Overview

• Researchers analyzed more than 1,000 follicular fluid samples from IVF patients and identified 62 with detectable THC, comparing their oocytes to matched controls with no detectable cannabis use.
• Higher THC levels were associated with an increased oocyte maturation rate and a lower proportion of embryos with the correct number of chromosomes.
• Immature human oocytes exposed to THC for 24 hours in the lab showed more spindle abnormalities, a mechanism that can disrupt chromosome segregation and impair embryo development.
• The authors stress the results show association rather than causation and note the THC‑positive subgroup was small, underscoring the need for larger studies to assess impacts on fertility and pregnancy outcomes.
• Outside experts, including obstetrician Jamie Lo, advise people planning to conceive to avoid or reduce cannabis use, citing rising prenatal use and increasing THC potency.