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

New research sheds light on the potential impact of cannabidiol (CBD) use during pregnancy on offspring development. A study in mice found that fetal exposure to CBD can lead to altered development, affecting the offspring’s thermal pain sensitivity and problem-solving abilities. These findings are published Molecular psychiatryimplications 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 expectant mothers turn to cannabis for its anti-nausea properties, believing it to be safe. Hemp 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 alleviating nausea. However, the study aimed to understand the potential risks associated with fetal exposure to CBD and its effects on neurodevelopment.

“People use CBD to help with nausea, anxiety, pain and sleep problems that are common symptoms of pregnancy,” said study author Emily Bates, an associate professor at the University of Colorado Anschutz University of Medicine. “Actually, people recommended that I take CBD to help with my nausea during pregnancy. However, very little data has been published on how CBD affects fetal development.”

To examine 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 the other group, replicating measured oral CBD consumption. The dose used was equivalent to what the National Institute on Drug Abuse (NIDA) recommends for intravenous administration in mice.

The study included 27 pregnant mice in each group, and the researchers closely monitored the animals throughout pregnancy. They monitored weight gain to ensure healthy fetal development by removing any mice that did not gain adequate 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 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 was linked to the TRPV1 receptor, which is activated by CBD and heat. Interestingly, the researchers found that this heightened sensitivity was not seen in the female offspring.

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

“These preclinical studies suggest that CBD use during pregnancy is not safe for the developing baby,” Bates told PsyPost. “People who are pregnant should consult their doctors about the best treatment options for nausea and other pregnancy symptoms.”

Contrary to previous studies, fetal CBD exposure did not appear to significantly affect offspring anxiety-like behavior or compulsions. Multiple behavioral tests were conducted, including the open field test, the light-dark box test, and the elevated zero plus maze test. However, the results did not show any significant differences between the CBD-exposed group and the control group in these respects.

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

Although this study provides valuable insights into the potential effects 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 unclear. Second, the study focused on a specific set of behavioral and physiological responses, and the broader effects of CBD exposure on neurodevelopment warrant further investigation. Also, the study used a specific dose of CBD, and different doses may have different effects.

“Our studies ended up using very high doses of CBD to detect any subtle effects of CBD on brain development,” Bates explained. “However, we are currently investigating how the use of lower doses of CBD by the mother affects the development of the offspring.”

“Effects of cannabidiol (CBD) in the fetus alter thermal pain sensitivity, problem solving, and prefrontal cortex excitability,” authored by Carly S. Swenson, Louis E. Gomez-Wulschner, Victoria M. Helscher, Lillian Foltz, Camryn M. Court, Won Chan Oh, and Emily Ann Bates.