Is Marijuana Safe While Breastfeeding?

What does the evidence say about marijuana and THC while breastfeeding?

1. THC passes into breast milk and can stay detectable there anywhere from 6 days to 6 weeks, and because THC is stored in fat, a baby can still be exposed even after a parent stops using cannabis. 1
2. A physiologically based model predicted that a breastfed infant receives less than 1% of the mother's weight-adjusted THC dose after smoking, ranging from about 0.34% to 0.88% depending on the infant's age, though researchers note the clinical meaning of that exposure level for a developing infant is still unclear. 2
3. Studies have found that regular marijuana use during breastfeeding may modestly slow an infant's motor development, meaning skills like crawling and walking, without a clear effect on growth or intellectual development in the studies available. 3
4. THC can affect prolactin, the hormone that helps the body make milk, and marijuana use may also change the fat and protein content of breast milk itself, on top of any direct exposure to the baby. 3
5. The American Academy of Pediatrics, the American College of Obstetricians and Gynecologists, and the FDA all recommend that breastfeeding parents avoid marijuana use, a rare point of agreement across major professional and regulatory bodies. 4

How marijuana and THC changes by nursing stage

• Early weeks. In the early weeks of breastfeeding, when your baby is smallest and feeding most often, THC exposure through milk is proportionally highest relative to their size, which is why this is the highest-caution window if you're weighing marijuana use.
• Established nursing. As breastfeeding becomes established, the same avoidance guidance still applies. THC builds up in body fat and is released back into milk over time, so occasional use doesn't clear your system, or your milk, as quickly as many people expect.
• Weaning. Later in breastfeeding or as you're weaning, THC exposure still matters since your baby continues nursing and developing. If you do use marijuana, spacing it as far as possible from feeds, and pumping and discarding milk afterward, can reduce, but does not eliminate, your baby's exposure.