Association between maternal prenatal cannabis use and missed child preventive care visits in an integrated health care delivery system in Northern California.

The periodicity of well-child visits recommended by the American Academy of Pediatrics emphasizes the importance of continuity of care in health management. Exposure to cannabis in utero has been associated with adverse development, and adherence to well-child visits is critical for earlier detection and intervention. To assess whether maternal prenatal cannabis use was associated with missed well-child visits in the first three years after birth we conducted a longitudinal cohort study in Kaiser Permanente Northern California of pregnant individuals and their children born between January 1, 2011 and December 31, 2018. Maternal prenatal cannabis use was defined as any self-reported cannabis use since becoming pregnant and/or a positive urine toxicology test for cannabis during pregnancy. Well-child visits were defined as an encounter for a well-child visit or physical exam and categorized into seven time periods from birth to 36 months. Modified Poisson regression models were conducted. Of the 168,589 eligible pregnancies, 3.4% screened positive for maternal prenatal cannabis use. Compared to no use, maternal prenatal cannabis use was associated with more missed well-child visits at every time period; (missed 12-month visit: adjusted relative risk (aRR): 1.43, 95%CI: 1.32-1.54; missed 3-year visit: aRR: 1.15, 95%CI: 1.11-1.20). Maternal prenatal cannabis use was also associated with missing two or more well-child visits through 36 months of age (35.8% among cannabis users vs. 23.0% among non-users, Χ2p < .001). Educating pregnant individuals who use cannabis on the importance of well-child visits may benefit children's health and development.