Only two studies examine cannabis use during breastfeeding, with conflicting results | Research

The takeaway

A systematic review found only two studies meeting criteria for cannabis exposure during breastfeeding, with conflicting results on infant developmental outcomes, highlighting a major evidence gap.

Obstetricians, pediatricians, lactation consultants, and breastfeeding mothers who use cannabis.

Only 2 studies exist on cannabis during breastfeeding and infant outcomes

What the researchers found

Despite cannabis being the most commonly used psychoactive substance by 5% of Canadian postpartum women, only two studies met inclusion criteria for developmental outcomes in breastfed infants exposed to cannabis. Results were conflicting, with one showing motor development effects and the other finding no significant impact.

Why it matters

Millions of breastfeeding women worldwide face decisions about cannabis use with almost no evidence to guide them. This review exposes just how little we actually know.

The numbers in context

~5% of Canadian women use cannabis during pregnancy/postpartum; only 2 studies met inclusion criteria; results were conflicting.

How the study worked

Systematic review searching Medline, Embase, and PsychInfo for studies on infant outcomes from cannabis exposure during lactation, with developmental outcomes as inclusion criteria.

What this study cannot tell us

Only 2 eligible studies found; both were older and limited by methodology; cannot account for other substance co-exposures; no data on neurodevelopment beyond first year in included studies.

How to read the evidence

Preliminary: systematic methodology but only 2 eligible studies with conflicting results.

When this study was published

Published 2020.

The bigger picture

THC is known to transfer into breast milk, but the evidence on what this means for infant development is essentially nonexistent. Clinical recommendations are being made on the basis of precaution rather than data.

Questions still open

Should cannabis-using mothers avoid breastfeeding entirely? How long after cannabis use is breast milk safest for infants?

Common questions

Is it safe to use cannabis while breastfeeding?

The evidence is insufficient to answer definitively. Only two studies exist on infant outcomes, with conflicting results. THC does transfer into breast milk, so precautionary advice is to abstain or minimize use.

How long should you wait to breastfeed after using cannabis?

The authors recommend avoiding breastfeeding within 1 hour of inhaled cannabis use to reduce exposure during peak concentration. However, THC can persist in breast milk longer due to its fat solubility.

Read the original research

Cannabis Use During Lactation: Literature Review and Clinical Recommendations.

Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstetrique et gynecologie du Canada : JOGC, 42(10), 1248-1253

View on PubMed ↗Publisher’s paper ↗

Citation

Ordean, Alice; Kim, Gloria. (2020). Cannabis Use During Lactation: Literature Review and Clinical Recommendations.. Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstetrique et gynecologie du Canada : JOGC, 42(10), 1248-1253. https://doi.org/10.1016/j.jogc.2019.11.003