Management of cannabis use during pregnancy

In most developed countries, approximately 10% of pregnant people smoke cannabis, most often in conjunction with tobacco. Animal and human research suggests that permanent neurobehavioural effects can result from cannabis exposure in utero, and the nature of these depends on the gestation at exposure. Cannabis use in pregnancy is associated with low birth weight and infants being small for gestational age. This may reflect the high prevalence of tobacco use in people who use cannabis. However, the association with low birth weight and small-for-gestational-age infants may be independent of concurrent tobacco useGrzeskowiak, 2020. Children of people who used cannabis while pregnant may have cognitive (especially visuospatial) deficits, greater impulsivity and hyperactivity and higher rates of depression than people without prenatal cannabis exposureWu, 2011. Interpretation of data on harms from cannabis exposure in utero requires caution owing to possible confounding factors.

Explore with pregnant patients their understanding of the risks that cannabis may pose to the fetus, and use motivational interviewing approaches and psychological interventions to support positive change. If they smoke tobacco as well as cannabis, intervention should focus on supporting the person to stop the tobacco use because this has the clearest evidence of causing fetal harm.

Medications to manage cannabis withdrawal symptoms should only be considered after specialist consultation.

With the growing use of medicinal cannabinoids and decriminalisation of cannabis in many countries, there has been an incorrect perception in the general population that cannabis may be appropriate for the treatment of morning sickness. Cannabis and medicinal cannabinoids are not recommended to treat nausea and vomiting during pregnancyBadowski, 2020.