Cannabis and Pregnancy: What the Latest Research Says — and Why the Message Isn't Getting Through
Cannabis use during pregnancy has increased significantly as legalization spreads. The research on risks is clearer than ever — but many pregnant people aren't getting the message.
Dr. Elena Rodriguez
Medical Science Editor, Cannabis Dispensary
Cannabis use during pregnancy has increased dramatically as legalization has spread. A 2024 CDC survey found that 7% of pregnant people reported using cannabis in the past month — up from 3.4% in 2002. This increase is occurring despite growing evidence of risks to fetal development.
What the Research Shows
The evidence on cannabis and pregnancy has strengthened significantly in recent years. Key findings:
Fetal growth restriction: Multiple studies have found that prenatal cannabis exposure is associated with lower birth weight and fetal growth restriction. A 2023 meta-analysis of 24 studies found a 5–10% reduction in birth weight associated with prenatal cannabis use.
Neurodevelopmental effects: The ABCD (Adolescent Brain Cognitive Development) study, the largest longitudinal study of child brain development in the US, has found that children exposed to cannabis prenatally show differences in brain structure and cognitive function at ages 9–10. These differences include reduced attention, increased anxiety, and lower academic performance.
Preterm birth: Several studies have found associations between prenatal cannabis use and preterm birth, though the evidence is less consistent than for growth restriction.
Why Use Is Increasing
Many pregnant people use cannabis for nausea and vomiting of pregnancy (NVP) — morning sickness. With limited safe pharmacological options for severe NVP, some turn to cannabis. Others use it for anxiety or pain. The perception that "natural" means safe is common.
The Communication Gap
Despite clear medical guidance against cannabis use during pregnancy, many pregnant people are not receiving the message. A 2024 survey found that 34% of pregnant cannabis users believed it was safe, and 22% said their healthcare provider had not discussed cannabis with them.
The Bottom Line
No safe level of cannabis use during pregnancy has been established. The American College of Obstetricians and Gynecologists, the American Academy of Pediatrics, and the CDC all recommend against cannabis use during pregnancy and breastfeeding. Healthcare providers should proactively discuss cannabis with all pregnant patients.