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. 2020 Jan;37(1):59-65.
doi: 10.1055/s-0039-1696719. Epub 2019 Sep 6.

Impact of Marijuana Legalization on Prevalence of Maternal Marijuana Use and Perinatal Outcomes

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Impact of Marijuana Legalization on Prevalence of Maternal Marijuana Use and Perinatal Outcomes

Mayi Gnofam et al. Am J Perinatol. 2020 Jan.

Abstract

Objective: We aimed to assess whether marijuana legalization was associated with a difference in prevalence of prenatal use or an increase in incidence of adverse perinatal outcomes.

Study design: The present study is a retrospective cohort of September and October deliveries in the years 2012 through 2015 at a tertiary center in Colorado. Primary outcome of the study was use of marijuana, defined by self-report or biodetection. Secondary outcomes of the study included growth restriction, spontaneous preterm birth, stillbirth, preeclampsia, and neonatal or maternal death. Marijuana use prevalence was compared by year, and secondary outcomes between two periods, before and after the opening of the first recreational dispensary.

Results: A total of 2,392 pregnant women were included (1,165 before legalization and 1,227 after). More women used marijuana over the period of legalization (trend p = 0.01). Odds of marijuana use were higher after legalization versus before (adjusted odds ratio [aOR] = 1.8, 95% confidence interval [CI]: 1.2-2.6). Incidence of growth restriction was higher after legalization (2.9 vs. 5.1%, p = 0.0084). This difference persisted after adjustment for ethnicity and other drugs in multivariable modeling (aOR = 1.9, 95%CI: 1.2-3.0).

Conclusion: The prevalence of prenatal marijuana use increased over the time of legalization. Further investigation into the population impact of legalization on obstetrical outcomes is warranted given the observed increase in growth restriction.

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Conflict of interest statement

None declared.

Figures

Figure 1.
Figure 1.. Marijuana and other substance use over time, 2012–15
Substance use by year across marijuana legalization for recreational use in Colorado. Use as measured by self-report or as detected by biological sampling. The arrow indicates the opening of recreational marijuana dispensaries in Colorado on January 1, 2014.

References

    1. Metz TD, Borgelt LM. Marijuana Use in Pregnancy and While Breastfeeding. Obstet Gynecol. 2018. November;132(5):1198–210. - PMC - PubMed
    1. Metz TD. What Is New in Cannabis Use in Pregnancy?: Best Articles From the Past Year. Obstet Gynecol. 2018. March;131(3):594–5. - PubMed
    1. Metz TD, Allshouse AA, Hogue CJ, Goldenberg RL, Dudley DJ, Varner MW, et al. Maternal marijuana use, adverse pregnancy outcomes, and neonatal morbidity. Am J Obstet Gynecol. 2017;217(4):478.e1–478.e8. - PMC - PubMed
    1. Ko JY, Farr SL, Tong VT, Creanga AA, Callaghan WM. Prevalence and patterns of marijuana use among pregnant and nonpregnant women of reproductive age. Am J Obstet Gynecol. 2015. August;213(2):201.e1–201.e10. - PMC - PubMed
    1. Metz TD, Stickrath EH. Marijuana use in pregnancy and lactation: a review of the evidence. Am J Obstet Gynecol. 2015. December;213(6):761–78. - PubMed

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