ACOG's Official Position in 2017: Pregnant Women Should Stop Using Cannabis

The American College of Obstetricians and Gynecologists issued a formal committee opinion stating that pregnant women should discontinue cannabis use, and that doctors should not prescribe or recommend it during pregnancy or lactation. Self-reported cannabis use during pregnancy ranged from 2% to 5% in most studies at the time, and ACOG anticipated that number would rise as more states legalized.

The opinion was based on concerns about impaired fetal neurodevelopment and the added risks of smoking as a delivery method. For women using cannabis medicinally, ACOG recommended switching to alternative treatments with better pregnancy-specific safety data. On breastfeeding, the position was more cautious than definitive: they acknowledged insufficient data to fully evaluate risks but discouraged use given the unknowns.

This wasn't a study finding new data. It was the most influential obstetrics organization in the country drawing a line based on what was known and, more importantly, what wasn't. The 2-5% self-reported use rate was likely an undercount given stigma around disclosure. With legalization expanding, ACOG was positioning ahead of what they expected to become a more common clinical question.

The distinction between "we know this is harmful" and "we don't have enough data to say it's safe" matters here. ACOG's recommendation was largely precautionary — the neurodevelopment concerns were real but not conclusively established in humans at the time.