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Study breakdown

Medical marijuana legalization in Oklahoma increased neonatal THC exposure but did not change opioid exposure rates

ObservationalModerate evidence
The takeaway

After Oklahoma legalized medical marijuana, positive neonatal THC tests rose significantly from 16.2 to 22.2 per 1,000 births, but neonatal opioid exposure showed no significant change.

Neonatologists and OB-GYNs in states with evolving cannabis laws; public health researchers studying legalization effects on prenatal substance use.

Neonatal THC positives rose 37% after medical marijuana legalization

What the researchers found

Comparing 19 months before and after Oklahoma's medical marijuana law, positive THC tests in newborns increased significantly from 16.2 to 22.2 per 1,000 liveborn infants (p=0.004). Opioid exposure showed a nonsignificant decrease from 7.6 to 6.8 per 1,000 (p=0.542). The more rural site had significantly higher rates of amphetamines, benzodiazepines, and THC.

Why it matters

This study tests the specific hypothesis that medical marijuana legalization could reduce opioid use during pregnancy. While neonatal cannabis exposure increased as expected, the hoped-for reduction in opioid exposure did not materialize in a statistically significant way.

The numbers in context

16,804 live births. THC positives: 16.2 to 22.2 per 1,000 (p=0.004). Opioid positives: 7.6 to 6.8 per 1,000 (p=0.542). THC-opioid co-positives doubled from 4 to 9 cases (too few for statistical analysis). Rural site had higher rates across multiple substances.

How the study worked

Retrospective analysis of cord blood, urine, and meconium drug screens at two Oklahoma hospital sites (Oklahoma City and Lawton). 16,804 live births across 38 months (19 pre-law, 19 post-law).

What this study cannot tell us

Only two hospital sites in one state. Short 19-month comparison periods. Cannot determine whether mothers held medical marijuana cards. Small numbers for co-use analysis. No clinical outcome data for exposed neonates.

How to read the evidence

Pre-post comparison at two sites with objective drug screening data, though limited geographic scope and short time frame.

When this study was published

2024 study

The bigger picture

The increase in neonatal cannabis exposure without a corresponding decrease in opioid exposure suggests that, at least in the prenatal population, legalization may add cannabis use without substituting for opioids.

Questions still open

  • Do the cannabis-exposed neonates experience withdrawal or developmental effects? Would a longer post-legalization window show different opioid trends?

Common questions

How were neonates tested for drug exposure?
Through cord blood, urine, and meconium (first stool) screening, which can detect substance exposure during pregnancy.
Why did rural areas have higher drug exposure rates?
The study did not explain this but notes it as a finding. Rural areas may have different patterns of substance use, access to treatment, or prescribing practices.

Read the original research

Medical Marijuana Legalization in Oklahoma: Effects on Neonatal Exposure to Opiates.

American journal of perinatology, 41(S 01), e1069-e1074

Citation

DeShea, Lise; Rolfs, Shanna; McCoy, Mike; Beasley, William H; Szyld, Edgardo; Makkar, Abhishek. (2024). Medical Marijuana Legalization in Oklahoma: Effects on Neonatal Exposure to Opiates.. American journal of perinatology, 41(S 01), e1069-e1074. https://doi.org/10.1055/a-1990-8311

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