Marijuana During Pregnancy and Breastfeeding

Updated Research Every Family Should Know

Marijuana is often described as natural, plant-based, or safer than other substances. But during pregnancy and breastfeeding, “natural” does not always mean safe. THC, the main psychoactive part of cannabis, can reach the baby during pregnancy and can also pass into breast milk after birth. The CDC says pregnant and breastfeeding parents should avoid cannabis because of possible risks to infant development.

At Birth You Desire, we believe families deserve clear, evidence-based information. Not fear. Not shame. Just honest guidance you can trust.

Updated Research on Marijuana During Pregnancy

A major 2025 systematic review and meta-analysis in JAMA Pediatrics looked at 51 studies and found that prenatal cannabis use was linked with increased odds of preterm birth, small for gestational age babies, low birth weight, and perinatal mortality. The authors said the confidence in these findings is now stronger than in earlier reviews, even after adjusting for tobacco co-use.

That matters because older conversations around marijuana in pregnancy often treated the data as too weak or too mixed to say much. This newer review suggests the evidence is now more solid than it used to be, especially for birth outcomes.

The CDC also states that THC crosses from the pregnant parent to the baby and may affect fetal development. The agency notes possible links to lower birth weight and later problems with attention, memory, problem-solving, and behavior.

What About Brain Development?

Scientists are still studying exactly how much exposure causes harm and whether timing, dose, or product type changes the risk. Medicine cannot confirm a single “safe amount,” because current public-health guidance does not identify one. What current guidance does say is that THC reaches the fetus and may affect the developing brain, which is why major medical groups advise avoiding cannabis in pregnancy.

Marijuana and Breastfeeding: What the Evidence Says

The breastfeeding picture is more complicated than the pregnancy picture.

The CDC says chemicals from marijuana can pass into breast milk, that THC is stored in body fat and released slowly, and that infants may be exposed for an extended period. CDC also advises breastfeeding mothers to avoid marijuana and CBD products because safety has not been established.

LactMed, updated in 2026, says cannabis may affect prolactin, may reduce milk supply or duration of lactation, and that cannabinoids are detectable in milk.

A 2024 human milk study found cannabinoids were measurable in breast milk after cannabis use and stayed elevated with repeated use over the course of a day. That matters because it argues against the idea that timing fully removes exposure.

Another important nuance: newer breastfeeding literature and updated professional guidance do not all frame this the same way. Some newer sources support shared decision-making for parents who continue to use cannabis, rather than treating cannabis use alone as an automatic reason to stop breastfeeding. At the same time, those same sources still encourage stopping or reducing cannabis exposure because safety data are limited and infant risk has not been ruled out.

Preparing for birth and feeling unsure about your options? The Birth You Desire doulas support families in Phoenix, Washington, D.C., and virtually.

What Families Should Take From This

Here is the clearest summary from the current evidence:

During pregnancy, the safest recommendation is to avoid marijuana in all forms, including smoking, vaping, edibles, oils, and concentrates, because newer evidence links prenatal cannabis exposure with worse neonatal outcomes.

During breastfeeding, THC does enter milk, may stay around longer than many people assume, and infant safety is still not well defined. Public-health agencies still advise avoiding cannabis while breastfeeding. Some newer clinical guidance is more nuanced and supports individualized counseling rather than blanket automatic weaning.

Common Myths That Need Updating

Myth: Marijuana is safe because it is legal in many states.
Legal does not mean safe in pregnancy or lactation. The CDC, FDA, AAP, and ACOG all caution against cannabis use in these settings.

Myth: Pumping and dumping solves the problem.
Current evidence does not support that as a reliable fix because THC is fat-soluble, stored in the body, and may persist in milk over time.

Myth: There is a known safe amount.
I cannot confirm any proven safe amount during pregnancy or breastfeeding from the current major medical guidance.

Safer Support Matters

Many parents use marijuana for nausea, stress, sleep, pain, or overwhelm. Those needs are real. You deserve support that takes your symptoms seriously while also protecting your baby as much as possible.

That may include: nausea support, sleep support, mental health care, lactation support, childbirth education, postpartum planning, and hands-on doula care.

At Birth You Desire, we help families understand the evidence, ask better questions, and make informed choices without judgment.

Current Research and Resource Links

CDC, Cannabis and Pregnancy:

CDC, Marijuana and Breastfeeding:

JAMA Pediatrics 2025 systematic review and meta-analysis:

LactMed, Cannabis:

MotherToBaby fact sheet:

2024 Lactation and Cannabis study:

Academy of Breastfeeding Medicine revised guidance:

2025 infant development study in breastfed infants with prenatal cannabis exposure:

Birth You Desire doulas have supported thousands of families through pregnancy, birth, and postpartum.

Have Questions About Your Birth Journey? Talk With A Doula.

The Birth You Desire team supports families in Phoenix, Washington DC, and virtually through pregnancy, birth, and postpartum. During a discovery call, we’ll talk about your goals and answer any questions you may have.