THC was the most common substance detected in newborn drug screening at an Arkansas hospital, found in 64% of positive results, and THC-positive rates increased significantly over the study period, particularly after state legalization.
Obstetricians, neonatologists, public health officials, and policymakers evaluating prenatal substance use trends.
What the researchers found
Among 450 positive meconium drug screens, THC was most common (64.2%), followed by amphetamines (11.1%) and opioids (6.7%). The adjusted positive rate increased from 6.8% to 7.4% over 2018-2023. THC use increased more than other substances and the increase accelerated after state legalization. Infants with positive screens had lower birth weight, height, head circumference, and longer hospital stays.
Why it matters
Prenatal THC exposure is increasing alongside legalization, and this study documents measurable adverse neonatal outcomes. The acceleration of THC use after legalization adds urgency to the need for prenatal screening and intervention.
The numbers in context
8,030 live births, 957 screened, 450 positive (47%). THC: 64.2% of positives. Adjusted positive rate: 6.8% to 7.4% over study period. 17.8% positive for multiple substances. Smoking mothers: OR 2.39 for positive MDS.
How the study worked
Retrospective analysis of 957 mother-infant dyads with meconium drug screen results from 8,030 live births at a reference hospital in Arkansas (2018-2023). An adjusted monthly positive rate accounted for variable screening rates.
What this study cannot tell us
Non-universal screening means true prevalence is unknown. Screening was provider-initiated, introducing selection bias. Cannot control for confounders like poverty, nutrition, and other substance use that accompany THC-positive results. Single hospital in one state.
How to read the evidence
Reasonable sample with adjusted rate calculation to account for variable screening, but non-universal screening and single-site design limit generalizability.
When this study was published
2025 publication with 2018-2023 data.
The bigger picture
Cannabis is increasingly perceived as safe during pregnancy, partly because of normalization through legalization. This study shows that prenatal cannabis exposure continues to rise and is associated with measurable adverse birth outcomes, even in a state that only recently legalized.
Questions still open
- Would universal prenatal substance screening change intervention opportunities?
- How much of the THC increase is due to legalization versus changing reporting or detection methods?
Common questions
Is cannabis use during pregnancy harmful?
Did legalization increase prenatal cannabis use?
Read the original research
Evaluating maternal drug use disparities, risk factors and outcomes in Northeast Arkansas: a pre, during, and post-COVID-19 pandemic analysis.
BMC public health, 25(1), 509
Citation
Gomez Pomar, Enrique; Berryhill, Johnna; Bhattacharyya, Sudeepa. (2025). Evaluating maternal drug use disparities, risk factors and outcomes in Northeast Arkansas: a pre, during, and post-COVID-19 pandemic analysis.. BMC public health, 25(1), 509. https://doi.org/10.1186/s12889-025-21636-4
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