Fetal exposure to CBD linked to altered pain sensitivity and cognitive function

New research sheds light on the potential impact of cannabidiol (CBD) consumption during pregnancy on the development of the offspring. A study conducted on mice revealed that fetal exposure to CBD could lead to altered development, affecting thermal pain sensitivity and the ability to solve problems in the offspring. These results, published in Molecular Psychiatryhave implications for pregnant women who use CBD for its anti-nausea properties.

The nausea and vomiting experienced by many pregnant people, commonly known as morning sickness, can be quite debilitating. Some expectant women turn to cannabis for its anti-nausea properties, believing it to be safe. Cannabis contains two main components: cannabidiol (CBD) and tetrahydrocannabinol (THC). While THC is known for its psychoactive effects, CBD is not. Since the legalization of CBD in 2018, it has become widely available not only as part of cannabis, but also as a standalone product.

CBD is known for its anti-nausea properties and is effective in relieving nausea. However, the study aims to understand the potential risks associated with fetal exposure to CBD and its impact on neurodevelopment.

“People take CBD to help with nausea, anxiety, pain and sleep problems, which are common symptoms of pregnancy,” said study author Emily Bates, an associate professor at the University of Colorado Anschutz Medical Campus. “In fact, people recommended taking CBD to help with nausea during my pregnancy. However, there was very little published data on how CBD affects fetal development.”

To explore the effects of fetal exposure to CBD, researchers conducted a comprehensive study with female mice. They administered CBD to one group of pregnant mice and a control substance (sunflower oil) to another group, completing the measured oral consumption of CBD. The dose used was equivalent to what the National Institute on Drug Abuse (NIDA) recommends for intraperitoneal injection in mice.

The study included 27 pregnant mice in each group, and the researchers closely monitored the animals during pregnancy. They tracked weight gain to ensure healthy fetal development, removing any mice that did not gain adequate weight during pregnancy.

Blood samples from the mice were collected at different time points and analyzed to quantify CBD and its metabolites using specialized equipment. This allowed the researchers to confirm the presence of CBD and its degradation products in the plasma of the mice.

The researchers found that male offspring that had been exposed to CBD during fetal development showed increased sensitivity to thermal pain. This means that they reacted more strongly to heat stimuli. This effect has been linked to the TRPV1 receptor, which is activated by CBD and heat. Interestingly, the researchers found that this heightened sensitivity was not observed in the female offspring.

On the other hand, female offspring that had been exposed to CBD during fetal development showed reduced problem-solving abilities. This was assessed using the puzzle box test, which measures the cognitive function associated with the prefrontal cortex. The study also revealed that fetal exposure to CBD decreased the excitability of pyramidal neurons in the female prefrontal cortex. This effect was not observed in male offspring.

“These preclinical studies suggest that CBD consumption during pregnancy is not without risk to the developing baby,” Bates told PsyPost. “People who are pregnant should consult with clinicians about the best alternatives for treating nausea and other pregnancy symptoms.”

Contrary to previous studies, fetal exposure to CBD did not appear to significantly affect anxiety behaviors or compulsivity in the offspring. Multiple behavioral tests were performed, including the open field test, the light-dark box test, and the elevated zero maze test. However, the results did not show any substantial difference between the CBD-exposed group and the control group in these aspects.

“We were surprised that gestational CBD exposure did not impact anxiety behaviors in mice because gestational cannabis exposure is associated with an increased incidence of anxiety in humans and CBD activates a receptor that regulates anxiety,” Bates said. “However, we tested anxiety well and found no differences based on treatment.”

While this study provides valuable insights into the potential consequences of fetal exposure to CBD, there are some important limitations to consider. First, the research was done on mice, and the extent to which these results apply to humans remains uncertain. Second, the study focused on a specific set of behaviors and physiological responses, and the broader impact of CBD exposure on neurodevelopment deserves further investigation. Also, the study used a specific dose of CBD, and different doses could produce different effects.

“Our studies were completed with very high doses of CBD to reveal any subtle effects of CBD on brain development,” explained Bates. “However, we are currently studying how maternal consumption of lower doses of CBD affects the development of the offspring.”

The study, “Fetal cannabidiol (CBD) exposure alters thermal pain sensitivity, problem solving, and prefrontal cortex excitability,” was written by Karli S. Swenson, Luis E. Gomez Wulschner , Victoria M. Hoelscher, Lillian Folts, Kamryn M. Korth, Won Chan Oh, and Emily Anne Bates.