Table 4 Cases of major congenital malformations by monotherapy drug group

Drug	MCMs in PCFA group (n (%) (95% CI))	MCMs in no PCFA group (n (%) (95% CI))
CBZ	14 (2.4) (1.4–4.0)	11 (2.3) (1.3–4.0)
LTG	16 (2.5) (1.5–4.0)	7 (1.9) (0.9–3.9)
VPA	21 (5.3) (3.5–8.0)	18 (4.3) (2.8–6.8)

CBZ, carbamazepine; LTG, lamotrigine; MCM, major congenital malformation; PCFA, preconceptual folic acid; VPA, sodium valproate.