Pregnant and breastfeeding individuals should be cautious about using cannabis, as new research suggests potential harm to developing children. A preclinical study conducted on rats highlights the risks associated with using THC (Δ9-tetrahydrocannabinol) or CBD (cannabidiol) during pregnancy.
Researchers from the University of Western Ontario and Queen’s University discovered that rats exposed to THC and CBD in utero exhibited significant developmental changes, even when these substances were administered without additional cannabis compounds. THC, a psychoactive compound, crosses the placenta and enters fetal circulation in concentrations similar to those in maternal blood. Human fetuses have cannabinoid receptors as early as 14 weeks of gestation.
CBD, though often regarded as non-intoxicating, also crosses the placenta and affects fetal development. In the study, rat mothers were given daily doses of THC, CBD, or both throughout pregnancy. Offspring exposed to THC or CBD alone had reduced birth weights compared to control rats, with those exposed to both compounds showing even lower body and brain weights. While some growth rates normalized by adolescence, behavioral changes and disrupted neuronal activity persisted in certain brain regions.
These findings align with human health studies linking cannabis use during pregnancy to low birth weight, cognitive and behavioral changes, and increased risk of neuropsychiatric disorders. David Natale from Queen’s University emphasizes the study’s role in helping clinicians communicate these risks effectively.
In the US, cannabis use has become more common among pregnant individuals, with surveys indicating increased use for managing mood, morning sickness, pain, or sleep issues. The US Surgeon General, the American College of Obstetricians and Gynecologists, and the American Academy of Pediatrics all advise against cannabis use during pregnancy in the absence of further evidence.
Although rat studies cannot definitively prove the dangers of cannabis use during pregnancy, they offer valuable insights into potential risks. The current research found that male rat offspring exposed to THC exhibited impaired cognitive behavior in adolescence, while female offspring showed minimal neurological changes. However, both male and female rats exposed to CBD alone or in combination with THC displayed neuropsychiatric issues, including anxiety-like and impulsivity-like behaviors.
The study underscores the need for more rigorous research on the effects of cannabis use during pregnancy and its potential impact on fetal development.
