The Risks of Cannabis Use During Pregnancy: A Systematic Review Update

The implications of cannabis consumption during pregnancy are increasingly concerning, according to an updated systematic review published in JAMA Pediatrics. This comprehensive study reveals significant risks associated with cannabis use, including increased chances of preterm birth, low birth weight, and infant mortality.

Research Insights from Oregon Health & Science University

The study, conducted by researchers at Oregon Health & Science University (OHSU), highlights the rising trend of cannabis use among pregnant women. Lead author Jamie Lo, M.D., M.C.R., who specializes in maternal-fetal medicine, has observed a concerning pattern in her practice: “Patients are coming to me in their prenatal visits saying, ‘I quit smoking and drinking, but is it safe to still use cannabis?'” This signifies a critical need for clear guidance and information regarding cannabis use during pregnancy.

The Growing Perception of Safety

Despite the potential risks, many expectant mothers perceive cannabis as a safe alternative, especially when they aim to mitigate symptoms like nausea, insomnia, and pain associated with pregnancy. Unlike alcohol and nicotine, whose use during pregnancy has declined, cannabis consumption is on the rise, raising alarms among healthcare professionals.

Methodology of the Updated Review

The updated systematic review examined data from 51 observational studies encompassing over 21.1 million individuals. Notably, eight new studies were included since the last review, which significantly enhanced the evidence quality from “very low-to-low” to “moderate.” This updated evaluation underscores the increased likelihood of adverse outcomes related to low birth weight, preterm birth, and smaller body sizes for gestational age.

Impact on Newborn Mortality

While the review pointed to increased odds of newborn mortality, the certainty surrounding this finding remains low. Researchers adapted their approach, expanding the review to include a greater proportion of observational studies focused solely on cannabis use without the confounding effects of nicotine consumption.

Links to Animal Studies

The findings of this human study are consistent with previous research conducted on nonhuman primates exposed to THC, the primary psychoactive component of cannabis. These animal studies utilized advanced prenatal imaging techniques, such as standard ultrasounds and MRI scans, demonstrating significant negative impacts on placental function including compromised blood flow and oxygen availability, as well as reduced amniotic fluid volumes.

The Role of the Placenta

Dr. Lo emphasizes the critical role that placental health plays in fetal development: “When the placenta isn’t functioning well, it can affect the baby’s development and growth.” This insight underlines the necessity for medical professionals to stress the importance of prenatal health in relation to substance use.

Legal Status and Recommendations

Despite the risks associated with cannabis use during pregnancy, it remains a Schedule 1 substance under federal law, although states like Oregon have legalized its use for both medicinal and recreational purposes. Dr. Lo recommends a harm-reduction strategy for patients who find it challenging to abstain from cannabis. She advises these patients to minimize their intake and frequency of use to mitigate risks to both prenatal and infant health.

“Even using less can mitigate the risk,” Lo insists. “Abstinence is ideal, but it’s not realistic for many patients.” This pragmatic approach is crucial as it aligns medical advice with real-world experiences of many expectant mothers.

Conclusion

The findings from this systematic review serve as a critical reminder of the risks associated with cannabis use during pregnancy. As more research unfolds, it becomes increasingly important for healthcare providers to inform patients and guide them toward safer choices for their health and the health of their babies.