Study: Some women perceive cannabis use during pregnancy as relatively low risk

While it is widely known that the use of alcohol and tobacco are detrimental to a baby’s development, a new literature review conducted by researchers at UBC discovered that people are far less likely to perceive cannabis use to be harmful.

The review analyzes data from six different studies, looking at women’s perspectives on the potential harms of cannabis use and the motivations behind continued use of cannabis during pregnancy. Emerging evidence has linked perinatal cannabis use to low birth weights and increased neonatal intensive care unit admission.

Cannabis use among pregnant populations was found to be highest in the first trimester. The review found that a number of factors — such as the use of cannabis to treat morning sickness, the less expensive cost of cannabis compared to cigarettes and inadequate discussion with healthcare providers on perinatal cannabis use — influenced women’s continued cannabis use.

One study anonymously surveyed women in a prenatal clinic, asking “Do you believe marijuana is harmful to a baby during pregnancy?” In this particular survey, 30 per cent of women responded “no.” In both general and pregnant populations, perception of harm is a strong determinant of cannabis use, as users are far more likely to view cannabis as a low- or no-risk substance.

The study also found that women who used cannabis during their pregnancy perceived a lack of communication of prenatal health risks as an indication that cannabis use did not pose risks to their pregnancy. Although professional maternal health organizations, such as Society of Obstetricians and Gynecologists in Canada and the Canadian Association of Midwives, recommend abstaining from marijuana during the perinatal period, data surrounding prenatal cannabis exposure is still a new area of interest among researchers.

“Sometimes healthcare providers don’t communicate [the risks of prenatal cannabis exposure], just because of the uncertainty,” said Dr. Hamideh Bayrampour, assistant professor in the department of family medicine, midwifery program at UBC.

“But we need to have those conversations … in a very transparent way.”

When discussions were had about cannabis use, they often focused on legal consequences as opposed to health impacts.

Due to the limited research available, data analyzed in this review came from the United States, where the legal status of cannabis varies by state. New data found higher levels of THC in babies’ stool samples post-legalization in states where cannabis was recently legalized. This is consistent with research showing increased use of cannabis in states where cannabis is legal and intentions to increase use upon legalization in prohibition states.

While perinatal use of alcohol has decreased over the last decade, perinatal use of marijuana has increased, from 2.37 per cent in 2002 to 3.85 per cent in 2014. As legal barriers to access are being removed, the weight of legal consequences as a deterrent for perinatal cannabis use weakens. This makes it imperative that healthcare providers and patients discuss the potential risks of cannabis use on their pregnancies and navigate the emerging research together.

“Many of the [prospective mothers] using this substance … [are] already motivated to quit or cut back. So having those conversations in a non-judgemental way, in a safe environment, can help them to start seeking the support that they want,” Bayrampour said.