In lab-grown placental cells, cannabis smoke extract disrupted cell development and mitochondrial function in ways that pure THC did not, and blocking the cannabinoid receptor only rescued the THC effects, not the smoke effects.
Obstetric care providers, prenatal health educators, reproductive toxicology researchers
CB1 receptor blockade rescued THC effects but not cannabis smoke extract effects on placental cells
What the researchers found
Cannabis smoke extract (CaSE) reduced markers of placental cell maturation (hCG protein and syncytin-1 gene expression) and caused dose-dependent mitochondrial dysfunction. Lower concentrations elevated reactive oxygen species while higher concentrations disrupted mitochondrial respiration. Blocking the CB1 receptor rescued the effects of pure THC but not of cannabis smoke extract.
Why it matters
Smoking remains the most common way pregnant people consume cannabis, yet most research focuses on THC alone. This study demonstrates that combustion byproducts create additional harm to placental cells that cannot be blocked by targeting cannabinoid receptors.
The numbers in context
CaSE induced CYP1A1 expression (a combustion byproduct marker) but THC did not. Lower CaSE concentrations (1%, 2.5%) elevated reactive oxygen species. Higher concentrations (5%, 10%) disrupted mitochondrial respiration. CB1 antagonism rescued THC effects but not CaSE effects.
How the study worked
In vitro study using human trophoblast cells exposed to cannabis smoke extract versus pure THC. Researchers measured markers of cell differentiation, reactive oxygen species, mitochondrial membrane potential and respiration, antioxidant gene expression, and the effect of CB1 receptor blockade.
What this study cannot tell us
In vitro study using cell cultures, not a living placenta. Cannabis smoke extract preparation may not perfectly replicate real-world smoking. Single cell type studied. No comparison with vaporized or edible cannabis.
How to read the evidence
Well-designed in vitro study with appropriate controls comparing smoke extract to pure THC, but cell culture findings may not directly translate to pregnancy outcomes.
When this study was published
2026 publication
The bigger picture
Public health messaging about cannabis in pregnancy typically focuses on THC. This research suggests how cannabis is consumed may matter as much as whether it is consumed, with smoking introducing combustion-related toxicity that pure cannabinoid exposure does not.
Questions still open
- Would vaporized or edible cannabis avoid the placental damage seen with smoke? Do these in vitro findings translate to measurable differences in placental function during pregnancy?
Common questions
Is smoking cannabis worse than edibles during pregnancy?
Does this mean THC is safe for pregnancy?
Read the original research
Cannabis smoke extract disrupts trophoblast differentiation and causes mitochondrial dysfunction beyond the effects of Δ9-THC alone.
Scientific reports, 16(1), 6253
Citation
Monaco, Cristina; Minhas, Mahek; Podinic, Tina; Nederveen, Joshua P; Lucas, Amica-Mariae; Tomy, Thane; Tomy, Gregg T; Holloway, Alison C; Raha, Sandeep. (2026). Cannabis smoke extract disrupts trophoblast differentiation and causes mitochondrial dysfunction beyond the effects of Δ9-THC alone.. Scientific reports, 16(1), 6253. https://doi.org/10.1038/s41598-026-36939-8
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