Women who use CBD for pregnancy-related mental and physical discomfort could be putting their offspring at risk, according to a new study by researchers in the U.S. and Canada that underpins warnings by major global health agencies.
“These findings have significant implications for understanding the effects of CBD on fetal life, changing the general idea that CBD is a universally safe compound, and revealing the need for additional studies on the effect of prenatal CBD exposure,” said Daniella Iezzi, one of the researchers.
The authors note that a separate International Cannabis Policy Study showed pregnant women use CBD products at a higher rate than the non-pregnant female population. Roughly one in five pregnant women queried in that study – 20.4% – reported using CBD in the past 30 days for anxiety and depression, pain, headache, and morning sickness, while usage among the non-pregnant female sample was at a rate of 11.3%.
By challenging the belief that CBD is safe, the new study bolsters warnings by health officials on both sides of the Atlantic who have repeatedly raised concerns regarding the hemp compound’s potentially harmful effects on pregnant women and fetuses, young children, the elderly, and the liver and male reproductive system. The U.S. Food & Drug Administration, the European Food Safety Authority (EFSA) and the UK’s Food Standards Agency have all issued such warnings and called for further research.
‘Profound’ changes in brain
The rodent-based primary research of both male and female mice born to mothers injected with CBD showed changes in two parts of the insular cortex (IC), a part of the brain that integrates the body’s response to emotions and decisions. Sometimes referred to as the brain’s “integration hub,” the insular cortex is responsible for processing emotional and social signals as well as the perception of pain.
The offspring mice were tested once they reached adulthood. The researchers placed the mice in a new environment, and their social interactions were monitored with software that uses a depth-sensing camera and machine learning to analyze the behavior of groups of mice in real-time.
“Our results reveal that prenatal exposure to CBD profoundly changes the functionality of neurons in the insular cortex,” according to Iezzi.
“We saw differences according to sex and also according to IC sub-regions. In particular, pyramidal neurons in the pIC (posterior IC) lose their cellular identity following prenatal exposure to CBD and no longer behave like typical pIC neurons.
“This could have negative consequences on specific functions of the pIC. . . . A loss of pIC differentiation following prenatal exposure to CBD can have a considerable impact on the ability to understand and react properly to the environment,” Iezzi said.
Psychiatric disorders
IC disfunction increases the risk of psychiatric disorders, including anxiety, addiction, depression and schizophrenia, Iezzi added.
The results suggested that CBD altered specific mice behaviors and was sex-dependent.
“We found a number of behavioral changes among the mice exposed to CBD,” said another researcher on the project, Alba Caceres Rodriguez, a PhD student at INSERM Aix-Marseille University, a French public research organization that focuses on human health.
“CBD-exposed females tended to move around their new environment more compared to females that didn’t receive CBD during gestation. Furthermore, compared to control mice, both male and female mice treated with CBD established more physical contacts with each other.”
‘Public health priority’
Previous research found that CBD passes through the placenta, can reach the brain of rodents and human embryos, and show up in breast milk. “Therefore, it’s a public health priority to understand the impact of CBD on the developing nervous system as we don’t yet know the consequences of CBD exposure to the brain during development,” Caceres Rodriguez said.
While the mice used in the research were given a controlled dose of CBD, pregnant humans may be more likely to use CBD intermittently throughout their pregnancy and take considerably larger doses than those given to the mice, the study observes.
The research, which has yet to be peer-reviewed, was published in Obstetrics & Gynecology, a journal by Dutch medical publisher Wolters Kluwer Health, Inc. It was carried out by researchers from the Department of Psychiatry at the Colorado School of Medicine, and the School of Public Health and Health Systems, University of Waterloo, Ontario, Canada. The paper was presented at the Federation of European Neuroscience Societies (FENS) Forum 2024, which runs through Saturday in Vienna.
Other studies have questioned CBD’s efficacy as a treatment for pain.
