THC altered trophoblast differentiation in mouse placental stem cells through the CB1 receptor, reducing syncytiotrophoblast markers and shifting development toward other cell types, suggesting a mechanism for THC-induced placental pathology.
Reproductive biologists, obstetricians, pregnancy researchers
THC shifted placental cells away from nutrient-exchange function via CB1
What the researchers found
THC exposure at physiologically relevant levels significantly altered trophoblast stem cell differentiation in a CB1-dependent manner, reducing expression of syncytiotrophoblast (SynT) markers while driving differentiation toward junctional zone/trophoblast giant cell pathways. CB1 knockout cells showed no SynT marker expression. Higher non-physiological THC concentrations (15 microM) could induce SynT markers even without CB1.
Why it matters
This study identifies a specific mechanism by which THC could harm placental development: diverting trophoblast differentiation away from the cell type that forms the maternal-fetal nutrient exchange interface. This could explain growth restriction observed in cannabis-exposed pregnancies.
The numbers in context
THC tested at physiologically relevant serum levels; CB1 expressed in all maternal blood-facing trophoblast cells; SynT markers reduced; junctional zone markers increased; 15 microM THC (non-physiological) overrode CB1 knockout.
How the study worked
In vitro study using mouse trophoblast stem cells, including CB1 knockout (Cnr1KO) cells. Assessed THC effects on differentiation markers at physiologically relevant and elevated concentrations. Examined CB1 expression across placental cell types.
What this study cannot tell us
Mouse model may not fully reflect human placental biology. In vitro differentiation does not capture the full complexity of placental development in vivo. Dose-response at physiological vs. non-physiological concentrations suggests threshold effects that need further characterization.
How to read the evidence
Well-designed mechanistic mouse study with CB1 knockout controls, but in vitro and species-specific limitations.
When this study was published
2025 publication
The bigger picture
Cannabis use during pregnancy is increasing. This study provides mechanistic evidence for how THC might cause the placental pathology and growth restriction seen in epidemiological studies, strengthening the biological plausibility of those associations.
Questions still open
- Does this trophoblast differentiation shift occur in human placental tissue?
- At what THC exposure level does placental harm begin in human pregnancies?
Common questions
How does THC affect placental development?
Is it safe to use cannabis during pregnancy?
Read the original research
Delta 9-Tetrahydrocannabinol Signaling Through Cannabinoid Receptor 1 Alters Trophoblast Differentiation.
Stem cells and development, 34(21-22), 441-455
Citation
Koven, Jessica L; Natale, Bryony V; Hardy, Daniel B; Natale, David R C. (2025). Delta 9-Tetrahydrocannabinol Signaling Through Cannabinoid Receptor 1 Alters Trophoblast Differentiation.. Stem cells and development, 34(21-22), 441-455. https://doi.org/10.1177/15473287251392544
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