Available evidence indicated that cannabis use during pregnancy and breastfeeding may adversely affect fetal brain development, with potential impacts on neuropsychiatric, behavioral, and executive functioning that could persist into adulthood.
Read this if you are pregnant or breastfeeding and use cannabis, or want to understand the evidence on prenatal cannabis exposure.
Cannabis crosses the placenta and enters breast milk, exposing the developing brain
What the researchers found
This review summarized knowledge about cannabis use in pregnancy, including pharmacology, placental transfer, and developmental effects. Key findings included that cannabis compounds cross the placenta and enter breast milk, exposing the developing fetus and nursing infant to psychoactive substances.
The evidence suggested adverse effects on neurodevelopment, particularly during critical brain growth periods in fetal development and adolescent maturation. Reported effects included impacts on neuropsychiatric, behavioral, and executive functioning that could influence future adult productivity.
However, the authors noted that reported rates of cannabis use in pregnancy are likely significantly underestimated, and much of the available literature had focused on other drugs (opioids, stimulants), leaving cannabis effects less well characterized.
Why it matters
Cannabis is one of the most widely used drugs among women of childbearing age, and use during pregnancy appears to be increasing. The limited but concerning evidence of developmental effects highlights the need for more research and clearer clinical guidance.
The numbers in context
No specific prevalence statistics were reported, but the review noted that rates of prenatal cannabis exposure are likely significantly underestimated.
How the study worked
Review of published articles, governmental guidelines, and data on cannabis use patterns in pregnant women, pharmacology of psychoactive compounds, placental and fetal transfer, and effects on pregnancy, the newborn, and child development.
What this study cannot tell us
Limited quality data on cannabis use specifically during pregnancy. Difficulty separating cannabis effects from tobacco, alcohol, and socioeconomic confounders. Very limited data on cannabis effects during breastfeeding. Most studies focused on THC rather than whole-plant exposure.
How to read the evidence
Narrative review synthesizing limited available evidence on prenatal cannabis exposure.
When this study was published
Published in 2014. Research on cannabis in pregnancy has continued to develop.
The bigger picture
As cannabis becomes legal in more jurisdictions, the perception that it is safe may lead to increased use during pregnancy. The developing fetal brain is the organ most vulnerable to cannabinoid effects, given the endocannabinoid system's role in guiding brain development.
Questions still open
- What level of cannabis exposure during pregnancy is harmful? Are effects on child development permanent? Does CBD have different effects than THC during pregnancy? How long do cannabinoids persist in breast milk?
Common questions
Does cannabis use during pregnancy affect the baby?
Is cannabis safe while breastfeeding?
Read the original research
Cannabis, the pregnant woman and her child: weeding out the myths.
Journal of perinatology : official journal of the California Perinatal Association, 34(6), 417-24
Citation
Jaques, S C; Kingsbury, A; Henshcke, P; Chomchai, C; Clews, S; Falconer, J; Abdel-Latif, M E; Feller, J M; Oei, J L. (2014). Cannabis, the pregnant woman and her child: weeding out the myths.. Journal of perinatology : official journal of the California Perinatal Association, 34(6), 417-24. https://doi.org/10.1038/jp.2013.180
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