Children of mothers who used cannabis during pregnancy had greater fat mass and adiposity and higher fasting glucose than those not exposed to cannabis, according to study findings.

“We know that cannabis laws are relaxing and there is a misconception that cannabis is ‘safe’ to use in pregnancy,” Brianna F. Moore, PhD, assistant professor in the department of epidemiology and in the Lifecourse Epidemiology of Adiposity & Diabetes Center at the University of Colorado School of Public Health, told Healio. “However, cannabis use in pregnancy has been linked to lower birth weight and adverse neurocognitive effects in the offspring. Our study builds on these previous studies by providing novel evidence that fetal exposure to cannabis is associated with higher glucose and adiposity in 5-year-old children.”

Researchers analyzed data from 103 pregnant women who attended outpatient obstetrics clinics at the University of Colorado Hospital between 2010 and 2014. Mothers who had urine samples collected to measure cannabinoids and metabolites at 27 weeks of gestation were included in the analysis. A follow-up visit was conducted with each participant’s child at a mean age of 4.7 years. Children’s fat mass, fat-free mass, childhood adiposity, fasting glucose and insulin concentrations were measured at follow-up.

The findings were published in The Journal of Clinical Endocrinology & Metabolism.

Among the mothers, about 15% had a detectable level of cannabis at 27 weeks of pregnancy. THC and its metabolites were detected more than other cannabinoids, and the most commonly detected cannabinoid was THC-9-carboxylic acid glucuronide.

Children with fetal exposure to cannabis had 0.7 kg more fat mass at follow-up compared with nonexposed children (95% CI, 0.2-1.2; P = .01). The finding remained significant after adjusting for the duration of breastfeeding and exposure to tobacco. Children with fetal exposure to cannabis had a 2.6% higher fat mass percentage at follow-up than unexposed children (95% CI, 0.1-5.2; P = .04). No significant differences were found with childhood BMI or BMI z score.

Children exposed to cannabis in utero had a fasting glucose level 8 mg/dL higher than those not exposed (95% CI, 0.1-15.8; P = .04). The mean difference was lower after adjusting for breastfeeding and childhood exposure to tobacco but remained significant.

“We were surprised at how strongly fetal exposure to cannabis was associated with childhood adiposity and glucose levels,” Moore said. “This was robust even after controlling for many important confounders, including tobacco use in pregnancy.”

Fetal exposure to cannabis was also associated with 4 uU/mL higher fasting insulin compared with unexposed offspring (95% CI, 0.7-7.3; P = .02), but the difference was nonsignificant after adjusting for postnatal factors.

Moore said pregnant people should follow American College of Obstetricians and Gynecologists recommendations and avoid using cannabis to limit risks to children. With more states in the U.S. now legalizing cannabis, Moore added, more research needs to be conducted on the fetal effects of cannabis use.

“We need to understand how higher doses may impact the offspring and whether CBD, in the absence of THC, is associated with adverse health effects in the offspring,” Moore said.

For more information:

Brianna F. Moore, PhD, can be reached at brianna.f.moore@cuanschutz.edu.