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New study finds recreational marijuana liberalization policies increase maternal hospitalizations involving marijuana but have limited impact on newborn health

BLOOMINGTON, Ind. – A new study on state recreational marijuana liberalization found increases in maternal hospitalizations involving marijuana but limited impact on newborn health.

Angelica Meinhofer

Angelica Meinhofer, PhD

The study is led by Angelica Meinhofer, Assistant Professor at Weill Cornell Medicine, with coauthors from University of North Carolina Wilmington, RTI International, and from Indiana University O’Neill School of Public and Environmental Affairs (Professor Kosali Simon, a Herman B Wells Endowed Professor and the campus’s associate vice provost for health sciences). The team found that the proportion of maternal hospitalizations with marijuana use disorder increased by 23 percent (0.3 percentage points) in the first three years after recreational marijuana laws were implemented. The increases were larger in states with legalized commercial sales of marijuana.

The study (forthcoming in the Journal of Health Economics) was released today as a working paper by the National Bureau of Economic Research.

Researchers studied the effects of both medical marijuana laws (MML) and recreational marijuana laws (RML) on perinatal health (issues affecting women from three months before childbirth up to one year after childbirth), an important question for policy makers as marijuana use among pregnant women increased 103% between 2003 and 2017. As of today, 17 states have implemented recreational marijuana laws and 36 states and DC implemented medical marijuana laws.

Additional key findings include:

  • RMLs lead to a decrease in maternal hospitalization involving a tobacco use disorder diagnosis, yielding a net zero effect over maternal hospitalizations involving any substance use disorder after RML.
  • RMLs were not associated with statistically significant changes in newborn health, suggesting limited impacts.
  • MMLs were not associated with statistically significant changes in maternal substance use disorders nor newborn health.

The types of newborn health outcomes examined included low birth weight, low gestational age, congenital anomalies, respiratory conditions, feeding problems, neonatal drug withdrawal syndrome, fetal alcohol syndrome, and prenatal exposure to noxious substances.

“These findings are neither an endorsement nor an indictment of marijuana use. That’s for each patient and their doctor to discuss,” said Simon. “What this study tells us is evidence on the impact of the laws by looking at data close to 16 million hospital births in 34 states over years 2007-2018 as well as birth certificates in all states from 2007-2019.”

To read the full article, click here.

This was originally published by Indiana University O'Neill School of Public and Environmental Affairs. 

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