Table 2.
Presence of congenital malformations in infants whose mothers reported the use of thyroxin in early pregnancy (n = 23 259) and in all infants born (n = 1 567 736).
| Malformation | Number with thyroxin | Total number | OR/RR | 95% CI |
|---|---|---|---|---|
| Any relatively severe malformation | 730 | 48 012 | 1.06 | 0.98–1.14 |
| Any chromosome anomaly | 59 | 2927 | 1.18 | 0.91–1.53 |
| Down syndrome | 42 | 1911 | 1.25 | 0.92–1.69 |
| Excluding chromosome anomalies | ||||
| Neural tube defects | 7 | 725 | 0.81 | 0.33–1.68# |
| Other CNS malformations | 22 | 1118 | 1.60 | 1.05–2.44 |
| Severe eye malformations | 6 | 577 | 0.84 | 0.34–1.74# |
| Severe ear malformations | 4 | 277 | 1.03 | 0.28–2.63# |
| Choanal atresia | 7 | 161 | 3.14 | 1.26–6.47# |
| Orofacial clefts | 40 | 2740 | 1.01 | 0.79–1.38 |
| Cardiovascular defects | 245 | 15891 | 1.05 | 0.92–1.19 |
| Septal defects | 171 | 10974 | 1.04 | 0.94–1.28 |
| Oesophageal atresia | 9 | 444 | 1.38 | 0.63–2.62# |
| Small gut atresia | 3 | 390 | 0.54 | 0.11–1.58# |
| Anal atresia | 16 | 588 | 1.85 | 1.00–1.85# |
| Pyloric stenosis | 11 | 1095 | 0.74 | 0.41–1.33 |
| Abdominal wall defects | 5 | 412 | 1.28 | 0.42–2.98# |
| Diaphragmatic hernia | 8 | 365 | 1.56 | 0.67–3.08# |
| Hypospadias | 70 | 4508 | 1.05 | 0.82–1.32 |
| Severe kidney malformations | 16 | 873 | 1.32 | 0.81–2.17 |
| Pes equinovarus | 28 | 2115 | 0.93 | 0.64–1.35 |
| Poly- or syndactyly | 38 | 3065 | 0.93 | 0.60–1.14 |
| Limb reduction defects | 13 | 826 | 1.13 | 0.65–1.96 |
| Craniosynostosis | 10 | 857 | 0.79 | 0.42–1.48 |
Odds ratio (OR) or risk ratio (RR marked#) with 95% confidence intervals (95% CI). Bold text marks statistical significance.