Rat offspring exposed to a cannabinoid agonist during fetal development showed reduced ovarian reserve in adulthood, an effect mediated through CB1 receptors and reversed by prenatal CB1 blockade.
Reproductive health researchers, people interested in prenatal cannabis exposure effects
Ovarian reserve reduction appeared at adulthood (PND90) but not at birth (PND6)
What the researchers found
Young adult rats (PND90) exposed prenatally to the CB1/CB2 agonist WIN55212 had decreased ovarian reserve, an effect reversed by prenatal CB1 receptor blockade with SR141716. Conversely, prenatal CB1 blockade alone resulted in higher ovarian reserve counts. Prenatal cannabinoid modulation also altered mRNA levels of endocannabinoid system enzymes and ovarian reserve regulation genes. No effect was seen at PND6.
Why it matters
Ovarian reserve is established during fetal life and determines reproductive lifespan. If prenatal cannabinoid exposure affects this process, it could have implications for the future fertility of daughters born to cannabis-using mothers.
The numbers in context
WIN55212: 0.5 mg/kg; SR141716: 3 mg/kg; THC: 5 mg/kg. Ovarian reserve decrease appeared at PND90 but not PND6, indicating a delayed effect. CB1 blockade reversed the decrease.
How the study worked
Four groups of pregnant rats received WIN55212 (0.5 mg/kg), SR141716 (3 mg/kg), THC (5 mg/kg), or vehicle. Ovarian reserve was histologically assessed in female offspring at postnatal days 6, 40, and 90. RT-PCR measured gene expression changes.
What this study cannot tell us
Animal model with synthetic cannabinoid agonist rather than cannabis; doses and routes may not reflect human exposure patterns; ovarian reserve counts are a proxy for fertility, not a direct fertility measure.
How to read the evidence
Single animal study using synthetic cannabinoids; ovarian reserve is an indirect fertility measure.
When this study was published
Published in 2020.
The bigger picture
This adds to evidence that the endocannabinoid system plays a role in ovarian development and that disrupting it during fetal life could have delayed reproductive consequences.
Questions still open
- Does prenatal cannabis use in humans affect daughters' ovarian reserve? Why did the effect appear only in adulthood and not at birth?
Common questions
Could cannabis use during pregnancy affect a daughter's fertility?
Why did the effect only show up in adulthood?
Read the original research
Prenatal cannabinoid exposure alters the ovarian reserve in adult offspring of rats.
Archives of toxicology, 94(12), 4131-4141
Citation
Castel, Pierre; Barbier, Magalie; Poumerol, Elodie; Mandon-Pépin, Béatrice; Tassistro, Virginie; Lepidi, Hubert; Pelissier-Alicot, Anne-Laure; Manzoni, Olivier J; Courbiere, Blandine. (2020). Prenatal cannabinoid exposure alters the ovarian reserve in adult offspring of rats.. Archives of toxicology, 94(12), 4131-4141. https://doi.org/10.1007/s00204-020-02877-1
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