Prevalence of Xylazine in Umbilical Cord Tissue, October 2023-September 2024

Author(s): Kari M. Midthun Ph.D., F-ABFT*, Alexandria A. Reinhart, Ph.D., NRCC-CC

In utero drug exposure is a significant public health concern for developing fetuses and neonates. Confirmation of prenatal drug exposure often relies on toxicological testing of neonatal specimens, with umbilical cord tissue (UCT) rapidly becoming the preferred matrix. Interpretation of neonatal results can be challenging when findings contain drugs commonly administered during labor and delivery, such as fentanyl, benzodiazepines, and opiates/opioids. Xylazine, a toxic adulterant increasingly found in the illicit fentanyl drug supply, can serve as a marker to differentiate between medical and illicit exposure. This study sought to determine the prevalence of xylazine in UCT testing over a 12-month period (October 1, 2023-September 30, 2024). Within one year, xylazine was reported in 2.1% (n=248) of all UCT cases positive for any drug finding and remained at consistent positive rates over the course of the 12 months (1.8-2.3% quarterly). Most samples were positive for both xylazine and fentanyl, with additional polydrug combinations commonly containing stimulants, including methamphetamine and/or cocaine. This study reports the positive detection of xylazine in neonatal UCT and highlights the need for continued study of drug trends in the neonatal population.