Rat pups exposed to vaporized THC in the womb, particularly at lower doses, showed decreased attention and object exploration in adolescence, marking the first study of its kind using vaporized delivery.
Researchers studying prenatal cannabis effects and pregnant individuals who vape cannabis.
Low-dose vaporized THC produced more attention deficits than high-dose in offspring
What the researchers found
Rats exposed to low-dose vaporized THC (10 mg) during pregnancy showed significantly decreased object exploration in both novel object recognition and object-based attention tests, indicating reduced attention. High-dose THC (40 mg) showed some effects on learning patterns but not ultimate performance. Females showed lower attention scores than males in object-based attention.
Why it matters
This is the first study using vaporized THC for prenatal exposure, which better mimics how humans actually use cannabis. The finding that lower doses produced more pronounced attention deficits is counterintuitive and important for understanding risk at typical use levels.
The numbers in context
THC doses: 10 mg and 40 mg vaporized; low-dose group: significantly decreased object exploration; females lower than males in object-based attention; testing in early and late adolescence
How the study worked
Pregnant rats were exposed to vaporized THC (10 mg or 40 mg) daily from gestational day 2 until labor. Offspring received standard or high-fat diets and were tested in early and late adolescence using novel object recognition, Morris Water Maze, and object-based attention tests.
What this study cannot tell us
Animal study with vaporized delivery that may not perfectly replicate human vaping. Two dose levels only. Behavioral tests have limited translational validity. Cannot determine if effects persist into adulthood beyond adolescence.
How to read the evidence
Novel approach using vaporized delivery, but animal study with only two dose levels and limited translational validity.
When this study was published
Published in 2024.
The bigger picture
As vaping becomes the dominant cannabis consumption method, understanding prenatal exposure through this route is critical. The paradoxical dose effect (lower dose worse for attention) may reflect different mechanisms at different exposure levels.
Questions still open
- Why did lower THC doses produce more attention deficits than higher doses?
- Would these attention deficits persist into adulthood or resolve?
Common questions
Can vaping cannabis during pregnancy affect the baby's brain?
Why were lower doses worse?
Read the original research
Vaporized Δ9-tetrahydrocannabinol exposure in utero has negative effects on attention in a dose- and sex-dependent manner.
Pharmacology, biochemistry, and behavior, 242, 173808
Citation
Penman, Samantha L; Roeder, Nicole M; Wang, Jia; Richardson, Brittany J; Freeman-Striegel, Lily; Krayevsky, Alexis; Eiden, Rina D; Chakraborty, Saptarshi; Thanos, Panayotis K. (2024). Vaporized Δ9-tetrahydrocannabinol exposure in utero has negative effects on attention in a dose- and sex-dependent manner.. Pharmacology, biochemistry, and behavior, 242, 173808. https://doi.org/10.1016/j.pbb.2024.173808
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