Table 3.

Number of events, crude event rates (per 1000), crude IRRs and adjusted HRs for the four outcomes and each of the AEDs studied—study population limited to women considered to be treated for epilepsy

	Events	Crude event rates	IRR	HR* (95% CI)	HR† (95% CI)
Neurodevelopmental disorders
Lamotrigine	32	4.2
Carbamazepine‡	1	1.5	0.4 (0.0 to 2.7)	0.2 (0.0 to 2.7)	0.2 (0.0 to 2.7)
Levetiracetam	8	3.7	0.9 (0.4 to 1.9)	0.8 (0.4 to 1.8)	0.8 (0.4 to 1.8)
Valproic acid	50	13.5	3.2 (2.0 to 5.0)	3.2 (2.0 to 4.9)	3.5 (2.3 to 5.4)
Pervasive developmental disorders
Lamotrigine	7	0.9
Carbamazepine‡	0	0.0	N/A	N/A	N/A
Levetiracetam	4	1.8	2.0 (0.6 to 6.8)	1.8 (0.5 to 6.6)	1.8 (0.5 to 6.6)
Valproic acid	17	4.5	4.9 (2.0 to 11.8)	4.9 (2.0 to 11.8)	4.7 (1.9 to 11.4)
Mental retardation
Lamotrigine	10	1.3
Carbamazepine‡	0	0.0	N/A	N/A	N/A
Levetiracetam	1	0.5	0.3 (0.0 to 2.7)	0.4 (0.1 to 2.9)	0.4 (0.1 to 2.9)
Valproic acid	15	4.0	3.0 (1.4 to 6.7)	3.1 (1.4 to 7.0)	4.0 (1.9 to 8.6)
Visits to a speech therapist
Lamotrigine	122	16.2
Carbamazepine‡	4	6.1	0.4 (0.1 to 1.0)	0.2 (0.1 to 0.7)	0.2 (0.1 to 0.7)
Levetiracetam	22	10.2	0.6 (0.4 to 1.0)	0.7 (0.4 to 1.1)	0.7 (0.4 to 1.1)
Valproic acid	93	25.1	1.6 (1.2 to 2.0)	1.4 (1.1 to 1.8)	1.5 (1.1 to 1.9)

Lines marked in bold correspond to HRs for which the 95% CI does not include 1.

*Adjusted for all covariates except hospitalisation for epilepsy during pregnancy.

†Adjusted for all covariates including hospitalisation for epilepsy during pregnancy.

‡No possible adjustment for the proxy for alcohol.

AED, antiepileptic drug; CI, confidence interval; HR, hazard ratio; IRR, incidence rate ratio; N/A, not applicable.