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Study breakdown

No known safe level of cannabis use during pregnancy or breastfeeding

ReviewModerate evidence
The takeaway

A review for obstetric providers concluded that in utero cannabis exposure is associated with long-term neurodevelopmental outcomes persisting into young adulthood, and cannabis should not be used to treat pregnancy nausea.

Pregnant women, obstetricians, midwives, and family physicians.

Neurodevelopmental effects persist into young adulthood

What the researchers found

In utero cannabis exposure has been associated with long-term neurodevelopmental outcomes that persist into young adulthood. Cannabis should not be used to treat nausea and vomiting in pregnancy. Chronic cannabis use might lead to cannabinoid hyperemesis syndrome. There is no known safe level of cannabis use during pregnancy or lactation.

Why it matters

Cannabis is the most commonly used illicit substance in pregnancy, and some women use it specifically for morning sickness, making clear clinical guidance essential.

The numbers in context

No specific incidence or outcome data pooled.

How the study worked

Literature review using Ovid MEDLINE searching pregnancy, cannabis, lactation, and cannabinoid hyperemesis terms.

What this study cannot tell us

Narrative review. Underlying studies are mostly observational with confounders. No randomized data on pregnancy outcomes.

How to read the evidence

Clinical guidance review synthesizing available observational evidence.

When this study was published

2020 review.

The bigger picture

The association of cannabis with neurodevelopmental effects into young adulthood suggests effects may not be apparent in the newborn period but emerge over years of development.

Questions still open

  • What are the specific neurodevelopmental outcomes associated with prenatal exposure? Are there dose thresholds below which effects are not detected?

Common questions

Can you use cannabis for morning sickness?
This review concluded cannabis should not be used for nausea and vomiting in pregnancy, citing associations with neurodevelopmental effects and no known safe level of use.
Does cannabis pass to the baby during breastfeeding?
Yes, cannabis compounds can be transmitted through breast milk. The review advises abstaining from cannabis while breastfeeding.

Read the original research

Cannabis use during pregnancy and postpartum.

Canadian family physician Medecin de famille canadien, 66(2), 98-103

Citation

Badowski, Sophia; Smith, Graeme. (2020). Cannabis use during pregnancy and postpartum.. Canadian family physician Medecin de famille canadien, 66(2), 98-103.

Explore the wider topic