Cannabis and Pregnancy

Effects of Cannabis During Pregnancy

Cannabis use has been a long debated topic.  With medical marijuana legal support throughout the United States, many people are turning to this herb to help with various medical conditions.  In recent years, the use of cannabis during pregnancy has gained exposure considering it is the most used “illicit” substance during pregnancy.  


Hyperemesis Gravidarum is a severe form of pregnancy-related morning sickness marked by continuous vomiting, rapid weight loss, and malnutrition.  It is the leading cause of hospitalizations during pregnancy.  It most often occurs during early pregnancy but can continue throughout the entire pregnancy in some cases.


It appears that many women are turning to Cannabis as a substitute for prescription meds such as Zofran mainly due to cost.  Unfortunately, there are not many studies on the effects of cannabis use during pregnancy and even less on if cannabis actually reduces the symptoms of Hyperemesis Gravidarum.   


According to a study done in Hawaii, 4,735 women responded to a study survey in regard to their cannabis use by self-administered mailed questionnaires with telephone follow-up call to non-responders.  The survey was completed at the 3 and 8-month postpartum mark.  The survey only represented data that where a live birth occurred.  


According to results of the study, 6% reported using marijuana in the month before their most recent pregnancy.  2.6% reported using marijuana during their most recent pregnancy.  Demographically, the highest estimates of pre-pregnancy use were from women of other or unknown race/ethnicity (12.1%), women below the age of 20 (10.3%), and women with less than a high school education (8.9%). For use during pregnancy, demographically, the highest estimates of use during pregnancy was unknown race/ethnicity (4.6%), women at or below 100% of the Federal Poverty Level (4.1%), and white women at (3.8%) and women with 1-3 years of college education (3.8%).  Bear in mind that other or unknown include African American, American Indian, Puerto Rican, Cuban, Mexican and all others.

Approximately 21.2% of women who had a live birth, reported severe nausea during their most recent pregnancy. Those women were more likely to report marijuana use during pregnancy as well.  Women who reported severe nausea during pregnancy also had a higher rate of marijuana use before pregnancy compared to women who did not report severe nausea during pregnancy.  The study states that the association between pre-pregnancy use and severe nausea during pregnancy was not statistically significant.  


The study states that since medical marijuana has been legal in Hawaii since 2000, that the finding of marijuana use during pregnancy amongst the severe nausea group could indicate that marijuana was used as an antiemetic for those with severe morning sickness.


With this study, the findings were preliminary and admitted that further research needed to be conducted especially on Cannabinoid Hyperemesis Syndrome which is known as a medical condition of nausea and vomiting from a long-term use of marijuana. The question raised is that the possibility of severe nausea in pregnancy could be a result of undiagnosed CHS.


While this study provides a good deal of information on demographics, it lacks the information needed to make any determinations on the safety of marijuana use during pregnancy or even if women were actually using marijuana as an alternative to prescription drugs to treat pregnancy-induced nausea.  The study did not make the survey questions available to determine the exact questions asked of the surveyors.  Also, the groups were not controlled.  It would have been helpful to have a group of women who started marijuana use during pregnancy and used it for the purpose of treating nausea and seeing the health results of their live births including any birth defects. The study did not include women who suffered stillbirths either. The study states that further research needs to be done and that is an agreed upon statement.  While this study provides decent background information, it could not be used to determine if marijuana effectively treats pregnancy-induced nausea or what effects the marijuana had on the infant after birth.  Also, the survey was conducted via mail, so the question of accuracy in answering is a concern.  While medical marijuana use is legal in Hawaii, marijuana use during pregnancy is still taboo and a Child Protective Services concern.  There are studies showing that surveys involving sensitive topics show mis-reportings quite often. Therefore if the study was more controlled, more reliable information would have been provided during the study.


According to a study done by the American Journal of Obstetrics and Gynecology, a study was conducted at seven prenatal clinics in the U.S. from 1984 to 1989.  The study took place through interviews with women who were in 23 to 26 weeks gestation.  The study included 7470 with different ethnicities included.  In this study, the effect of cocaine, marijuana and cigarette smoking was evaluated.  Overall,  11% used marijuana. The findings stated that Marijuana use was not associated with low birth weight, preterm delivery or abruptio placentae. The conclusion of the study was that marijuana use was common during pregnancy yet was not related to adverse pregnancy outcomes.  


While this information was supportive of marijuana use not causing adverse effects, it still did not represent women who strictly used it to reduce symptoms of morning sickness.  Most times women experience nausea during the first trimester.  The women in the study were interviewed at 22 weeks gestation.  The study included a wide range of women and was completed at a university-based clinic.  If a more recent study such as this was conducted, it would be interesting to see the outcomes.  Also, a comparison of the quality of marijuana used would be beneficial as well, as there is currently a concern regarding GMO medicinal marijuana.  


More studies need to be done to determine if Cannabis can help Hyperemesis Gravidarum sufferers without causing birth defects in the child.  While there were tons of reviews and meta-analysis on the subject of marijuana exposure during pregnancy, studies were hard to come by.  Even more scarce is specific studies of women who used cannabis for the specific purpose of treating Hyperemesis Gravidarum.  


Roberson, E. K., Patrick, W. K., & Hurwitz, E. L. (2014). Marijuana Use and Maternal Experiences of Severe Nausea During Pregnancy in Hawai‘i. Hawai’i Journal of Medicine & Public Health, 73(9), 283–287.


Shiono, P. H., Klebanoff, M. A., Nugent, R. P., Cotch, M. F., Wilkins, D. G., Rollins, D. E., … Behrman, R. E. (1995). The impact of cocaine and marijuana use on low birth weight and preterm birth: A multicenter study☆. American Journal of Obstetrics and Gynecology, 172(1), 19–27.