Table 2.

Odds ratios for the risk of congenital heart defects.

Thyroxine	Unadjusted models		Adjusted modelsa
	Odds ratio (95% CI)	P value	Odds ratio (95% CI)	P value
FT4 (pmol/L)	1.04 (1.02–1.07)	0.001	1.04 (1.01–1.07)	0.003
TT4 (ng/ml)	1.01 (0.94–1.08)	0.85	1.01 (0.95–1.08)	0.78
FTT4P (%)	2.59 (1.35–4.97)	0.004	2.41 (1.27–4.59)	0.007

Abbreviations: FT4, free thyroxine; TT4, total thyroxine; FTT4P, free-to-total thyroxine proportion; and 95% CI, 95% confidence interval. ^aAdjusted factors included maternal age (<25, 25–34, or ≥35), residence (local or nonlocal), parity (nulliparous or pluriparous), assisted conception (yes or no), gestational diabetes (yes or no), preeclampsia (yes or no), and fetal sex (male or female).