Original Investigation | Substance Use and Addiction

Association of Recreational Cannabis Legalization With Maternal Cannabis Use in the Preconception, Prenatal, and Postpartum Periods

Kara R. Skelton, PhD; Amelie A. Hecht, PhD; Sara E. Benjamin-Neelon, PhD, JD

JAMA Network Open, 2021, 4, (2), 1-12, e210138.

doi : 10.1001/jamanetworkopen.2021.0138

 

Abstract

IMPORTANCE : Recent studies have revealed increases in population-level cannabis use after legalization of recreational cannabis. However, the association of cannabis legalization with maternal cannabis use during important life stages remains unknown.

OBJECTIVE : To investigate the association of legalization of recreational cannabis with maternal
cannabis use during the preconception, prenatal, and postpartum periods.

DESIGN, SETTING, AND PARTICIPANTS : This repeated cross-sectional study used state-level data onwomen who delivered live-born infants in the US from the Pregnancy Risk Assessment Monitoring System from January 2004 to December 2018. Data from 2 states that had legalized recreational cannabis (Alaska and Maine) and 2 states that had not legalized recreational cannabis (New Hampshire and Vermont) were used.Women completed surveys 2 to 6 months after delivery, reporting preconception, prenatal, and postpartum cannabis use.

EXPOSURE : State recreational cannabis legalization.

MAIN OUTCOMES AND MEASURES : The 3 primary outcomes were self-reported cannabis use during the 12 months before pregnancy (preconception), during pregnancy (prenatal), and the 2 to 6 months after pregnancy (postpartum). A difference-in-differences analysis was used to compare changes in the prevalence of maternal cannabis use during each period before and after state legalization of recreational cannabis, controlling for maternal characteristics (age, race/ethnicity, educational level, income, cigarette smoking, and breastfeeding) and state fixed effects. Statespecific survey weights were used.

RESULTS  : The analytic sample included 23 082 women in the preconception period, 23 859 in the prenatal period, and 26 610 in the postpartum period. In each analysis, most women were married (range among all groups, 63.9%-64.8%), aged 25 to 34 years (preconception, 55.4%; prenatal, 55.9%; postpartum, 56.1%), and had an annual household income less than $50 000 (preconception, 55.7%; prenatal, 56.3%; postpartum, 55.5%). In adjusted analyses, preconception and postpartum cannabis use increased significantly in states that had legalized recreational cannabis compared with states that had not legalized it (preconception risk difference, 0.0457 [95% CI, 0.0013-0.0900]; P = .04; postpartum risk difference, 0.0539 [95%CI, 0.0259-0.0818]; P < .001). The risk difference for prenatal cannabis use was not significant (0.0070; 95%CI, −0.0120 to 0.0260; P = .47).

CONCLUSIONS AND RELEVANCE : In this repeated cross-sectional study, recreational cannabis legalization was associated with changes in maternal cannabis use before and after pregnancy. The findings suggest that future studies should undertake an interdisciplinary approach to maximize benefit and application of findings to future public health, health care, and policy sectors.

Key Points

Question : Is there an association between recreational cannabis legalization and prevalence of maternal cannabis use during the preconception, prenatal, and postpartum periods ?

Findings : In this cross-sectional study of 73 551 women, cannabis use increased significantly among women before pregnancy and after pregnancy but not during pregnancy in states that had legalized recreational cannabis compared with states that had not legalized cannabis.

Meaning : These findings suggest the need for interdisciplinary research to better understand how recreational cannabis policies are associated with maternal cannabis use.

 

Introduction

Levels of safe prenatal cannabis use have not been established to date,1 and questions regarding the risk of cannabis use have been the subject of debate.2 However, state-level recreational cannabis legalization in the US, particularly in states with policies that include provisions for cannabis commercialization, make cannabis products more attainable, affordable, and socially acceptable, which may be contributing to increased use.3,4 Cannabis use among women of reproductive age and pregnant women in the US has steadily increased over the past 2 decades.5,6 This increased use may be associated with an array factors at both individual and ecological levels, including decreased risk perceptions associated with cannabis use and increased social acceptance of use.7-9 In addition, recent evidence supports hypotheses that increases in cannabis use may be explained by recreational and not medicinal use.10,11

Under US federal law, cannabis possession and use remain illegal.12 However, the legality of cannabis use is rapidly changing at the state level. As of 2020, 15 states and the District of Columbia had legalized recreational cannabis for adults 21 years and older. Initially, recreational cannabis legalization was a result of voter support, which has doubled since the early 2000s.3 More recently, however, the political climate in the US has led to increased legislative support for expansive cannabis reform and legalization.13,14 This support is evidenced by legalization of recreational cannabis through state legislatures, current pending legislation, and numerous states in which legislative bodies have introduced bills in the past 2 years.13,14 Increases in legislative support, in particular, create an urgent need to examine the public health effects of recreational cannabis legalization, including the association of legalization with maternal and child health.

The extent to which changing recreational cannabis policies are associated with maternal cannabis use during critical maternal and child health periods is unclear. A recent cross-sectional study15 revealed that women residing in states in which recreational cannabis use is legal were significantly more likely to use cannabis during these critical periods compared with women residing in states yet to legalize recreational cannabis. Another recent case study16 in Colorado revealed that prenatal use increased after recreational use of cannabis had been legalized. Most existing evidence is restricted by study design (eg, cross-sectional) or narrow geographic focus (eg, specific state), limiting generalizability of findings.16 In a recent review17 of the prevalence of cannabis use among women during the prenatal period, the investigators found insufficient evidence to assess the association of recreational cannabis legalization with prenatal cannabis use. Cumulatively, prior literature supports the need for more robust evidence examining associations between recreational cannabis legalization and maternal cannabis use during important maternal and child health periods.15-17

To address this gap, we examined whether state recreational cannabis legalization was associated with changes in maternal cannabis use during the preconception, prenatal, and postpartum periods. This natural experiment was possible through geographic and temporal variations in state-level recreational cannabis legalization in the US. On the basis of prior research,15,16 we hypothesized that recreational cannabis legalization would be associated with increases in maternal cannabis use during each period of interest.

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