Advancing a Pre-Clinical Model of Full-Term Prenatal Exposure to Vaporized Δ9-Tetrahydrocannabinol
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Updated: Oct 9, 2026
Preclinical Model of Prenatal Delta-9-Tetrahydrocannabinol Exposure to Assess Its Impact on Neurodevelopmental Outcomes
Published on: February 28, 2025
Bryan W Jenkins1, Catherine F Moore1, Praachi Tiwari1
1Division of Behavioral Biology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Introduction:
Use of cannabinoid vape products during pregnancy is a major public health concern. 9-tetrahydrocannabinol (THC), the main psychoactive constituent in cannabis, is rapidly absorbed after inhalation and transferred to the fetal brain. We developed a novel model of prenatal cannabinoid exposure (PCE) comprising THC vapor exposure across the human-equivalent full-term prenatal period in rats. This study examined gestational/parturitional outcomes and the distribution and metabolism of THC in maternal and filial blood and brains using this model.
Materials And Methods:
Pregnant female Sprague-Dawley rats were exposed to THC (200 mg/mL, n = 13) or vehicle (100% propylene glycol, n = 8) vapor daily during gestation until postnatal day (PD) 10 (i.e., human-equivalent full-term). Pups were exposed directly in the postnatal period. Gestational/parturitional assessments included dam food intake, dam and pup body weights, total gestation days, litter size, and sex ratio. Subsets of THC-exposed dams and pups were sampled immediately postvapor on gestational day (GD) 20 (n = 4 dams, 24 pups) or PD 10 (n = 2 dams, 33 pups) to quantify THC and its metabolites (11-hydroxy-Δ9-tetrahydrocannabinol [11-OH-THC], and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol [THCCOOH]) concentrations in the brain (dams and pups) and plasma (dams).
Results:
THC decreased dam food intake and total gestation days compared to controls. THC concentrations in dam plasma and brain were 14.8 ± 47.8 ng/mL and 80.5 ± 38.6 ng/g on GD 20 and 68.9 ± 25.0 ng/mL and 125.0 ± 4.2 ng/g on PD 10. Birth weights were not different between THC-exposed offspring and controls, but postnatal weights were decreased. On GD 20, fetal brain THC, 11-OH-THC, and THCCOOH concentrations were 12 ± 5%, 118 ± 7%, and 75 ± 34% of maternal plasma. On PD 10, pup brain THC and 11-OH-THC concentrations were 29.6 ± 8.5 and 9.8 ± 2.1 ng/g. THCCOOH was not detected in PD 10 pup brain.
Discussion:
THC readily transferred from dams to pup brains during gestation in our full-term vapor exposure model. High THC and 11-OH-THC concentrations were detected in pup brains at both timepoints. This novel model is a valuable tool to investigate long-term effects of full-term PCE on offspring brain development and behavior.
