As cannabis becomes more available for medicinal use across the country, more women wonder if they can continue using their cannabis-derived medicine during pregnancy while others consider using the plant specifically to remedy pregnancy-related symptoms.

The short answer: Due to uncertainties in the research of how cannabis affects pregnancy and fetal development, you should avoid smoking cannabis while pregnant.  However, there’s a lot of interesting research around the topic. 

Can Cannabis Help Pregnant Women Manage Their Symptoms?

The most current comprehensive single piece of literature on the medical efficacy of cannabis is the National Academies of Sciences, Engineering, and Medicine’s 2017 report, “the Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research.”

The report found that there is conclusive evidence supporting cannabis as a treatment for chronic pain in adults, chemo-induced nausea and vomiting, and spasticity symptoms. There is moderate evidence that cannabinoids can improve sleep disturbances, chronic pain, fibromyalgia, and MS. There is also limited evidence that cannabinoids can treat social anxiety disorders and PTSD.

The cannabinoid responsible for much of cannabis’ medical utility is cannabidiol (CBD), a cannabinoid that is non-psychoactive on its own. Additionally, CBD does not cause the kind of adverse reactions that other pharmaceutical drugs might.  Given that pregnant women experience a range of symptoms including nausea and vomiting, pain, and disrupted sleep, CBD’s medical uses are promising.

Cannabis Use Is Rising Amongst Pregnant Women

That may be why the rate of cannabis use among pregnant women in California (one of the few states in the country that does not consider prenatal marijuana use alone evidence of child abuse or neglect) almost doubled from four percent to seven percent between 2009 and 2016.

This trend is also apparent in national data. In 2016, 22 percent of adolescents and 19 percent of young adults had positive cannabis screens during their pregnancies. This 2018 study found that women who had a diagnosis of nausea and vomiting were four times as likely to use cannabis to medicate those symptoms than women who didn’t.

In states where cannabis has been legalized, pregnant women have been targeted by brands claiming that their products reduce morning sickness and other pregnancy-related symptoms. While it's possible these products might work, there simply isn’t enough research to guarantee those claims.

Will Cannabis Use Disrupt Healthy Fetal Development?

We know that cannabinoids cross the placental barrier and can also transfer to a baby through breastmilk. If a pregnant woman consumes THC, her unborn child is also consuming a small percentage of it. If a lactating mother consumes THC, her nursing baby will as well.

What we don’t know is how those cannabinoids affect fetal development. The research on in-utero exposure to cannabis is ambiguous, but it does present some significant warnings. For example, this 2016 study claimed that prenatal marijuana use was associated with an elevated risk of low birthweight and preterm delivery, however, when the data also took into account tobacco use and other factors, the data did not show an increased risk for low birth weight or preterm delivery.

The long-term effects of fetal cannabinoid exposure are unclear as well. A recent study found that: 

"Cannabis use is correlated with psychosis and...endocannabinoids play an important role in neurodevelopment…[this] highlights the importance of evaluating potential long-term consequences of prenatal exposure.”

Some evidence suggests that in-utero cannabis exposure could cause a child to develop hyperactivity and other behavioral abnormalities in childhood. However, the authors also admit that, “genetic, environmental and social factors could also influence the neurobiological effects of early cannabis exposure in humans.” In other words, there may be more involved than just the use of cannabis by the mother while pregnant.

Does consumption type matter?

The way that cannabis is consumed also contributes to its risk profile.  If a pregnant mother smokes her cannabis, she could be exposing the fetus to similar toxins found in tobacco smoke.

Additionally, if the mother continues to smoke postpartum in the vicinity of her newborn, she may be putting her child at risk of inhaling that smoke. Because of the ethical issues involved in studying in-utero cannabis exposure, there are no randomized clinical trials examining the effects of cannabis on fetal development or on nursing infants.

The adverse outcomes reported in the studies that do exist may or may not be attributable to cannabis because it has been difficult for researchers to adjust for confounding factors like tobacco or illicit drug use.

This lack of clarity has led the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists to caution pregnant and lactating women against cannabis use.

An Anecdote Of Cannabis Use While Pregnant

Amy Smith (name changed to protect identity) found herself in the former position when she became pregnant with her first child.

Smith is a US Army veteran living with severe post-traumatic stress disorder. Instead of managing her symptoms with the 20+ pills she was prescribed by her VA doctors, she chose to medicate with marijuana.

Cannabis made it possible for her to resume her daily activities at a functional level. When she got pregnant, she decided to continue treating her illness with cannabis. “When my anxiety showed up when I was pregnant, I knew what I was in for,” Smith told Vox.

“I could pile up the medications [and] eventually end up in the hospital. I chose marijuana instead.” Then there are women like Kristina Hammer. Hammer developed hyperemesis gravidarum, a pregnancy-induced illness that causes severe nausea and vomiting. She maxed out on Zofran and still lost 14 pounds.

Consequently, her baby was not growing at a gestational age-appropriate rate. She turned to cannabis. “Medical marijuana therapy was the only thing standing between me and a long-term stay in the hospital, between life and death for my unborn baby. It was a no-brainer for me, as a mother and long term believer in the greater good of the often misrepresented plant,” she wrote.

Making an educated decision is the safest option

Once she began using pot to treat her hyperemesis gravidarum, Kristina Hammer started gaining weight. Her baby was born at a healthy 6 pounds, 3 ounces and without any complications. Today, her daughter is “a rambunctious, spirited, 4-year-old with a love for life unlike any other.” There are plenty of stories like these that seem to encourage cannabis use during pregnancy.

At the same time, the scientific community remains unsure about the long-term ramifications of in-utero cannabinoid exposure. Until cannabis is more accessible to researchers, pregnant women will have to do what mothers have been doing since life began—trust their instincts and the expertise of doctors to do the best that they can.