Daddy-to-be smokes pot — Will it show up in baby-to-be?

Dear Alice,

My question is regarding marijuana and childbirth. My wife is due in March and I have heard from a friend that the last month of her pregnancy I will have to stop smoking because the newborn will test positive for marijuana. I have searched far and wide the past few weeks with no solid evidence or even articles of discussion regarding this topic. Is it possible to continue enjoying my patience enhancement drug (marijuana) through the end of the pregnancy or will I have to resort to drinking heavily to deal with the mood swings until after the child is born.


You friendly local neighborhood pothead,

Smokey Joe

Dear Smokey Joe, 

As a Papa-to-be, it's great you’re considering the effects of secondhand marijuana smoke on your family. Your concern is warranted — the secondhand smoke could be harmful to both baby and mother. The chemicals from marijuana, specifically tetrahydrocannabinol (THC), may pass through a pregnant person’s system to the developing fetus, which may lead to developmental problems. You mention that it’s difficult to find research on the subject, and that’s true — due to marijuana being illegal in many states and federally, it’s difficult to conduct research on the long-term effects of secondhand smoke from marijuana. From research done on the effects of secondhand tobacco smoke, as well as similarities in the makeup of tobacco smoke and marijuana smoke, it’s generally recommended that you avoid smoking around a pregnant person to reduce the risk of impeding the child’s development. It might be worth looking into smoke-free alternatives, such as edibles, if quitting smoking marijuana is a challenge. It may be helpful to speak to a health care provider or mental health professional about these smoke-free alternatives. 

So what does the research indicate when it comes to marijuana and secondhand smoke? Some studies have examined the effects that secondhand marijuana smoke may have on others. In a well-ventilated space, people in a room with others who are smoking marijuana may exhibit some levels of THC in their blood, despite not having smoked. In an unventilated space, those who inhale secondhand smoke have higher levels of THC in their blood, as well as mild cognitive impairments as if they had smoked. If you do decide to keep smoking marijuana during your wife’s pregnancy, it may be wise to smoke near an open window or outside if it’s legal to increase the ventilation and reduce the risk of ingesting secondhand smoke. 

Direct harm won't necessarily come to a developing fetus' airways (as they will to a baby's), but the brain can be affected as well as the overall development of the newborn. One study found that smoking marijuana while pregnant during the third trimester negatively impacted infant mental and motor development. The New England Journal of Medicine has published numerous studies linking marijuana use during pregnancy to decreases in birth weight and size. In addition, the American Academy of Pediatrics has published studies that found maternal marijuana use was associated with features like fetal alcohol syndrome. Although your wife isn't smoking directly, if she’s inhaling your secondhand smoke, there’s certainly a possibility of consequences for the infant after birth. Some studies have examined the effects of secondhand tobacco smoke on pregnant people and found that exposure to secondhand smoke is associated with delayed mental development in children as late as two years after birth. Due to similar chemical makeups in marijuana and tobacco smoke, some researchers believe that secondhand marijuana smoke may have similar health outcomes. Additionally, because marijuana isn’t regulated in some states, additional chemicals may be added that decrease odor, increase weight, increase potency, etc. These chemicals can increase toxicity beyond that of marijuana with no additional chemicals. No current studies have examined the direct impact of secondhand marijuana smoke on pregnancy — however, some researchers feel that the effects of tobacco smoke may be an indication of what to expect. 

If you’re worried about the potential effects that your smoking may have on your wife and child but aren’t ready to give up your “patience enhancement drug,” you may want to consider smoke-free alternatives. One option is edibles, or foods that contain traces of THC that can be eaten. The latency, or effects, of THC may last longer with edibles than inhalation, and they may also reduce the risk of respiratory and other pulmonary diseases associated with smoking. However, this method of ingestion isn’t without risk. It’s easier to take high doses of marijuana and experience more intense cognitive impairments, as well as increase the risk of overdose. Additionally, if you make a more permanent switch from smoking to edibles, it’s possible that your future child may confuse your edibles for candy or other snacks which could lead to long-term mental health problems. For more information, check out the Go Ask Alice! question Eating marijuana

You mention that your other option for dealing with mood swings is drinking heavily. Is handling mood swings the main reason for using marijuana? Do you believe that these substances are the only way to manage these feelings? Although some people may use marijuana to help with anxiety or mood disorders, there are risks associated with using substances to cope. Parenthood may come with a new set of stressors, and it may be beneficial to think of other coping mechanisms that are associated with fewer risks. Have you spoken with a mental health professional or health care provider about your mood swings? They might be able to offer more coping strategies beyond using marijuana or drinking alcohol to deal with mood swings. It may even be helpful to search for support groups for soon-to-be parents who use marijuana to learn best practices. You’re not alone in your search for answers! 

Congratulations on entering the realm of parenthood and kudos to you for looking after the health of the newest addition to your family. 

Take care, 

Last updated Jun 04, 2021
Originally published Dec 22, 2011

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