Prenatal cannabis use disorder and gastroschisis in California, 2007-19.

BACKGROUND

Gastroschisis is a congenital anomaly of the abdominal wall with an unknown aetiology. Recent trends in the prevalence of gastroschisis suggest that changing environmental or behavioural factors may contribute. We examined whether prenatal cannabis use disorder was associated with gastroschisis.

METHODS

The Study of Outcomes of Mothers and Infants is a population-based cohort compiled of California birth records that have been linked to Department of Health Care Access and Information hospitalization, emergency department and ambulatory surgery records. We included 2007-19 singleton live births (n = 5 774 656). Cannabis use disorder was measured by diagnosis codes at any visit during pregnancy or at birth. Gastroschisis was measured by diagnosis or surgical repair procedure codes at birth or during the first year of life.

RESULTS

The prevalence of cannabis use disorder was about 1%. The prevalence of gastroschisis was 0.14% and 0.06% among those with and without cannabis use disorder, respectively. There were positive associations between cannabis use disorder and gastroschisis when using a multivariable model [adjusted risk ratio (aRR) = 1.3, 95% confidence interval (CI) 1.0, 1.7) and a matched sample approach (aRR = 1.5, 95% CI 1.1, 2.1). The association varied by maternal age and was largest among people aged >34 years (aRR = 2.5, 95% CI 1.0, 5.8).

CONCLUSIONS

We confirm findings of a positive association between cannabis exposure and gastroschisis and add that it is strongest when maternal age is greater than 34 years. More investigation into whether the association is causal, and why the association varies by maternal age, is encouraged.