Short answer
The CDC, FDA, and ACOG advise against cannabis use during breastfeeding. THC passes into breast milk. No safe amount has been established. No test tells a parent when milk is clear.
What gets into breast milk
THC is fat soluble. It moves from blood into milk fat and stores in body fat. A 2018 study in Pediatrics tested 54 milk samples from 50 women. THC appeared in 63% of samples. Median concentration was 9.47 ng/mL. The highest sample reached 323 ng/mL. THC was detected in milk up to 6 days after the mother's last reported use.
Terminal half-life for THC in plasma runs 25 to 36 hours in occasional users. Chronic users can carry it for days. Newborns clear the compound slower than adults. Their livers have less enzyme activity.
cannabis and breastfeeding effects on baby
Known and unknown risks
Reported infant effects include sedation, lethargy, poor feeding, and slow weight gain. Evidence for long-term effects on brain development is thin. Researchers have not run controlled trials on infants. Most data come from small cohorts and self-reports, which undercount use.
can you smoke cannabis and breastfeed
Smoke adds separate risks. Secondhand smoke links to respiratory infections, ear infections, and higher SIDS risk. Vape aerosol carries the same concern.
CBD products are not safer by default. Regulation is thin. Some contain THC or contaminants.
Supply effects
Cannabis may affect prolactin and milk supply. Study results conflict. Some reports show lower supply with heavy use. Others show no difference.
What providers suggest
- Avoid cannabis during breastfeeding if possible.
- Ask about infant screening: weight checks, feeding logs, alertness.
- Do not smoke or vape near the infant. Residue stays on clothing and surfaces.
- Report use to the pediatrician. Clinical advice depends on dose, route, and infant age.
Pumping and discarding does not clear THC fast. The compound leaves milk at the same rate it leaves blood. Discarding milk delays feeding but does not shorten total exposure.
Unknowns
No threshold dose exists. Frequency, dose, potency, and route all shift exposure. Potency in legal markets has risen. Flower tested near 4% THC in the 1990s. Legal retail flower often tests 20% or higher now.