Smoked vs. Injected Cannabis During Rat Pregnancy Produced Very Different Effects in Offspring
Rat offspring exposed to smoked cannabis during gestation showed different and generally milder behavioral changes than those exposed to injected THC or CBD, suggesting the method of exposure matters significantly.
Quick Facts
What This Study Found
Injected THC and CBD had more severe impacts on maternal and litter health and produced distinct behavioral patterns compared to smoked cannabis. High-THC smoke decreased prepulse inhibition (a measure of sensory filtering) in adolescent female offspring, which normalized by adulthood. Injected THC increased exploratory behavior in both sexes.
Key Numbers
High-THC smoke decreased PPI and MK-801-induced locomotor activity in adolescent females (normalized by adulthood); injected THC increased exploratory behavior in both sexes; injected CBD impaired PPI in both sexes in adulthood; all gestational exposures impaired odor-based recognition tasks regardless of treatment type
How They Did This
Pregnant rats were exposed to high-THC or high-CBD cannabis smoke or received THC or CBD injections during gestation. Offspring were tested on prepulse inhibition, locomotor activity, social interaction, object recognition, and attention tasks during adolescence and adulthood.
Why This Research Matters
Most preclinical research on prenatal cannabis exposure uses injected THC at high doses, but most pregnant humans who use cannabis smoke it. This study shows the route of exposure produces meaningfully different offspring outcomes, suggesting prior injection-based research may not reflect real-world risk.
The Bigger Picture
The cannabis and pregnancy research field has largely relied on injected THC studies. This head-to-head comparison suggests those studies may overestimate some risks while missing others specific to smoked exposure, calling for more research using realistic exposure methods.
What This Study Doesn't Tell Us
Rat model may not translate to humans, specific cannabis strains and doses used, cannot isolate combustion byproducts from cannabinoid effects in smoke group, limited behavioral battery
Questions This Raises
- ?Do the milder effects of smoked cannabis reflect lower cannabinoid delivery or different pharmacokinetics?
- ?Would vaporized cannabis produce yet another pattern?
- ?Do the adolescent effects that normalized by adulthood truly resolve or simply become subtler?
Trust & Context
- Key Stat:
- Injected THC had more severe effects on offspring than smoked cannabis across multiple behavioral measures
- Evidence Grade:
- Single animal study comparing exposure routes; novel design but limited to one strain of rats and specific cannabis varieties
- Study Age:
- Published 2025
- Original Title:
- Differential effects of gestational Cannabis smoke and phytocannabinoid injections on male and female rat offspring behavior.
- Published In:
- Progress in neuro-psychopharmacology & biological psychiatry, 136, 111241 (2025)
- Authors:
- Black, Tallan(6), Barnard, Ilne L(4), Baccetto, Sarah L(3), Greba, Quentin, Orvold, Spencer N, Austin-Scott, Faith V L, Sanfuego, Genre B, Onofrychuk, Timothy J, Glass, Aiden E, Andres, Rachel M, Macfarlane, Leah M, Adrian, Jesse C, Heidt, Ashton L, McElroy, Dan L, Laprairie, Robert B, Howland, John G
- Database ID:
- RTHC-06075
Evidence Hierarchy
Tests effects in animals (usually mice or rats), not humans.
What do these levels mean? →Frequently Asked Questions
Does it matter whether prenatal cannabis exposure is smoked or injected in research?
Yes. This rat study found injected THC and CBD produced more severe maternal effects and different behavioral outcomes in offspring compared to smoked cannabis, suggesting exposure method significantly affects results.
Did prenatal cannabis exposure cause lasting behavioral problems in offspring?
Some effects (like impaired sensory filtering from THC smoke) appeared in adolescence but normalized by adulthood. However, all exposure types impaired odor-based recognition tasks regardless of age.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-06075APA
Black, Tallan; Barnard, Ilne L; Baccetto, Sarah L; Greba, Quentin; Orvold, Spencer N; Austin-Scott, Faith V L; Sanfuego, Genre B; Onofrychuk, Timothy J; Glass, Aiden E; Andres, Rachel M; Macfarlane, Leah M; Adrian, Jesse C; Heidt, Ashton L; McElroy, Dan L; Laprairie, Robert B; Howland, John G. (2025). Differential effects of gestational Cannabis smoke and phytocannabinoid injections on male and female rat offspring behavior.. Progress in neuro-psychopharmacology & biological psychiatry, 136, 111241. https://doi.org/10.1016/j.pnpbp.2024.111241
MLA
Black, Tallan, et al. "Differential effects of gestational Cannabis smoke and phytocannabinoid injections on male and female rat offspring behavior.." Progress in neuro-psychopharmacology & biological psychiatry, 2025. https://doi.org/10.1016/j.pnpbp.2024.111241
RethinkTHC
RethinkTHC Research Database. "Differential effects of gestational Cannabis smoke and phyto..." RTHC-06075. Retrieved from https://rethinkthc.com/research/black-2025-differential-effects-of-gestational
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.