Prenatal THC Exposure Reduced Lung Capacity in Infant Monkeys

THC-exposed infant macaques had significantly reduced forced residual capacity, along with decreased total lung capacity, lung diffusion capacity, and lower fetal lung perfusion on prenatal MRI. Molecular analysis revealed altered DNA methylation at genes involved in extracellular matrix organization and lung development.

Female rhesus macaques received daily edible THC (2.5 mg/7 kg/day, equivalent to a heavy medical cannabis dose) or placebo during gestation and postnatally. Serial MRI was performed during pregnancy. At 6 months, infants underwent pulmonary function testing and tissue collection for bulk RNAseq, whole genome bisulfite sequencing, and spatial RNAseq.

Prenatal cannabis use is rising alongside legalization and perceptions of safety, but the respiratory effects on offspring have been largely unknown. This primate model provides more translatable data than rodent studies.

This is one of the first primate studies examining respiratory outcomes of prenatal THC exposure. The epigenetic changes suggest the effects may be programmed early in development, though it remains unclear whether these changes persist into adulthood or cause clinical disease.

Small sample size typical of primate studies. THC was given as a single compound rather than whole-plant cannabis. The dose represents heavy use and may not reflect typical consumption. Follow-up only to 6 months of age. No behavioral or long-term respiratory outcomes.