Pregnancy And Breastfeeding – Adverse Effects Of Marijuana

May 8, 2019

For the most part, it’s recommended that women steer clear of drugs during pregnancy. While this rule does apply to marijuana (and literally every other drug), marijuana isn’t as dangerous to fetal health as some other medications.
If the problem is severe enough (such as extreme morning sickness that impacts a pregnancy), marijuana used medically may provide a solution that is a relatively low risk to a developing child.

Marijuana During Pregnancy

Pregnancy and cannabis
While we are not suggesting the use of marijuana by pregnant women, there is currently no research that effectively links marijuana use to any gross birth defects. Claims by anti-pot propagandists have been dismissed by studies that show marijuana has no causal association with fetal alcohol syndrome or other birth defects. There were, however, a couple of studies that indicated that marijuana could result in slightly reduced birth weight—a clear problem for infant health. But, other studies have yet to find anything that suggests adverse effects following that lower birth weight.
To make matters more unclear, another study showed that marijuana use slightly increased birth weight in some instances. Some researchers have noted that chronic maternal cannabis use might hamper later development, but the evidence is again mixed. One study of Jamaican women found improved development scores in children (up to the age of 5) that were born to ganja-smoking mothers.

Prenatal Marijuana Exposure and Child Development

While marijuana use may not impact infants, prenatal use may become a problem in terms of child development. The endocannabinoid system has a significant role in child development, and marijuana directly affects that system. It is, therefore, likely that prenatal marijuana use may impact children later in life, however, researchers are not entirely clear what those impacts may be.

On researcher, Dr. Peter Fried of Carleton University has considered this possibility. He conducted a long-term study on children who had received prenatal exposure to cannabis. The study found that young children were unaffected, but, as adolescents, they performed slightly lower on tests of “executive function,” or the ability to focus and integrate various mental tasks.

The fact that the study failed to find any effects on the children at an early age raises questions about its credibility. It has been suggested that cannabinoids could interfere with how brain cells form new connections, but, if these effects are even real at all, they are very subtle and have yet to be confirmed. Either way, Fried concluded that prenatal drug exposure accounts for only 8% of the variance observed in cognitive tests (this also counts alcohol and tobacco in conjunction with marijuana). Practically all studies agree that alcohol and tobacco have considerably worse prenatal effects than marijuana (Morgan).

Another study looked specifically at THC since it has the ability to change how nerve cells function. They concluded that THC exposure in the womb could make people more likely to develop certain neuropsychiatric illnesses.

Such as:

  • Addictions
  • Eating disorders
  • Mood disorders
  • Sleep disorders
  • Neurotic conditions such as OCD and anxiety

It is also interesting to note that nearly all of these conditions are potentially treatable by marijuana. Again, this study focused on THC and not CBD.

CBD and Pregnancy

A small amount of marijuana to ease the pains and complications of pregnancy is not that unheard of. Many pregnant Western women use it, even if it is illegal, and in places where it is not, more continue to do so. Yet, the idea of using marijuana while pregnant is still highly controversial. Therefore, to avoid unnecessary risk, many people choose nonpsychoactive cannabidiol (CBD) instead. But, is CBD any safer to use during pregnancy?
Unfortunately, there aren’t many studies dedicated to the use of CBD during pregnancy. There are, however, a few pre-clinical studies on cell line and animals – but they are not pregnant humans. There are also studies on synthetic CBD, which is not exactly the same. Therefore, the information these studies provide may or may not be relevant.
Previous studies have identified three key areas of concern:

Early Pregnancy

According to studies done on rodents, CBD may be safer than THC during early pregnancy. Studies show THC may inhibit a women’s ability to get pregnant, while CBD and CBN may not. In the study, THC affected implementation and ovulation (becoming pregnant) as well as embryonic cells (staying pregnant). The rodents that received CBD or CBN developed normal embryos.
If this sounds alarming, we probably should mention that the rats received a higher than average amount of marijuana. When converted to human standards for a slender woman, those mice consumed 306 mg of either THC, CBD, or CBN per day. By today’s medical marijuana standards, that is 3 or 4 pre-rolled joints per day.

Entire Pregnancy

Using CBD during pregnancy may lead to placenta tears. A 2013 study revealed that CBD treatment could cause a more permeable placenta. This is a bad thing because the placenta protects developing humans from substances the mother has consumed. If the mother has been exposed to substances that could harm her child, a damaged placenta is a serious liability.

While this finding should be concerning for pregnant women, it is important to note that many placenta tears are only a problem if the mother has substances in her body that could harm a developing fetus – such as alcohol or nicotine. Hopefully, she has taken other necessary precautions to protect her fetus while pregnant. The placenta can also heal itself, and many tears heal on their own with bed rest. Unfortunately, if they occur in the last trimester and are severe, doctors may perform an emergency C-section.

Late Pregnancy

A 2010 study using synthetic CBD revealed that CBD may reduce labor contractions. They proved this using cells cultured outside of the body. The research was based on earlier studies that showed that a combination of THC and anandamide (a naturally produced endocannabinoid) could do the same thing.

While contractions naturally occur during labor, preterm labor is dangerous because it can lead to premature birth. Therefore, doctors may use pharmaceutical drugs to reduce contractions during preterm labor and frequently prescribe oxytocin antagonists, such as atosiban. Synthetic CBD was comparable to these drugs.

Medical marijuana’s therapeutic benefits need to be weighed against these hypothetical risks. Many women find cannabis useful in alleviating morning sickness. In these cases, treatment of extreme nausea may be more important to fetal health than any negligible risk from prenatal drug exposure. Of course, if the mother has a life-threatening illness like cancer, the risks of fetal exposure are even less crucial.

Breastfeeding and marijuana use

Breastfeeding and cannabis use

The concern around marijuana’s connection to breastfeeding lies in the fact that THC is fat-soluble and a small amount of it gets into the mother’s breast milk. Studies have shown that a fraction of one percent of a mother’s dose of THC might be delivered to the baby (Grotenhermen). One study found absolutely no effect on infant development while another found minor effects that diminished after a month. In any event, the effects appear to be negligible except for heavy, chronic users.

In fact, breastfeeding may be advisable for women who already smoke marijuana, since it helps build an infant’s immune system and protects the baby from the dangers of being exposed to marijuana smoke.

With all of the information that we still do not know about marijuana, it is not clear if it poses any serious risk to pregnant or breastfeeding women. Currently, it is believed to pose less of a risk than most pharmaceutical drugs as well as alcohol and tobacco.

If you are pregnant, breastfeeding, or trying to get pregnant, you should talk to a medical professional about the use of marijuana. 

Thanks for reading. Please leave comments or questions below and don’t forget to download my free grow bible.


The founder of I Love Growing Marijuana, Robert Bergman, is a marijuana growing expert that enjoys sharing his knowledge with the world. He combines years of experience, ranging from small-scale grows to massive operations, with a passion for growing. His articles include tutorials on growing... [read more]


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  1. By Adverse Effects Of Marijuana, Real and Imaginary – ,10 Sep 2015
    […] marijuana’s effects on heartbeat and blood pressure). -Implications for marijuana use during pregnancy and while breastfeeding. -Possible allergic reactions to […]
  2. By Ripp ,16 Apr 2017
    That's real!! "I know a girl" that heavy smoker past 17 years. She.. smoked before, during, after (her pregnancy) and still.. why is the subject so taboo? Hmmm well the boy is amazing and smart and funny... So I just […]Read More

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