Prenatal exposure to fentanyl may lead to neonatal abstinence syndrome (NAS), a constellation of symptoms observed when newborns begin withdrawing from addictive substances such as opioids. The use of umbilical cord (UC) tissue segments for newborn toxicology has been increasing due to its apparent long detection window, sensitivity, and ease of collection. However, very little has been reported in the literature concerning the prevalence of in utero exposure to fentanyl and coexposure to other

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