Breastfeeding,  Health Concerns

Is Smoking Weed While Breastfeeding Safe?

Marijuana legalization in Colorado and other states has restarted the debate on the benefits and ill effects of “weed.” Currently, medical studies show that the cannabis weed–where marijuana is drawn from–can be used as a painkiller, to manage epilepsy, and even to calm PTSD (Post-Traumatic Stress Disorder) patients.

At the same time, it is also known that marijuana is responsible for a “high.” That in itself becomes cautionary. Smoking marijuana increases the heart rate to twice as fast as normal for more than 2 hours. As it is smoking in general, it can lead to lung problems and infections.

Dizziness is normal, as is shallow breathing, a slower reaction time in general, unfocused thinking, and so forth. It is also addictive, without a doubt. 1 in every 10 users become dependent on it. Also, despite causing a fuzzy, relieving high, it can worsen states of depression, anxiety, and psychosis. So, is smoking weed while breastfeeding safe?

Why Is Smoking Weed While Breastfeeding An Issue?

What has been definitely proven is that marijuana taken by the breastfeeding mother, in any form (smoke, brownies, tea), will make it into the baby’s body. Breastfeeding babies whose mothers take marijuana show tetrahydrocannabinol (THC; the chemicals that induce a high) in their urine. There is no other way they could have taken in the chemicals except through breast milk.

THC is a chemical that is “fat-soluble”–in other words, when it enters the bloodstream, it stores itself in the user’s fat. A mother’s breast milk is only 4.2 grams fat in every 100 milliliters, but the calorie content is 70 grams, and it mostly comes from the fat content. When the mother takes in THC, it dissolves wherever it finds fat: including breast milk. Therefore, the baby takes in THC. Smoking weed While breastfeeding definitely has some effect.

Is Smoking Weed While Breastfeeding Safe?

First of all, there is a noted lack of studies in this area. There are so many factors besides THC that could lead to lower motor and speech development, and even apathy, in breastfeeding babies. The problem is that there is almost no study that could isolate the specific effects of marijuana in those babies. However, it is important for mothers and families, new and old, to know the possible dangers that marijuana can pose to a breastfeeding baby. Only then may an informed choice be made.

Science on Smoking Weed While Breastfeeding

In Favor

In a 1990 study by SJ Astley and RE Little published in Neurotoxicol Teratol, they studied 136 babies breastfeeding until 1 year old. Exactly half, or 68 babies, were breastfeeding from mothers who were taking marijuana at the time. The other exact half were breastfeeding from mothers who did not touch marijuana while they were feeding their babies.

They discovered that at 1 year old, the 68 babies taking in marijuana through their mothers’ milk had lower motor development (less maturity in motion) than the 68 who were not. Since the mothers’ marijuana intake was regular, it was suggested constant intake could cause such problems.

Another study by Mohican Ranganathan and 6 other authors was published in Psychopharmacology (Berl) in 2009. It looked at the effect of cannabinoids (the chemicals in marijuana, including THC) on certain hormone levels, especially prolactin (the hormone that signals the mother to produce breastmilk). The study had 36 healthy individuals, and 40 regular users of marijuana.

What the study discovered was that there was a significant effect on prolactin in frequent marijuana users. Prolactin was decreased and suppressed in those marijuana users. For breastfeeding mothers, it means less prolactin in the bloodstream, less signals to a mother’s body to make breast milk, and less breast milk in general. In other words, smoking weed while breastfeeding is not safe.


On the other side of the debate is a study by Katherine Tennes and 6 more authors on the effects of marijuana intake on babies before and after birth, and during breastfeeding. There were 498 non-users of marijuana, and 258 users in the study. Before birth, there was no noticeable effect on the babies’ growth and development.

After birth, there was no difference in baby response and development when comparing non-users to light, medium, and heavy marijuana users. Even in the follow-up study in one year, there was no difference in the motor or intellectual development of the babies who were breastfed by mothers taking marijuana. The weaning age was normal, as was the expected weight of the babies.

A study supporting these findings was more incidental. Ilet, KF and 4 other scientists conducted a study on the effects of buprenorphine and norbuprenorphine on babies who received the chemicals through breast milk. During the study, they discovered that some mothers had been using marijuana while breastfeeding. The study eventually concluded that there was no damage or change in the babies, even those who were drinking from mothers taking marijuana.

Who Can You Consult On Smoking Weed While Breastfeeding?

With these scientific studies seemingly contradicting each other, mothers need to know who they can go to for information and support. At least, before using or deciding not to use marijuana, they will be informed enough to make a clear, personal decision.

Your Obstetrician-Gynecologist

OB/GYNs, as they are often nick-named, are not just doctors who help deliver babies. Their specialization is the health of both baby and mother while the baby is still in the stomach. They carefully study what might damage the babies in the wombs, and what might continue until after they are born. They can be consulted on the possible dangers of taking marijuana while breastfeeding.

Your Lactation Consultant

Lactation consultants are a less-known force in the medical world, but they may be even more helpful than the local pediatric clinic or OB/GYN. Their specialization is nothing less than helping mothers and advising them in a counseling and even medical role on breastfeeding.

Look for an IBCLC (International Board Certified Lactation Consultant) after the name. It means they have completed the many requirements needed to take the board exam, and have passed the exam. They are qualified to instruct you on breastfeeding and any other related questions.

Your Local Mother-to-Mother Support Group

Sometimes, you know the studies and simply need support in your decision. Or, you need to at least have opinions from mothers who have gone through the same decision-making. You can go to your local mother-to-mother support group. La Leche League is one of those, and there are other local and international places you can find to help.

Smoking Weed While Breastfeeding: Err on the Side of Safety

For pregnant and breastfeeding mothers in general, erring on the side of safety is the best decision–you can continue to buy your bong from your online headshop, but maybe switch to tobacco. However, this decision remains fully personal as long as scientific studies do not lean one way or another on this issue. At the end of the day, turn to the right people to consult, and make an informed decision on this issue.