A comprehensive meta-analysis published in JAMA Pediatrics has identified significant health risks associated with cannabis use during pregnancy, including higher rates of preterm birth, low birth weight, and infant mortality.
The review, led by Dr. Jamie Lo, an obstetrician and associate professor at Oregon Health & Science University, analyzed 51 studies encompassing over 21 million pregnancies globally. Key findings showed a 52% increased risk of preterm delivery, a 75% higher likelihood of low birth weight, and a 29% rise in perinatal mortality among cannabis users.
The study highlighted compromised placental function in pregnant individuals using cannabis, including reduced oxygen and blood flow, which may impair fetal lung development and growth. “The most critical finding is the elevated risk of perinatal mortality, whether during pregnancy or shortly after birth,” Dr. Lo stated. Despite these risks, data from the National Institute on Drug Abuse indicates cannabis use during pregnancy more than doubled between 2002 and 2017, particularly during the first trimester, often for nonmedical reasons.
Misconceptions about cannabis safety persist, fueled by its plant-based origin. Dr. Lo cautioned against this assumption, noting, “Opium, heroin, tobacco, and alcohol all derive from plants, yet none are considered safe during pregnancy.” Ethical barriers prevent randomized trials on expectant mothers, leaving researchers to rely on observational studies and self-reported data, which increasingly point to consistent adverse outcomes.
Using the GRADE system to evaluate evidence quality, the review upgraded prior “very low certainty” assessments to “low to moderate,” reflecting growing confidence in the findings. Brianna Moore, an epidemiologist at the Colorado School of Public Health, emphasized, “This analysis strengthens the connection between prenatal cannabis exposure and negative birth outcomes, even as research continues to evolve.”
The rise of cannabis legalization and shifting public perceptions have complicated health messaging. Many healthcare providers struggle to counsel patients due to conflicting studies, prompting efforts to develop updated, evidence-based guidelines. “Clinicians need clear, standardized resources to address this issue effectively,” Dr. Lo explained.
Beyond pregnancy, cannabis has been associated with broader health concerns, including cardiovascular events, cognitive decline, and mental health disorders. Heavy use is also linked to severe nausea episodes and increased emergency hospital visits. Experts unanimously advise avoiding THC, cannabis’s psychoactive component, during pregnancy. “No form of THC exposure is risk-free for fetal development,” Dr. Lo stressed.
As legalization expands, the study underscores the urgency of bridging gaps in public health education. While evidence mounts, challenges such as affordability, regulatory inconsistencies, and persistent myths about cannabis safety remain hurdles.
The findings reinforce calls for targeted campaigns to inform pregnant individuals, ensuring decisions are grounded in emerging science rather than anecdotal beliefs. This evolving landscape highlights the need for interdisciplinary collaboration to safeguard maternal and infant health amid changing societal norm
