Vaporized THC During Pregnancy Impaired Attention in Rat Offspring, Especially at Low Doses

Rats exposed to low-dose vaporized THC (10 mg) during pregnancy showed significantly decreased object exploration in both novel object recognition and object-based attention tests, indicating reduced attention. High-dose THC (40 mg) showed some effects on learning patterns but not ultimate performance. Females showed lower attention scores than males in object-based attention.

Pregnant rats were exposed to vaporized THC (10 mg or 40 mg) daily from gestational day 2 until labor. Offspring received standard or high-fat diets and were tested in early and late adolescence using novel object recognition, Morris Water Maze, and object-based attention tests.

This is the first study using vaporized THC for prenatal exposure, which better mimics how humans actually use cannabis. The finding that lower doses produced more pronounced attention deficits is counterintuitive and important for understanding risk at typical use levels.

As vaping becomes the dominant cannabis consumption method, understanding prenatal exposure through this route is critical. The paradoxical dose effect (lower dose worse for attention) may reflect different mechanisms at different exposure levels.

Animal study with vaporized delivery that may not perfectly replicate human vaping. Two dose levels only. Behavioral tests have limited translational validity. Cannot determine if effects persist into adulthood beyond adolescence.