Table 2 Pregnancy and birth outcomes for all participants and according to maternal iodine-to-creatinine ratio
| Â | Iodine-to-creatinine ratio (cohort split into thirds) | |||
|---|---|---|---|---|
All participants, n = 6637 | Lower third (< 67 μg/g), n = 2213 | Middle third (67 to 105 μg/g), n = 2212 | Higher third (> 105 μg/g), n = 2212 | |
Size at birth | ||||
 Birthweight centile, mean (SD) | 43.6 (28.5) | 42.0 (28.1) | 43.7 (28.9) | 45.2 (28.6) |
 Birthweight (g), mean (SD) | 3245 (549) | 3217 (542) | 3247 (568) | 3271 (535) |
 Small for gestational age (< 10th centile), n (%) | 880 (13) | 311 (14) | 298 (13) | 271 (12) |
 Low birthweight (< 2.5 kg), n (%) | 466 (7) | 167 (8) | 161 (7) | 138 (6) |
 Head circumference at birth (mm), mean (SD) | 343 (16) | 343 (15) | 343 (17) | 344 (15) |
APGAR score (out of 10), median (IQR) | ||||
 1 min | 8.5 (1.4) | 8.5 (1.3) | 8.4 (1.4) | 8.5 (1.1) |
 5 min | 9.0 (0.7) | 9.0 (0.7) | 9.0 (0.7) | 9.1 (0.7) |
Ultrasound scan (34 weeks) estimations, mean (SD) | ||||
 Head circumference (mm) | 315 (9) | 314 (9) | 315 (9) | 315 (9) |
 Biparietal diameter (mm) | 8.5 (0.3) | 8.5 (0.3) | 8.5 (0.3) | 8.5 (0.3) |
 Femur length (mm) | 65 (2) | 65 (2) | 65 (2) | 65 (2) |
 Abdominal circumference (mm) | 295 (14) | 294 (14) | 295 (14) | 296 (14) |
 Estimated weight (g) | 2237 (237) | 2228 (244) | 2234 (228) | 2248 (240) |
Preterm (< 37 weeks), n (%) | 354 (5) | 114 (5) | 134 (6) | 106 (5) |
Stillbirth, n (%) | 37 (0.6) | 12 (0.5) | 14 (0.6) | 11 (0.5) |
Congenital anomalies, n (%) | ||||
 All | 353 (5.3) | 123 (5.6) | 127 (5.7) | 103 (4.7) |
 Nervous system | 125 (1.9) | 39 (1.8) | 44 (2.0) | 42 (1.9) |