Marijuana and Pregnancy

Why some women use marijuana during pregnancy and what research reveals about it.
Last Updated: February 08, 2019

Throughout Canada, certain states across the U.S., and a variety of places throughout the world, legal medical and recreational marijuana is providing unobstructed access to a growing number of people. This is causing questions to arise about topics such as combining marijuana with other drugs and intoxicants, marijuana and existing health conditions, as well as marijuana and pregnancy.

This last issue is causing increased concern among doctors who are seeing an increasing amount of patients who consume cannabis or its concentrates. This includes many women who are smoking marijuana while pregnant (as well as consuming it via edibles and other methods) in order to control conditions such as morning sickness. While many women insist that marijuana is effective at easing common pregnancy-related ailments, research suggests that expectant mothers should abstain while carrying their babies – and even while breastfeeding after the baby is born.

Marijuana Use During Pregnancy

How many women use marijuana while pregnant? Studies conducted over the years have yielded wildly varying numbers. One study conducted of pregnant women in a Colorado government supplemental food program suggested that nearly 20 percent of women consume marijuana while pregnant. Other estimates range as low as 3 and as high as 30 percent. Statistics published in late 2018 in JAMA Pediatrics estimated that the number of women using marijuana while pregnant over the past 20 years has doubled, with that study placing the current number at around 5 percent. Whatever the actual numbers may be, many experts are certain that any statistics gathered are likely lower than the real numbers, as many pregnant women are hesitant to report their marijuana use, especially in places where cannabis isn’t legal. Behind alcohol and tobacco, marijuana is the substance most likely to be used by pregnant women, which has led to real concern about its effects.

Why Women Consume Marijuana While Pregnant

If it’s true that a large number of women consume marijuana during pregnancy, this raises the question of why. While some recreational users simply fail to abstain even after they’re pregnant, other women turn to cannabis to treat ailments that are common during pregnancy. Some feel that marijuana works better than prescription or over-the-counter drugs suggested by their doctors.

Because women are often hesitant to ask their doctors about the risks versus the benefits of smoking marijuana during pregnancy, they often turn to the internet for information and advice. Marijuana and pregnancy has become a controversial issue, with many people advocating for its safety. An internet search will reveal numerous social media pages and advocacy groups dedicated to women who choose to use marijuana for medical purposes while they’re pregnant. Among those who tout the benefits of smoking marijuana while pregnant, here are some of the conditions they say it helped them with:

Morning Sickness

One of the most common reasons women consume marijuana while pregnant is to deal with morning sickness, general nausea, and low appetite. Apart from simply not feeling well, concern over not getting proper nutrition causes pregnant mothers to seek out relief – especially when prescription anti-nausea medicines have failed.

Although cannabis has been studied as an effective treatment for nausea in patients receiving chemotherapy, it has not been studied an an anti-emetic in pregnant women. Despite this, researchers found that out of a cross-section of 400 cannabis dispensaries in the state of Colorado, 277 of them recommended cannabis as a morning sickness treatment for pregnant women.


Some expectant mothers consume marijuana to help with pain – either pain that they had before they got pregnant or back pain, for example, that has appeared or worsened during their pregnancy. For these women, cannabis offers relief when over-the-counter creams and pain medications have failed. They also feel it provides a better alternative to opioids or other strong prescription painkillers.

Anxiety and Insomnia

Fluctuating hormones and changes in the body can cause anxiety, irritability, and the inability to sleep when a woman is pregnant. This makes marijuana an attractive treatment, as it’s long been studied for its ability to calm anxiety and promote sleep. High-CBD strains are particularly effective at this, and some women who consumed marijuana during their pregnancies say it’s the only treatment that helped them cope during this period of time.

Consumption Methods

For years, it’s been well-established that smoking cigarettes during pregnancy is not only harmful to the mother; it’s also harmful to a developing fetus. Some studies suggest that smoking marijuana carries the same risks in terms of ingesting carcinogens and other toxins, which leads some pregnant women to opt for vaporizing marijuana or consuming edibles or tinctures in order to eliminate the inhalation of smoke.

Vaping, edibles, and tinctures still involve consuming THC, CBD, and other cannabinoids, however. These cannabinoids go into the mother’s bloodstream, through the placenta, and to the fetus. Many experts believe that the ingestion of these compounds – particularly THC – could be dangerous to both mother and baby.

Dangers of Using Marijuana During Pregnancy

Because marijuana has been legalized in numerous places and is often used as an effective medical treatment for a variety of illnesses and ailments, this had led many people to believe that it’s a natural substance that’s safe to use under any circumstances, including pregnancy. However, marijuana is a medication, as well as a recreational substance – and just like any other substance, it can have an impact on both a mother and her baby. What are the effects of smoking marijuana while pregnant? Unfortunately, the evidence shows that using marijuana is far from harmless to pregnant women and developing fetuses. The risks are so concerning that in 2018, the American Academy of Pediatrics issued guidelines warning women not to use marijuana in any form during pregnancy.

Risks to Pregnant Women

While some women use marijuana to treat morning sickness and some of the other conditions that arise during pregnancy, evidence shows that cannabis may create or exacerbate other issues in a way that could create further discomfort or even dangerous health problems.

A 2015 study published by the British Medical Journal found that pregnant women – who are already at a higher risk of anemia – have an increased risk of anemia if they use marijuana before or during pregnancy. The same study found that cannabis use increased the risk of miscarriage.

Another potential problem created by marijuana use during pregnancy is the risk of fainting and dizziness. This can be caused by an increased heart rate and drop in blood pressure – two common side effects of tetrahydrocannabinol (THC). In addition to all of these things, impaired memory and coordination can add to the brain fog that may women experience while pregnant.

Risks to Developing Fetuses

If marijuana can affect a pregnant mother, what about her baby? Does smoking marijuana affect pregnancy? Research shows that marijuana use during pregnancy may reduce the flow of blood and oxygen through the placenta. There are also concerns about the way THC and other cannabinoids may affect the baby itself. After a mother consumes cannabis, it crosses the placenta, causing the baby’s blood THC level to rise to anywhere from one-third to one-tenth of the level of THC in the mother’s blood.

The same British Medical Journal study that looked into anemia, marijuana, and pregnancy also found that babies born to women who used marijuana while pregnant were smaller in size and were likely to require time in neonatal intensive care.

Numerous studies show that marijuana has a negative impact on adolescents’ brains, with some research linking cannabis use in juveniles to a lower IQ. Due to these findings, scientists also believe it’s not healthy for the brains of fetuses.

Studies show that fetal marijuana exposure can have lasting effects after the baby is born. In an article published in Future Neurology, researchers wrote about how prenatal cannabis exposure causes a host of negative effects in infants – from an exaggerated startle response to poor habituation to stimuli. Studies also found that infants whose mothers consumed marijuana during pregnancy suffered from abnormal sleep patterns and increased tremors. As the kids got older, they demonstrated impaired executive function, inattention, and hyperactivity.

Post-Pregnancy: Marijuana Use While Breastfeeding

Even if a woman abstains from marijuana during pregnancy, many believe it’s safe to take up consumption again once the baby is born – even if they’re breastfeeding. Studies on marijuana and breastfeeding have been few, and the ones that have been conducted have yielded highly conflicting results. Two small studies from the 1980s had contradictory outcomes, with one showing no evidence of growth delays and the other showing developmental delays in infants whose mothers had consumed cannabis during the time they were breastfeeding. (One item of note: in the second study, the mothers had also consumed marijuana while they were pregnant.)

One thing is certain: marijuana does pass into breast milk. Because THC binds with fat, breast milk is a particularly good vehicle for it. A 2018 study published in the journal Pediatrics outlined how out of 54 breast milk samples from 50 women who used marijuana, THC was detectable in 34 of the samples. Fecal samples from an infant breastfed by a mother who used marijuana showed an accumulation of THC metabolites.

While the amounts of THC found in breast milk are low, researchers aren’t sure if low means not harmful. “We found that the amount of THC that the infant could potentially ingest from breast milk was relatively low, but we still don’t know enough about the drug to say whether or not there is a concern for the infant at any dose, or if there is a safe dosing level,” Dr. Christina Chambers, the principle investigator of the study, told UC San Diego Health.

Chambers also pointed out that the THC content of today’s marijuana is much higher than it was in the 80s when the original studies took place. Research found that THC levels in the 1990s – a decade after the first breastfeeding studies took place – were at 4 percent on average, while the average THC potency in 2014 was 12 percent.

CBD and Pregnancy

If consuming THC carries specific risks, this leaves many women wondering about cannabidiol (CBD), a non-psychoactive cannabinoid that’s available in many strains of marijuana and abundant in hemp. CBD has been studied for its ability to reduce nausea, quell pain, calm anxiety, and promote restful sleep – many of the issues that plague women during pregnancy.

Unfortunately, scientific studies on CBD oil and pregnancy are too few for doctors to either advise for or against its use. Of the studies that have been conducted, one found that CBD may reduce contractions of the uterus. Although the study was conducted on cells outside the body, it raised questions about whether CBD might lessen contractions while a woman is giving labor. Meanwhile, another study on CBD and pregnancy found that CBD may reduce placental protective functions, meaning that foreign compounds may more easily cross the placental barrier and reach the fetus.

Until more studies on CBD oil and pregnancy take place – and specifically, studies on pregnant humans – many doctors are hesitant to either recommend CBD or tell their patients to avoid it.


Cannabis and pregnancy is a hot button topic, and the internet is awash in information about THC and pregnancy, as well as discussions about CBD oil and pregnancy. Here are some of the questions that are frequently raised when it comes to consuming marijuana during pregnancy.

Is it common for women to smoke marijuana during pregnancy?

Estimates of women who consume marijuana during pregnancy range from as low as 3 to as high as 30 percent. Because marijuana and pregnancy is such a controversial issue, experts believe the actual numbers are greatly underreported, with many women hesitant to talk to their doctors.

What are the benefits of smoking marijuana while pregnant?

Many women say that smoking marijuana while pregnant (or consuming it via vaping or edibles) helped them with ailments such as morning sickness, anxiety, pain, and insomnia. However, studies conducted over the years suggest that the risks outweigh the benefits.

Is smoking marijuana while pregnant bad?

Marijuana use during pregnancy is a personal choice, but studies on cannabis and pregnant reveal potential risks. Among them are the possibility of miscarriage, lower birth weight, infants with an increased startle reflex and abnormal sleep patterns, as well as issues with hyperactivity and impaired executive function in young children.

What about vaping marijuana or consuming CBD during pregnancy?

While smoking marijuana introduces inhaled toxins into the body, vaping or consuming edible marijuana during pregnancy still introduces THC into the bloodstream. As for CBD oil during pregnancy, there are not yet enough studies to prove or disprove its safety.

Marijuana and Pregnancy: A Personal Choice

Even though there are studies that indicate the potential for negative impacts caused by the consumption of marijuana during pregnancy, many women insist that marijuana provided them with a natural alternative to pharmaceutical drugs while they were pregnant. These moms say that having access to marijuana while pregnant helped them maintain their health and sanity during a time when no other treatments worked to quell their nausea, calm their anxiety, or soothe their pain.

While marijuana use during pregnancy is a personal choice, current studies lead most experts and mainstream medical organizations to advise against it. As recreational and medical legalization come to more places, there will likely be more data available to give doctors and expectant mothers a better look at the risks versus the rewards of cannabis during pregnancy.

Dorothy Harris - CNBS Author: Dorothy Harris
Dorothy is far from being a pot-head. Actually, when we first met she wasn’t very familiar with cannabis - but with her excellent research skills and drive for knowledge, it didn’t take her long to master the field. Dorothy comes from a scientific background and is in charge of researching and writing our advanced scientific and medical topics, as their correctness is not something we are willing to compromise on. Dorothy specializes in top notch research, making sure no stone is left unturned.
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