Clinical characteristics of the study mothers and newborn infants
| Variable |
Number (%) or mean [SD] | Range | n= |
| Maternal | |||
| Age (years) | 22.1 [3.9] | 15–40 | 577 |
| Height (cm) | 152.6 [6.1] | 136–172 | 563 |
| Weight (kg) | 49.4 [6.0] | 36–81 | 564 |
| Body mass index | 21.2 [2.2] | 15–31 | 563 |
| Haemoglobin (g/dl) | 11.0 [2.1] | 4–18.6 | 574 |
| Free T4 | 14.1 [3.6] | 5.5–34.3 | 559 |
| TSH | 3.05 [2.43] | 0.2–26.2 | 559 |
| <5 IU/l | 477 (85%) | ||
| >5 IU/l | 82 (15) | ||
| Pregnancy | |||
| Parity | 576 | ||
| Primiparate | 369 (64) | ||
| Multiparate | 207 (36) | ||
| Antenatal visits | 572 | ||
| None | 303 (53) | ||
| One/two | 78 (14) | ||
| More than two | 191 (33) | ||
| Gestational age | 576 | ||
| Term | 530 (92) | ||
| Post term | 46 (8) | ||
| Infant mean (SD) | |||
| Age at sampling (hrs) | 21.3 (12.7) | 0–55 | 578 |
| Sex | 577 | ||
| Male | 280 (49) | ||
| Female | 297 (51) | ||
| Birthweight | 577 | ||
| <2.5 kg | 183 (32) | ||
| >2.5 kg | 394 (68) | ||
| Birthweight (kg) | 2.69 [0.4] | 1.7–3.9 | 577 |
| Birth length (cm) | 47.2 [2.1] | 41–54 | 576 |
| Ponderal index | 2.5 [0.29] | 1.6–4.0 | |
| Head size (cm) | 32.6 [1.3] | 29–42 | 575 |
| Rectal temperature | 36.5 [0.76] | 33.9–39.2 | 574 |
| <36 | 114 (20) | ||
| >36 | 460 (80) | ||
| Infant haemoglobin (g/dl) | 17.5 (2.5) | 9–25 | 572 |
| <21 g/dl | 533 (93) | 572 | |
| >21 g/dl | 39 (7) | ||
| Free T4 | 29.4 [9.7] | 11–70 | 558 |
| Infant TSH | 23.9 [16.6] | 1.4–170 | 556 |
| Last feed | 577 | ||
| <3 hrs | 436 (76) | ||
| >3 hrs | 141 (24) | ||
| Apgar score | 576 | ||
| <7 at 5 min | 133 (23) | ||
| >7 at 5 min | 443 (73) | ||
| Environment | |||
| Ambient temperature | 578 | ||
| <25°C | 300 (52) | ||
| >25°C | 278 (48) | ||