How Cannabis Use During Pregnancy Affects the Placenta and Fetal Development
A comprehensive review finds that cannabis use disrupts the placental endocannabinoid system, impairing placental development and blood flow, with epidemiological evidence linking use to fetal growth restriction, preeclampsia, and potential transgenerational effects through DNA methylation changes.
Quick Facts
What This Study Found
Cannabis use interferes with the placental endocannabinoid system which regulates placental development and blood flow, with THC and CBD exerting effects via this system — and epidemiological data linking cannabis use to placental insufficiency, fetal growth restriction, preeclampsia, and potential epigenetic transgenerational effects.
Key Numbers
Reviews evidence on both maternal and paternal cannabis use effects; covers THC and CBD; documents links to fetal growth restriction, preeclampsia, placental insufficiency; highlights DNA methylation changes as transgenerational risk
How They Did This
Comprehensive narrative review synthesizing evidence on the placental endocannabinoid system, THC/CBD effects on placental function, cannabinoid pharmacokinetics during pregnancy, epidemiological data on birth outcomes, and emerging epigenetic evidence.
Why This Research Matters
With cannabis use during pregnancy increasing alongside legalization and perceived safety, this review compiles the growing evidence that cannabis directly interferes with placental function through a specific biological system.
The Bigger Picture
The presence of a functional endocannabinoid system in the placenta means that cannabis isn't just passing through — it's actively interfering with the biological machinery that supports fetal growth and development.
What This Study Doesn't Tell Us
Narrative review with potential selection bias; many included studies are preclinical; epidemiological data on pregnancy outcomes often has confounders (tobacco, alcohol co-use); epigenetic evidence is early-stage; dose-response relationships poorly characterized.
Questions This Raises
- ?Is there a safe level of cannabis use during pregnancy?
- ?How do different consumption methods (smoking vs. edibles vs. topicals) affect placental exposure?
- ?Could the epigenetic effects truly span generations?
Trust & Context
- Key Stat:
- Evidence Grade:
- Thorough narrative review integrating molecular, clinical, and epidemiological evidence, but relies partly on preclinical data and observational studies with potential confounding.
- Study Age:
- Published 2026; reviews the latest evidence including post-legalization epidemiological data.
- Original Title:
- Recreational Cannabis Use During Human Pregnancy: Its Effects on the Placenta and Endocannabinoid System.
- Published In:
- International journal of molecular sciences, 27(3) (2026)
- Authors:
- Harhangi, Madhavi S(2), Höfert, Lisa, Danser, A H Jan, Bijma, Hilmar H, Simons, Sinno H P, Reiss, Irwin K M, Baumann, Sven, Broekhuizen, Michelle
- Database ID:
- RTHC-08321
Evidence Hierarchy
Summarizes existing research on a topic.
What do these levels mean? →Frequently Asked Questions
Is it safe to use cannabis during pregnancy?
Current evidence suggests no — this review documents how both THC and CBD interfere with the placental endocannabinoid system that's essential for fetal development, with links to growth restriction and pregnancy complications.
Can a father's cannabis use affect the baby?
Emerging evidence reviewed here suggests that paternal cannabis use may affect sperm through epigenetic changes (DNA methylation), potentially influencing fetal development even without maternal cannabis exposure.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-08321APA
Harhangi, Madhavi S; Höfert, Lisa; Danser, A H Jan; Bijma, Hilmar H; Simons, Sinno H P; Reiss, Irwin K M; Baumann, Sven; Broekhuizen, Michelle. (2026). Recreational Cannabis Use During Human Pregnancy: Its Effects on the Placenta and Endocannabinoid System.. International journal of molecular sciences, 27(3). https://doi.org/10.3390/ijms27031398
MLA
Harhangi, Madhavi S, et al. "Recreational Cannabis Use During Human Pregnancy: Its Effects on the Placenta and Endocannabinoid System.." International journal of molecular sciences, 2026. https://doi.org/10.3390/ijms27031398
RethinkTHC
RethinkTHC Research Database. "Recreational Cannabis Use During Human Pregnancy: Its Effect..." RTHC-08321. Retrieved from https://rethinkthc.com/research/harhangi-2026-recreational-cannabis-use-during
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.