Young-Wolff KC, Ray GT, Alexeeff SE, et al. - Findings demonstrate a significant increase in the rates of biochemically verified prenatal cannabis use during the COVID-19 pandemic among pregnant women in Northern California. Prenatal cannabis use leads to health risks such as low infant birth weight and potential effects on offspring neurodevelopment. Therefore, clinicians are advised to educate pregnant women regarding the harms of prenatal cannabis use and support them to quit as well as offer them resources for stress reduction.

• This study included all KPNC (Kaiser Permanente Northern California) pregnant women screened for prenatal cannabis use.

• Total pregnancies were 100,005; of which, 26% were Asian or Pacific Islander; 7%, Black; 28%, Hispanic; 34%, non-Hispanic White; and 5%, other, unknown, or multiracial.

• Prior to the pandemic, the standardized rate of prenatal cannabis use was 6.75% of pregnancies, and rose to 8.14% of pregnancies during the pandemic.

• Interrupted time-series (ITS) analysis revealed that prenatal cannabis use rose by 25% during the pandemic over prenatal cannabis use during the 15 months prior to the pandemic.

• As corroborated by ITS analysis, these rates prior to and during the pandemic were stable, with no statistically significant month-to-month trends.