Born This Way

With cannabis legal in an ever-increasing number of countries and generally becoming more widely accepted, cannabis use in pregnant women is on the rise (1). Could this be impacting babies’ metabolism? 

A group of US researchers assessed the impact of fetal exposure to cannabis on adiposity and glucose-insulin traits in early life. Using a subsample of 103 mother–child pairs from Healthy Start, an ethnically diverse pre-birth cohort based in Colorado, fetal exposure to cannabis was determined by the detection of 12 cannabinoids and cannabinoid metabolites in maternal urine samples. Fifteen percent of the mothers tested positive at about 27 weeks, with detectable levels of cannabinoids, including CBD and THC, suggesting their fetuses had been exposed to cannabinoids.

In a follow-up visit at age five, the children’s fat mass and glucose and insulin levels were measured after an overnight fast. Results showed that exposed children showed higher fat mass, fat-free mass, adiposity, and fasting glucose compared with non-exposed children – but no differences in insulin levels. The authors suggested this might increase their risk of obesity and high blood sugar later in life.

Although the study controlled for many covariates – including fetal and childhood exposure to tobacco, socioeconomic factors, and BMI z-scores – crucially, the researchers were unable to adjust for some important confounders, such as duration of exclusive breastfeeding, childhood diet, and physical activity.

Nevertheless, the authors believe their study adds to the growing evidence that cannabis use during pregnancy has adverse health effects on children. Though highlighting that their results need to be validated in other cohorts, the researchers strongly discouraged pregnant and breastfeeding women from cannabis use. They also called for the potential risks associated with cannabis use during pregnancy to be more widely communicated to ensure more women are able to make a  more informed decision about cannabis use in pregnancy.