Maternal Prenatal Cannabis Use and Major Structural Birth Defects.

OBJECTIVE

We evaluated associations between prenatal cannabis use and major structural birth defects of the child.

METHODS

This population-based retrospective cohort study comprised singleton births (January 2011-July 2020) universally screened for substance use at entrance to prenatal care. Prenatal cannabis use was defined as self-reported use or a positive toxicology test during pregnancy. Electronic health record and birth certificate data were used to identify 38 specific major structural birth defects within 8 organ systems (i.e., central nervous, eye, ear, cardiac, orofacial/respiratory, gastrointestinal, genitourinary/renal, and musculoskeletal). Modified Poisson regression models were conducted adjusting for propensity scores.

RESULTS

Of 363,952 infants, 22,494(6.2%) were exposed to maternal prenatal cannabis use, and 6094 infants (2.17%) had a major structural birth defect. Maternal prenatal cannabis use was associated with gastroschisis in the unadjusted (RR = 2.00, 95% CI: 1.25-3.19) and other non-cannabis prenatal substance use (aRR = 1.68; 95% CI: 1.04-2.71) adjusted models, but not in the models adjusted for maternal age or the propensity score. Maternal prenatal cannabis use was associated with omphalocele in the unadjusted model (RR = 3.04; 95% CI: 1.42-6.48), maternal age-adjusted model (aRR = 3.54; 95% CI: 1.68-7.48), other prenatal substance use-adjusted model (aRR = 3.31; 95% CI: 1.50-7.31), and propensity score adjusted model (aRR: 2.92, 95% CI: 1.26-6.77). Cases of gastroschisis and omphalocele were rare: n = 172 (0.05%) and n = 48 (0.01%), respectively. No associations emerged between maternal prenatal cannabis use and any other birth defects. Findings were replicated when cannabis was defined by toxicology testing only.

CONCLUSIONS

Maternal prenatal cannabis use was associated with an increased risk for gastroschisis and omphalocele. Clinicians should provide counseling in a supportive manner to pregnant individuals about the potential harms associated with prenatal cannabis use.