BACKGROUND: Prenatal alcohol exposure can lead to a wide range of neurological and behavioral deficits, including alterations in motor domains. However, much less is known about the effects of prenatal cannabis exposure on motor development, despite cannabis being the most consumed illicit drug among women. Cannabis use among pregnant women has become increasingly popular given the widespread perception that consumption is safe during pregnancy. Moreover, alcohol and cannabis are commonly used together, even among pregnant women. Yet few studies have explored the potential consequences of combined prenatal exposure on behavioral domains.

METHODS: Using our previously established model, during gestational days 5 to 20, four groups of pregnant Sprague-Dawley rats were exposed to vaporized alcohol, delta-9-Tetrahydrocannabinol (THC) via electronic (e-) cigarettes, the combination of alcohol and THC, or a vehicle. Following birth, offspring were tested on early sensorimotor development, adolescent motor coordination, and adolescent activity levels.

RESULTS: Prenatal THC e-cigarette exposure delayed sensorimotor development early in life and impaired motor coordination later in early adolescence; combined prenatal alcohol and THC exposure did not have additive effects on sensorimotor development. However, combined prenatal exposure produced hyperactivity among male offspring.

CONCLUSIONS: Prenatal cannabis exposure may lead to impaired motor skills throughout early development and combined exposure with alcohol during gestation may lead to hyperactivity in early adolescence. These findings have important implications for informing pregnant women of the risks to the fetus associated with prenatal cannabis exposure, with and without alcohol, and could influence public policy.