Marijuana and Pregnancy in the Era of COVID-19

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Cannabis (tetrahydrocannabinol, THC) is becoming increasingly legal and available throughout the United States. However, the smoking or ingestion of marijuana is risky during pregnancy. Moreover, in the era of COVID-19, smoking marijuana entails a risk of serious complications for those who do become infected with SARS-CoV2 (the virus that causes COVID-19).

Marijuana cannot be prescribed by a doctor, but patients have access to medical cannabis by way of dispensaries. Additionally, numerous US states have permitted medical use of marijuana by adults. All of this is happening in a culture that is evolving to be increasingly open-minded about pot use. Marijuana has always been available for those who have wanted it but, with legalization, one who may have avoided it before, now can it get it with no fear of arrest, while others who have been using it feel more free to speak their minds about the benefits of cannabis. This is particularly true when it comes to the medicinal properties of cannabis, such as its effects against nausea and pain. In short, the stigma once attached to marijuana use is disappearing and we’re hearing about pot usage by groups of people that a generation ago would have been very silent about. One such group is women who are pregnant or breastfeeding. In the years since marijuana legalization came into effect in Colorado and Washington, it has become clear that about 4 percent of pregnancies occur in women who use marijuana regularly throughout pregnancy. A somewhat higher number of mothers are estimated to use marijuana while breastfeeding, but the numbers are modest compared tobacco, which is smoked by 12-20 percent of pregnant women. On the other hand, the numbers of pregnant pot users, while relatively low, are thought to be up, compared with what they were prior to legalization.

At the same time, there is a great deal of misinformation circulating in connection with THC and its effects during pregnancy. The issue has been covered before on The Pulse, but it’s important enough to warrant a follow up in the era of COVID-19.

Studies have been few, generally involving small numbers of women, and notoriously difficult to control for numerous factors that could confuse the outcome. Women who use THC tend also to be tobacco users, which means we have to take most study results with a big grain of salt. Importantly, early indications from laboratory animals studies do suggest that THC can have a very negative effect on fetal brain development, particularly when it comes to the forebrain –that’s the part of the brain that you use to think. There is also some concern about THC and low birth weight. Unlike fetal alcohol syndrome and many effects of tobacco on the newborn, effects of THC consumed during pregnancy may present in more subtle ways, and later in a child’s life. Expanding on animal studies to test clinically for negative consequences of drug is very difficult. Generally, it requires a large population of women using the drug during pregnancy for a generation or more, as happened with tobacco and alcohol.

As for breastfeeding, studies are ongoing. A study, for instance, is looking at lactating women who are taking specific doses of THC and pumping out their milk, which then gets sent for laboratory analysis, while the children born from the volunteers are nourished safely with infant formula. Meanwhile, however, there have been some initial studies suggesting that TCH not only makes its way into breast milk, but, much like nicotine, is concentrated in the milk.

Relevant to COVID-19, studies have reveled that smokers, and also vapers, of cannabis products (as well as tobacco) have a substantially higher risk of developing severe complications of COVID-19 compared with nonsmokers who match them in terms of age and other risk factors. This includes even occasional marijuana use. One study by researchers in the UK found that smokers are more likely to suffer, not only the types of COVID-19 complications that require admission to an intensive care unit, often with mechanical ventilation, but also gastrointestinal problems and a range of other COVID-19 complications.

Where does all of this mean for you if you are pregnant and considering using marijuana? The safe route would be “don’t do it”. When confronted with an individual who claims to be an authority, and who suggests that marijuana should be safe, since there is not any strong evidence that it does harm, consider whether that same individual would present a similar attitude if asked about a new pharmaceutical. And finally, if after putting off marijuana throughout pregnancy, if you find that you need it after giving birth, do not take on the role of breastfeeding. With all the unknowns floating around, comfort yourself remembering what we know for certain, that infant formula that you buy at the store is guaranteed not to contain THC.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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