Effect of In-Utero Cannabinoid Exposure on Foetal Growth and Placental Efficiency

Abstract

Background: Cannabis sativa. L. contains over 550 components, including cannabinoids like tetrahydrocannabinol (THC) and cannabidiol (CBD), which affect the endocannabinoid system and influence human neurodevelopment and physiological functions. Although it has therapeutic potential, cannabis use during pregnancy can disrupt foetal development, especially in the brain and placenta.

Objective: To examine the prenatal exposure to THC and CBD on foetal growth and placental health using a Wistar rat model.

Methods: A total of 24 female rats were divided into four groups; each received orally 150mg/kg/day of THC, CBD, or a combination (CBD and THC) at 150 mg/kg/day. The control received only water and feed. The early-phase administration of cannabinoids occurred from day 6 to 19.

Results: There were substantial reductions in foetal weight. The mean weight was 3.78g in the control group. The THC-exposed group showed a 36% reduction (2.41g), the CBD-exposed group had a 41% reduction (2.22g), and the combined THC/CBD group had a decrease of 3.51g. Significant alterations in placental morphological architecture were observed. The THC and CBD exposure groups exhibited pronounced structural distortions and increased trophoblast degeneration, respectively, whereas the combined exposure showed milder placental changes. The foetal-to-placental weight ratio was significantly reduced in all cannabis-exposed groups.

Conclusion: This study shows prenatal THC and CBD harm foetal growth and placental health. THC caused the most severe effects of reduced foetal weight and placental changes. Therefore, public health initiatives should be intensified to alert pregnant women regarding the risks of using cannabis.