Cannabis use and pregnancy is a tough topic. The unknown effects of cannabis on developing babies are concerning enough to bring pause to the medical community and usually results in a firm recommendation to avoid all cannabis during pregnancy. But rising legalization makes it impossible to ignore the fact that women think cannabis consumption is safe and they are using it during pregnancy. Refusing to approach the conversation does little to further our understanding.
The FDA “strongly advises against” using cannabidiol (CBD) during pregnancy, but admits that there is little to no valid research on the effects of CBD alone on the developing fetus, pregnant mother, or breastfed baby. The regulatory body also stops short of recognizing any wellness benefits of the substance outside of its approved use in prescription medications.
Every pregnant woman makes the choice that she thinks is best for herself and her baby, which can be challenging even for an experienced mother. But what research exists on the effects of CBD during pregnancy, and does it draw any conclusions?
The risks of substances during pregnancy
Pregnancy is a complex and delicate process for both the mother and the fetus, susceptible to a host of internal and external influences. There are any number of factors that could affect the course of a pregnancy, birth, or lactating baby’s growth. Each process has its own variables, and CBD is just one of many substances whose effects scientists and doctors don’t fully understand either. Pregnant women have to navigate a complex and often changing set of guidelines and best practice recommendations based on ever-evolving research.
Not only is the mother’s body changing physically, hormonally, and physiologically, her baby is developing one of the most complex brains on the planet. This development process is incredibly delicate, and every mother wants to give her baby the best chance of success. Some substances are known to increase the risk of abnormal brain development, but much of CBD’s effects are still unknown.
Limited research on CBD and pregnancy
One of the reasons the conversation around CBD and pregnancy is so complex is the lack of research. But this gap in our knowledge isn’t only due to the limits of cannabis research and prohibition, it’s also due to the fact that doing research on and testing the effect of substances on pregnant women or lactating mothers is nearly impossible. No investigation review board in their right minds would ever approve of testing substances on a pregnant mother and fetus, so most of the research we have is limited to preclinical and rodent trials, as well as anecdotal reports or self-reported, retrospective studies.
This lack of understanding and the potential risk to the baby is the reason cannabis in any form is usually discouraged during pregnancy and breastfeeding. But women have used cannabis during pregnancy regardless of the legal status or scientific recommendation, and will continue to do so. Refusing to have a conversation around this topic only continues to fuel the stigma of cannabis use.
There are studies that suggest using THC during pregnancy could be harmful to a baby’s development, though there is no conclusive evidence.
Research has shown that early use of cannabis, specifically THC consumption, can be damaging to a growing brain in children and teenagers. So, it stands to reason that it could also be damaging during pre- and postnatal brain development. 1Most studies have found no conclusive evidence showing that cannabis use increases the risk for birth abnormalities, preterm birth (<37 weeks), or neonatal intensive care admission. 2There is evidence to suggest that mothers consuming marijuana are more likely to give birth to a child with Low Birth Weight (LBW). 3There is conclusive evidence showing that THC crosses into the placenta – meaning it can pass from the mother’s blood and into the fetus’ body and brain. Because human brains contain endocannabinoid receptors as early as 14 weeks into gestation, THC levels may negatively impact fetal brain development through the mother’s repetitive use. 4 5
Research suggests that the endocannabinoid system (ECS) plays an important role in pregnancy, and while external cannabinoids like THC and CBD stimulate this system, exposure to these cannabinoids can alter fetal development. 6
CBD and pregnancy
Why do women turn to cannabis during pregnancy? Are there any products they can use safely?
Morning sickness can be common during pregnancy, but a more extreme form of morning sickness called hyperemesis gravidarum (HG) occurs in 1 – 2% of pregnant women. Symptoms of HG include severe nausea, vomiting (more than four times a day), weight loss, and dehydration. The symptoms are much more intense than your average bellyache; nausea is often resistant to standard nausea medication, and can often require hospitalization to administer IV hydration.
Cannabis use had a “dramatic effect” on these symptoms and the severity of HG, according to a small study published in 2020. CBD has similar antiemetic properties to THC and may be a viable, non-impairing option when prescription antiemetics fail to provide relief to patients dealing with intense HG symptoms. 7 8
Back pain/ muscle stiffness
As the baby grows, the mother’s belly begins to change as well, which often causes weight gain and changes in posture. These changes can cause significant muscle stiffness and strain on the back. CBD has well-documented anti-inflammatory properties which may account for its ability to relieve pain. 9 10
CBD topicals may provide a better option for pregnant and breastfeeding women over Tylenol or other OTC pain medications. Topical products activate the endocannabinoid system receptors in your skin, but generally don’t pass through into the bloodstream. This means that CBD and topical cannabis in general may provide relief for expecting mothers without triggering worries about exposing the baby to cannabis.
Sleep disturbances are incredibly common in pregnant women; in one study 78% of pregnant women reported sleep disturbances. CBD doesn’t impact sleep the same way THC does, and is often thought to be wakeful in small doses and sedating in higher doses (though the data remains unsettled). 11 12
There are an endless number of things to worry about during pregnancy and parenthood that can trigger or worsen existing anxiety. At low doses THC tends to calm anxiety, but higher doses can actually cause it. CBD can help some people with anxiety at low or high doses and higher doses have not been found to cause anxiety. Common prescription medications used to treat anxiety carry definite harmful effects to the fetus, which is why CBD could be a more favorable alternative. 13 14
Although it may not be the first reason that comes to mind – women are often aware of many tips and tricks for increasing or stopping lactation. While substances like alcohol and tobacco can negatively affect milk flow, cannabis’ effect remains largely unknown. There is some anecdotal evidence that cannabis may help increase milk flow, but this is unsubstantiated by current research. In fact, there is reason to believe that THC from cannabis can alter certain hormone levels (like oxytocin and prolactin) and could reduce overall milk production. As for cannabidiol’s effect on breast milk, the jury is still out. 15 16
Studies do show that THC levels can build in breast milk and transfer to the baby in concentrations as much as eight times higher than the mom’s own THC levels. This of course depends upon the amount and frequency that mom is consuming. Science clearly shows that a healthy endocannabinoid system is critical to brain development. There is also an abundance in science suggesting that THC exposure can have an impact on the ECS and therefore on normal neurodevelopment. For this reason, most medical professionals advise against consuming cannabis while breastfeeding.
These concerns are less clearly defined when it comes to cannabidiol. CBD is lipophilic, or fat loving, just like THC – so it can also accumulate in breast milk. This means it can pass through the milk and into the baby’s body and brain. However, the effects of CBD on the health of the infant has not been well studied. 17 18
THC versus CBD in pregnancy
But most studies are done on THC and pregnancy – not CBD. CBD is not intoxicating and has a different mechanism of action in your body, so does that change the safety levels? The short answer is that it’s still too early to say.
A rodent study published in 2021 found that exposure to CBD in the womb had “mixed behavioral outcomes” but “perturbed” the brain epigenome, which is responsible for the way genes express themselves. CBD exposure increases anxiety and improved memory in female mice, without a significant change in male mice. 19
But much of the risk level with using CBD in pregnant humans remains unknown. A known concern is the prevalence of mislabeling within the underregulated hemp space. A 2022 study from Johns Hopkins Medicine found that 11% of CBD products that claimed to be “THC-free” actually contained THC, and only 24% of products were correctly labeled. Product quality issues that permeate the CBD industry in this way can invalidate research and can also raise questions around the safety of products.
Bottom line on CBD use during pregnancy
Is CBD safe to use during pregnancy? Very few substances are considered safe for regular use while you’re pregnant or breastfeeding. There is a risk versus benefit analysis that every expecting mother has to weigh for herself. The existing research heavily suggests that exposure to any phytocannabinoids, including CBD or THC, can negatively impact fetal development, but there is no direct evidence.
The risks carried with CBD consumption are different from the risks of regular alcohol consumption or smoking cigarettes. There is also a difference in consumption that must be considered: applying a topical product to the skin is not the same as exposing the body to systemic cannabis by smoking a joint or taking a tincture.
Ultimately, as a best practice, all medications (including CBD and THC) should be avoided during pregnancy when possible, but that’s a choice every mother has to make for herself and her baby. Using cannabinoids during pregnancy is an evolving conversation that should be guided by scientific research and a mother’s needs.