Study: Marijuana Legalization Laws Not Negatively Impacting Neonatal Health

New York, NY: State laws legalizing marijuana for either adult-use or for therapeutic purposes are not associated with adverse effects on neonatal health outcomes at the population level, according to data published in the Journal of Health Economics.

Researchers affiliated with Columbia University, the University of North Carolina, and Indiana University evaluated the influence of statewide marijuana liberalization policies on newborns’ health over a 12-year period (2007-2019). 

Investigators reported: “There is no statistically significant effect of MMLs (medical marijuana laws) on the proportion of newborn hospitalizations with prenatal exposure to noxious substances, neonatal drug withdrawal syndrome, fetal alcohol syndrome, slow growth, respiratory conditions, feeding problems, congenital abnormalities, low gestational age, low birth weight, or very low birth weight. Likewise, RMLs (recreational marijuana laws) appear to have no effect on these outcomes.”

Authors concluded, “In absolute numbers, our findings implied modest or no adverse effects of marijuana liberalization policies on the array of perinatal outcomes considered.” However, they cautioned, “Our null findings do not refute nor support an argument that prenatal exposure to marijuana has negative effects on newborn health outcomes, but rather that state marijuana liberalization policies are not associated with net changes at the population-level that are statistically detectable or economically meaningful.”

Investigators described their data as “the most comprehensive evidence to date” on the effect of legalization policies on newborns’ health.

Studies assessing the potential impacts of in utero cannabis exposure on perinatal health are inconsistent. While some observational studies have identified a link between exposure and low birth weight and/or an increased risk of preterm birth, other studies have failed to substantiate these outcomes after adjusting for confounding factors, such as tobacco smoking.

Full text of the study, “Marijuana liberalization policies and perinatal health,” appears in the Journal of Health Economics. Additional information is available from NORML’s fact sheet, ‘Maternal Marijuana use and Childhood Outcomes.’