Trends in Self-reported and Biochemically Tested Marijuana Use Among Pregnant Females in California From 2009-2016

Abstract

Trends in Self-reported and Biochemically Tested Marijuana Use Among Pregnant Females in California From 2009-2016Marijuana is the most commonly used illicit drug during pregnancy, and its use is increasing.From 2002 to 2014, the prevalence of self-reported, past-month marijuana use among US adult pregnant women increased from 2.4% to 3.9%. 1 In aggregated 2002-2012 data, 14.6% of US pregnant adolescents reported past-month use. 2 However, studies are limited to self-reported surveys and likely underestimate use due to social desirability bias and underreporting, leaving the scope of the problem unclear.We investigated trends of prenatal marijuana use from 2009-2016 using data from a large California health care system with universal screening via self-report and urine toxicology.Methods | The Kaiser Permanente Northern California (KPNC) institutional review board approved and waived consent for this study.KPNC is an integrated health care system serving approximately 4 million patients representative of the geographic area.The sample comprised KPNC pregnant females 12 years or older who completed a self-administered questionnaire on marijuana use since pregnancy and a cannabis toxicology test (58% occurred at the same visit as the questionnaire, 87% occurred within 2 weeks of completing the questionnaire) during standard prenatal care (at approximately 8 weeks' gestation) from 2009 through 2016.We estimated the adjusted prevalence of prenatal marijuana use via self-report or toxicology annually using Poisson regression with a log link function, controlling for age, race/ ethnicity, and median neighborhood household income using SAS (SAS Institute), version 9.3.Adjusted prevalence estimates used the average covariate distributions across the study period.We tested for linear trends and differences in trends by age.Two-sided P values less than .05were considered statistically significant.