Table 1.

Characteristics of women who reported the use of thyroxin in early pregnancy.

Variable	With thyroxin	In population	OR	95% CI
Maternal age
<20	87	27828	0.31	0.20–0.38
20–24	1331	210254	0.58	0.55–0.62
25–29	5416	485407	1.00	Reference
30–34	9352	531265	1.53	1.48–1.55
35–39	6182	248516	2.10	2.02–2.19
40–44	1560	47018	2.80	2.64–2.98
≥45	93	2014	3.66	2.99–4.48
Parity
1	9247	687283	1.00	Reference
2	9250	562633	1.00	0.97–1.03
3	3696	310094	0.92	0.88–0.96
≥4	1846	92332	0.89	0.84–0.94
Smoking
Unknown	381	95377	—	—
None	22191	1316102	1.00	Reference
<10 cigs/day	1031	100330	0.87	0.72–0.81
≥10 cigs/day	428	40533	0.75	0.68–0.82
BMI
Unknown	1717	192912	—	—
<18.5	349	33624	0.87	0.78–0.97
18.5–24.9	12112	841302	1.00	Reference
25–29.9	6110	336114	1.22	1.18–1.25
30–34.9	2509	106013	1.58	1.52–1.65
≥35	1242	42377	1.93	1.82–2.05
Maternal diabetes	693	8028	5.28	5.01–5.78
Maternal use of thyreostatics	173	401	41.7	36.3–47.5
Maternal use of anticonvulsants	105	4385	1.38	1.14–1.68
Maternal use of antihypertensives	260	5506	2.20	1.94–2.49
Total number	24039	1552342	—	—

Odds ratio (OR) with 95% confidence intervals (95% CI) after adjustment for year of birth and maternal age, parity, smoking, and BMI. Bold figures mark statistical significance.