Fetal exposure to CBD is associated with altered pain sensitivity and cognitive function

New research sheds light on the potential impact of cannabidiol (CBD) consumption during pregnancy on offspring development. A study in mice found that fetal exposure to CBD can lead to altered development, affecting thermal pain sensitivity and problem-solving ability in the offspring. These findings, published in Molecular Psychiatryhave implications for pregnant women using CBD for its anti-nausea properties.

The nausea and vomiting experienced by many pregnant women, commonly known as morning sickness, can be quite debilitating. Some mothers-to-be are turning 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 stand-alone product.

CBD is known for its anti-nausea properties and is effective in relieving nausea. However, the study aimed to understand the potential risks associated with fetal exposure to CBD and its effects 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 Medical Campus in Anschutz. “In fact, people have recommended that I take CBD to help with nausea during pregnancy. However, there has been very little published data on how CBD affects fetal development.

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

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

Blood samples from the mice were collected at various 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 breakdown products in the plasma of the mice.

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

On the other hand, female offspring exposed to CBD during fetal development showed reduced problem-solving abilities. This was assessed using the puzzle box test, which measures cognitive functions associated with the prefrontal cortex. The study also found that fetal exposure to CBD reduced 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 PsiPost. “People who are pregnant should consult with clinicians about the best alternatives for treating nausea and other pregnancy symptoms.”

Unlike previous studies, fetal exposure to CBD did not appear to significantly affect anxiety-like behavior or compulsivity in the offspring. Multiple behavioral tests were conducted, including the open field test, the light-dark box test, and the zero maze test. However, the results showed no significant differences between the CBD-exposed group and the control group in these aspects.

“We were surprised that gestational exposure to CBD did not affect anxiety-like behavior in mice because cannabis exposure is associated with increased anxiety in humans, and CBD activates a receptor that regulates anxiety,” Bates said. “However, we thoroughly tested anxiety and found no differences based on treatment.”

Although this study provides valuable insight into the potential consequences of fetal CBD exposure, there are some important limitations to consider. First, the research was conducted on mice, and the extent to which these findings apply to humans remains uncertain. Second, the study focused on a specific set of behavioral and physiological responses, and the broader impact of CBD exposure on neurodevelopment warrants further investigation. Additionally, 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 detect the subtle effects of CBD on brain development,” Bates explained. “However, we are currently studying how the consumption of lower doses of CBD in the mother affects the development of the offspring.”

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