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Emergency Medicine News

The Case for Cannabis

Is There a Future for Cannabis Use in Pregnancy?

Yafai, Sherry MD

Author Information
doi: 10.1097/01.EEM.0000657856.53041.24

    OK, take a deep breath. Put your preconceptions aside, and take a moment just to read.

    There are alarming misconceptions about the health benefits of Cannabis on the internet (also known as the subconscious of the public). It certainly has benefits for some diseases and the potential to help with others, and a natural herbal supplement not made by the pharmaceutical industry appeals to the public. The negative sentiment around pharma coupled with discontent with physicians, bad publicity surrounding hospital births and epidurals, and the movement toward natural home births with doulas have led to more birth plans and a desire for holistic treatment during pregnancy and childbirth.

    Sprinkle in the fact that more midlevels are being given legal independence by vilifying physicians and advertising a more caring, kind, loving practice, and you have the perfect environment for attitudes that make many consider Cannabis in pregnancy. Combine these general attitudes with changes in physician practice that have resulted in shorter visits and a heavier hand prescribing medication, and the results are frustrating for everyone.

    Studies Needed

    Given this environment, a pregnant woman is typically dismissed as a drug addict if she works up the courage to ask her OB/GYN or EP about Cannabis to treat severe vomiting. What do we expect will happen when we treat patients like that? Patients will stop talking to us about what they are using for general wellness and nausea and vomiting in pregnancy. Instead they will seek the advice of the local budtender, a 20-something self-professed Cannabis advisor. Is it any wonder that physicians are not popular with the public and that patients would rather seek advice from a 25-year-old with no medical background?

    But what about the science? Cannabis, specifically THC, smoked daily in large amounts during pregnancy could classify as addiction, especially when this is a time when women tend toward abstinence of all drugs, alcohol, and nicotine. The overwhelming majority of studies on women in pregnancy using Cannabis focus on smoked THC and substances such as nicotine and alcohol, both of which are independently known fetal toxins. Nicotine causes birth defects of the mouth and lips and an increased risk of SIDS; alcohol is linked to miscarriage, stillbirth, and fetal alcohol syndrome, according to the Centers for Disease Control and Prevention.

    Only two studies have separated out daily Cannabis use during pregnancy. The frequently cited 1994 study on women in Jamaica (where people use Cannabis culturally and religiously) showed no differences in the 24 women studied (yes, a very small study). (Pediatrics. 1994;93[2]:254.) A 2016 meta-analysis, which accounted for confounders, nicotine and alcohol, showed low birth weight and an increase in preterm deliveries. (Obstet Gynecol. 2016;128[4]:713.) The National Academies of Sciences, Engineering, and Medicine reviewed more than 10,000 studies in 2017, and found an association between smoked Cannabis (THC) and lower birth weight. It also found limited evidence of a link between maternal Cannabis smoking and NICU admissions and insufficient evidence on an association between Cannabis and chromosomal abnormalities or fetal malformations.

    Side Effects of Zofran

    We need more studies on Cannabis and hemp CBD use in pregnancy that exclude nicotine and alcohol use. This is especially important with increasing recreational usage and recent federal legalization of hemp CBD across the country. One such upcoming study on Cannabis use only during pregnancy with a matched control from Washington State University will be interesting to read! (

    Despite the lack of larger studies, everyone would agree that using any substance daily during pregnancy could constitute a problem and potential negative outcome for the baby and mother. The general recommendation for someone who is using any unprescribed medication daily would be to seek therapy, substance abuse counseling, potentially psychiatric evaluation, and treatment.

    Now we can separate out the daily use and abuse issue from medical indications for THC use, understanding that these are not the same. Current options for hyperemesis gravidarum are vitamins, including B supplements, ginger, and changed and improved diet. Treatment becomes more aggressive with pharmaceutical-based medications, including the popular Zofran. Did you know an estimated 22 percent of pregnant women used Zofran at some point in their pregnancy in 2014? (Harvard Gazette. Dec. 18, 2018; Did you know there is an increased risk of cleft palate deformities with Zofran use in pregnancy? (JAMA. 2018;320[23]:2429; Did you know there is a question of cardiac malformations with Zofran use in pregnancy?

    Perhaps we should put down our pens and have a conversation with our patients. We should discuss the risks and benefits of overprescribing antiemetics, given that the rate of hyperemesis gravidarum is only 0.5 to two percent of pregnancies while we prescribe for closer to 22 percent of pregnancies.

    THC is beneficial for nausea and vomiting in chemotherapy and AIDS-related illnesses; CBD seems to have less benefit in this medical scenario. While THC could be considered in the future for hyperemesis gravidarum, the studies cited have found low birth weight as a negative outcome. Could this be related to a pregnant mom who is vomiting and unable to tolerate PO, the reason she is being treated? There is also a potential increase in preterm birth from six percent (baseline) to 12 percent in daily and chronic users; can this be extrapolated to infrequent use as well? You may note that missing from the list of poor outcomes with THC use are deformities (cardiac, limb, facial, etc.), addiction and dependence at birth, and increased risk of miscarriage and SIDS.

    The question is, given the potential risks of Zofran v. THC for specific cases of hyperemesis gravidarum, which risk would a patient be willing to take, if any?

    Please note that THC use while pregnant may lead to the involvement of child protective services in states where Cannabis is medically and recreationally legal and illegal. I do not recommend that pregnant patients or those thinking about getting pregnant use Cannabis simply because good food, water, and social support are the tenets of a healthy pregnancy. I urge patients to deal with underlying mental health issues and to ask their physicians why they are prescribing any medication and for physicians in states where Cannabis is recreationally legal to talk about it with patients. If you don't, someone else will. Thank you to Genester Wilson-King, MD, an OB-Gyn, for assistance with this article. To talk more about Cannabis in pregnancy, contact her at

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