Table 4

Number of events, crude event rates (per 1000), crude IRRs and adjusted HRs for the four outcomes according to the dose of valproic acid dispensed during pregnancy—main analysis and sensitivity analysis restricted to women considered to be treated for epilepsy

		Events	Crude event rates	Main analysis		Women with epilepsy
		Events	Crude event rates	IRR	HR* (95% CI)	IRR	HR* (95% CI)	HR† (95% CI)
Neurodevelopmental disorders	<700 mg	7	6.3	1.3 (0.6 to 2.8)	1.3 (0.6 to 2.8)	1.5 (0.7 to 3.4)	1.6 (0.7 to 3.6)	1.6 (0.7 to 3.6)
	700–1500 mg	23	11.5	2.3 (1.4 to 3.8)	2.1 (1.3 to 3.5)	2.7 (1.6 to 4.6)	2.5 (1.5 to 4.3)	2.7 (1.6 to 4.6)
	≥1500 mg	20	33.5	6.8 (4.1 to 11.5)	7.0 (4.3 to 11.5)	7.9 (4.5 to 13.8)	8.6 (5.1 to 14.5)	8.7 (5.2 to 14.6)
Pervasive developmental disorders	<700 mg	2	1.8	1.7 (0.4 to 7.6)	2.2 (0.5 to 8.5)	1.9 (0.4 to 9.3)	2.9 (0.7 to 11.6)	2.7 (0.7 to 11.4)
	700–1500 mg	7	3.4	3.3 (1.3 to 8.4)	2.7 (1.0 to 7.1)	3.7 (1.3 to 10.7)	3.1 (1.1 to 9.0)	3.0 (1.0 to 8.9)
	≥1500 mg	8	12.8	12.2 (4.9 to 30.4)	14.7 (6.2 to 34.7)	14.0 (5.1 to 38.5)	17.0 (6.5 to 44.6)	15.4 (5.7 to 41.1)
Mental retardation	<700 mg	5	4.4	3.1 (1.1 to 8.5)	1.5 (0.4 to 5.9)	3.4 (1.2 to 9.9)	1.8 (0.4 to 7.0)	1.6 (0.4 to 6.7)
	700–1500 mg	5	2.5	1.7 (0.6 to 4.7)	1.8 (0.7 to 4.9)	1.9 (0.6 to 5.5)	1.9 (0.7 to 5.7)	2.6 (1.0 to 6.7)
	≥1500 mg	5	7.9	5.5 (2.0 to 15.2)	7.3 (3.0 to 17.7)	6.0 (2.1 to 17.6)	7.1 (2.7 to 18.7)	8.4 (3.4 to 20.4)
Visits to a speech therapist	<700 mg	13	11.6	0.8 (0.4 to 1.3)	0.6 (0.3 to 1.0)	0.7 (0.4 to 1.3)	0.6 (0.3 to 1.0)	0.5 (0.3 to 0.9)
	700–1500 mg	54	27.3	1.8 (1.3 to 2.5)	1.6 (1.2 to 2.1)	1.7 (1.2 to 2.3)	1.5 (1.1 to 2.0)	1.5 (1.1 to 2.1)
	≥1500 mg	26	43.4	2.9 (1.9 to 4.3)	2.6 (1.7 to 4.0)	2.7 (1.8 to 4.1)	2.6 (1.7 to 4.0)	2.7 (1.8 to 4.1)

*Adjusted for all covariates except hospitalisation for epilepsy during pregnancy.
†Adjusted for all covariates including hospitalisation for epilepsy during pregnancy.
CI, confidence interval; HR, hazard ratio; IRR, incidence rate ratio.