Earlier this week a new study was published online by Dr. Corsi and colleagues, at the Journal of the American Medical Association. In this retrospective cohort study that included 661, 617 pregnancies and 9,427 reported cannabis users, the rate of preterm birth among reported cannabis users was 12% vs 6% in nonusers, a statistically significant difference. Should we be alarmed?
The truth is that cannabis is here to stay. Legalized, in some form in almost 30 states and counting, the horse is out of the barn. In addition, one of the first and most prominent “legal” uses of medicinal marijuana was for lack of appetite and nausea in cancer and chemotherapy patients. What do women early in their pregnancy also have? Yes, nausea and lack of appetite. Understandably, with the growth of legalization and “holistic medicine”, marijuana use has increased and has become a therapy touted, in some circles, for use in pregnancy. Proponents argue that it is “natural”, “safe” and can help combat the common discomforts in pregnancy. As an Ob/Gyn with a fellowship in Integrative Medicine, I must admit, it is hard to deny these claims. It’s also hard to deny that a few glasses of wine or beer might not provide the same “discomfort” relief….but most women understand it is a bad idea to drink during pregnancy (wine is “natural” too, afterall).
The other unfortunate truth is that we will have a very difficult time ever proving or disproving marijuana’s safety in pregnancy because it is unethical to “experiment” on women and unborn babies. In today’s medico-legal climate, there is no one who would be able to get institutional clearance for a study comparing the outcomes, nor are there many women willing to volunteer for a study where the known possible outcomes of randomization to a study arm could result in malformations, low birthweight, learning disorders, psychosis in the adolescent, or other outcomes not yet associated with marijuana use. At present, there is simply very little information out there on the safety of marijuana use in pregnancy and almost all the information is based on self-reporting of use (a highly inaccurate data collection method). There have only been a handful of papers even looking at the issue and, frankly, they have had conflicting outcomes of clinical significance.
Due to these issues, it is my belief that pregnant women and women who desire to become pregnant abstain from any form of marijuana use, including CBD products (which are not regulated and can contain up to 3% THC in OTC preparations). This is not because I do not believe in the medicinal properties of cannabis, but because as a physician who has spent the better part of her life learning about and caring for women and babies, I can not tell you it is NOT dangerous for you during pregnancy.
As more states legalize marijuana, I suspect the numbers of women who use in pregnancy will increase accordingly and more papers will be written looking at the safety and efficacy profile of cannabis in pregnancy. KM Kuczkowski wrote in 2004, in the Annals of the Academy of Medicine Singapore “Because the pharmacological actions of marijuana are complex and include a unique blend of effects, the clinical picture could be very unpredictable, the diagnosis often difficult, and the management at times controversial.”.
The real question is whether you want to risk your baby to an “unpredictable” outcome?