th centile) by GROW customised charts but appropriate size for gestational age (>10th centile) by WHO fetal charts.