Can valproic acid exposure during pregnancy function as an environmental factor in autism?

PostedNovember 26, 2025

UpdatedNovember 26, 2025

ByMy Patient Advice

Author: Lucia Alvarez, MSc | Reviewed by: Dr. Clarissa Morton, PharmD

Yes, valproic acid exposure & autism are strongly linked, with prenatal exposure to this anti-epileptic drug recognised as a significant environmental factor that can elevate autism risk. Valproic acid, commonly used to treat epilepsy and bipolar disorder, has been shown in multiple studies to affect foetal brain development when taken during pregnancy.

Due to these concerns, regulatory bodies often advise against using valproic acid during pregnancy unless no safer alternatives are available. The effects are dose-dependent and most pronounced during the first trimester, when the developing nervous system is highly sensitive.

How Valproic Acid Exposure May Influence Autism Risk

Here are two ways valproic acid may increase autism risk through prenatal exposure:

Disruption of neural tube and early brain formation

Valproic acid has been associated with neural tube defects and may interfere with the formation of brain regions involved in communication and sensory processing, areas often impacted in autism.

Alteration of gene expression during development

Animal studies suggest valproic acid can modify how genes involved in brain development are expressed, potentially leading to long-term changes in cognitive and behavioural outcomes.

Understanding the risks of valproic acid exposure & autism supports the importance of medication reviews during pregnancy. Visit providers like Autism Detect for personal consultations and further guidance on screening and support.

For a deeper dive into the science, diagnosis, and full treatment landscape, read our complete guide to Environmental Factors.

Lucia Alvarez, MSc

Author

Lucia Alvarez is a clinical psychologist with a Master’s in Clinical Psychology and extensive experience providing evidence-based therapy and psychological assessment to children, adolescents, and adults. Skilled in CBT, DBT, and other therapeutic interventions, she has worked in hospital, community, and residential care settings. Her expertise includes grief counseling, anxiety management, and resilience-building, with a strong focus on creating safe, supportive environments to improve mental well-being.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the author's privacy.

Dr. Clarissa Morton, PharmD

Reviewer

Dr. Clarissa Morton is a licensed pharmacist with a Doctor of Pharmacy degree and experience across hospital, community, and industrial pharmacy. She has worked in emergency, outpatient, and inpatient pharmacy settings, providing patient counseling, dispensing medications, and ensuring regulatory compliance. Alongside her pharmacy expertise, she has worked as a Support Plan & Risk Assessment (SPRA) officer and in medical coding, applying knowledge of medical terminology, EMIS, and SystmOne software to deliver accurate, compliant healthcare documentation. Her skills span medication safety, regulatory standards, healthcare data management, and statistical reporting.

All qualifications and professional experience stated above are authentic and verified by our editorial team. However, pseudonym and image likeness are used to protect the reviewers's privacy.