Table 4.

 Adjusted* odds ratios (95% confidence intervals) for exposure to carbamazepine monotherapy compared with no antiepileptic drug, valproic acid, and other antiepileptic drugs, with two control groups: non-chromosomal malformations (control 1) and chromosomal malformations (control 2)

Malformation subgroup (No of cases)	Carbamazepine	No antiepileptic drug			Valproic acid monotherapy†			Other monotherapy‡
		Control 1	Control 2		Control 1	Control 2		Control 1	Control 2
Spina bifida (n=2048)	8	2.6 (1.2 to 5.3)	4.2 (1.5 to 11.2)		0.2 (0.1 to 0.6)	0.3 (0.1 to 1.2)		1.1 (0.4 to 3.6)	1.4 (0.3 to 6.6)
Total anomalous pulmonary venous return (n=132)	0	—	—		—	—		—	—
Cleft lip (with or without palate) (n=3544)	1	0.2 (0.0 to 1.3)	0.2 (0.0 to 1.7)		0.3 (0.0 to 2.6)	0.2 (0.0 to 2.7)		0.1 (0.0 to 0.6)	0.0 (0.0 to 0.5)
Diaphragmatic hernia (n=755)	1	0.9 (0.1 to 6.6)	1.0 (0.1 to 8.5)		0.5 (0.0 to 4.5)	0.4 (0.0 to 5.8)		0.2 (0.0 to 2.2)	0.2 (0.0 to 2.5)
Hypospadias, boys only (n=5393)	6	0.7 (0.3 to 1.6)	0.5 (0.2 to 1.8)		0.2 (0.1 to 0.5)	0.1 (0.0 to 0.7)		0.8 (0.2 to 2.9)	0.4 (0.1 to 4.0)

*Adjusted for year of birth and maternal age. Odds ratios for comparison with no antiepileptic drug additionally adjusted for reporting centre.

†Excluding malformations associated with valproic acid exposure. Cases exposed to valproic acid: spina bifida (27), total anomalous pulmonary venous return (2), cleft lip (3), diaphragmatic hernia (2), hypospadias (32).

‡Excluding valproic acid. Cases exposed to other antiepileptic drug monotherapy: spina bifida (5), total anomalous pulmonary venous return (0), cleft lip (10), diaphragmatic hernia (3), hypospadias (5).