The impact of state legalization on rates of marijuana use in pregnancy in a universal drug screening population

Objective: To evaluate the effect of state legalization of rate on marijuana use in pregnancy in a population with universal drug screening. Methods: This is a retrospective cohort study from July 2016 to December 2018 of pregnant women who had universal drug screening of marijuana use before and after legalization of recreational marijuana in California on 1 January 2018. Maternal medical conditions and neonatal outcomes associated with usage were also evaluated. Student's t-test, Wilcoxon rank-sum test, and multiple linear regression were used for statistical analyses. Results: Of 466 women, initial marijuana usage in pregnancy confirmed by urine drug test increased after legalization from 6 to 11% (p = .05). Factors associated with marijuana usage included younger age, white or black race, single marital status, psychiatric disorders, intimate partner violence and concomitant tobacco and alcohol use. 73% of users in this study had cessation of marijuana use with subsequent negative UDT. There was no statistical difference in rates of preterm birth, small for gestational age, NICU admission, or Apgar scores, when adjusted for other risk factors. Conclusion: Rates of marijuana usage in pregnant women who underwent universal drug screening increased after legalization. There were no differences in neonatal outcomes between users and non-users.