Prenatal Alcohol and Cannabinoid Co-Exposure Reduced Fetal Brain Blood Flow More Than Either Drug Alone in Mice

All drug exposures decreased fetal cranial blood flow 24 hours after the final dose. Combined alcohol and cannabinoid co-exposure reduced internal carotid artery blood flow significantly more than either exposure alone. Umbilical artery metrics were unaffected, indicating specific vulnerability of fetal cranial circulation. Post-exposure cerebroplacental ratios predicted perinatal mortality (p = 0.019, AUC 0.772, sensitivity 81%, specificity 85.7%).

Pregnant C57Bl/6J mice assigned to four groups: control, alcohol-exposed, cannabinoid-exposed, or both. Drug exposure daily on gestational days 12-15 (equivalent to late first/early second trimester in humans). High-resolution in vivo ultrasound imaging on three days of pregnancy.

Alcohol and cannabis are frequently co-consumed during pregnancy, but their combined effects on fetal brain development were virtually unknown. This study shows polysubstance exposure confers additional risk beyond either drug alone, specifically targeting fetal brain blood supply.

With rising cannabis potency and availability alongside persistent alcohol use in pregnancy, polysubstance exposure is increasingly relevant. The finding that fetal brain blood vessels are specifically vulnerable, while umbilical circulation is not, suggests a targeted mechanism of developmental harm.

Mouse model using synthetic cannabinoid agonist (CP-55,940), not THC. Intraperitoneal injection plus vapor inhalation does not replicate human consumption patterns. Short exposure window (4 days). Small sample sizes per group.