Neonatal rats given CBD on days 1, 3, and 5 of life showed decreased dendritic complexity in brain neurons and females developed spatial memory deficits in adulthood, raising questions about CBD safety in the earliest stages of life.
Neonatologists, OB-GYNs counseling pregnant/breastfeeding patients, and researchers studying cannabinoid developmental neurotoxicology.
What the researchers found
Neonatal CBD exposure (50 mg/kg on postnatal days 1, 3, 5) caused decreased dendritic length and spine density in both cortical and hippocampal neurons in both sexes, with reduced dendritic arborization on Sholl analysis. Females (but not males) showed spatial memory deficits in the Barnes maze. No anxiety changes in either sex.
Why it matters
CBD is increasingly considered for neonatal conditions like seizures, and maternal CBD use during pregnancy could expose newborns through breast milk. This study provides concerning evidence that early-life CBD exposure may permanently alter brain architecture and sex-specifically impair memory.
The numbers in context
50 mg/kg CBD intraperitoneally on postnatal days 1, 3, and 5. Overall decrease in dendritic length and spine density (apical and basal) in cortex and hippocampus. Reduced dendritic intersections on Sholl analysis. Females showed spatial memory deficit; males did not. No anxiety changes in either sex.
How the study worked
Male and female neonatal Sprague Dawley rats received CBD (50 mg/kg IP) on postnatal days 1, 3, and 5. In early adulthood, rats were tested on Barnes maze (spatial memory), open field, and elevated plus maze (anxiety). Golgi-Cox staining assessed neuronal morphology in cortex and hippocampus.
What this study cannot tell us
High-dose intraperitoneal CBD in rats — human neonatal exposure would be much lower. Only three dosing days — different schedules may have different effects. Golgi-Cox staining provides morphological but not functional detail. Rat brain development timeline differs from humans.
How to read the evidence
Preclinical study with behavioral and morphological endpoints, but high doses and intraperitoneal route limit translation to human neonatal exposure.
When this study was published
Published 2025.
The bigger picture
As more parents use CBD during pregnancy and breastfeeding, and as neonatal CBD applications are explored, this study sounds an important caution. The sex-specific memory deficit adds to growing evidence that cannabinoids affect male and female brains differently during development.
Questions still open
- Does prenatal CBD exposure through maternal use produce similar brain changes? Would lower doses still affect neuronal morphology? Why are females more vulnerable to the memory effects? Could these findings influence guidelines for breastfeeding mothers who use CBD?
Common questions
Is CBD safe during pregnancy or breastfeeding?
Why were females affected more than males?
Read the original research
Neonatal Cannabidiol Exposure Impairs Spatial Memory and Disrupts Neuronal Dendritic Morphology in Young Adult Rats.
Cannabis and cannabinoid research, 10(1), e145-e155
Citation
Wadhwa, Meetu; Chinn, Gregory A; Sasaki Russell, Jennifer M; Hellman, Judith; Sall, Jeffrey W. (2025). Neonatal Cannabidiol Exposure Impairs Spatial Memory and Disrupts Neuronal Dendritic Morphology in Young Adult Rats.. Cannabis and cannabinoid research, 10(1), e145-e155. https://doi.org/10.1089/can.2024.0010
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