Anatomical, behavioral, and cognitive teratogenicity associated with valproic acid: a systematic review

Recent guidance from UK health authorities strongly cautions against the use of valproic acid (VPA) in persons under 55 because of reevaluated risk of teratogenicity.

To summarize the extant literature documenting VPA-associated anatomical, behavioral, and cognitive teratogenicity.

Pubmed, Medline, Cochrane Library, PsychInfo, Embase, Scopus, Web of Science, and Google Scholar were searched in accordance with PRISMA guidelines. Collected data covered study design, participant characteristics, anatomical, behavioral, or cognitive effects, and folic acid outcomes.

122 studies were identified meeting inclusion comprised of studies evaluating anatomical (n = 67), behavioral (n = 28), and cognitive (n = 47) teratogenicity. Twenty studies were identified reporting on the risk mitigation effects of folic acid supplementation. Prenatal VPA exposure is associated with anatomical teratogenicity including major congenital malformations (odds ratio [OR] 2.47-9.30; p < 0.005). Behavioral teratogenicity including autism (OR 1.70-4.38), impaired motor development (OR 7.0), and ADHD (OR 1.39) are also significantly associated with VPA exposure. VPA was associated with intellectual disability and low IQ (hazard ratio [HR] 2.4-4.48, verbal intelligence: Spearman's ρ = -0.436, respectively). Teratogenic effects were dose-dependent across all domains and were significant when compared with controls and other antiepileptic drugs (eg, carbamazepine, lamotrigine, and levetiracetam). Folic acid supplementation does not significantly reduce the hazard associated with VPA.

VPA is significantly associated with anatomical, behavioral, and cognitive teratogenicity. Folic acid supplementation does not abrogate the risk of teratogenicity associated with VPA exposure. Available evidence supports recommendations to reduce VPA exposure in women of reproductive age.