Xylazine Use in Pregnancy: A Case Report and Narrative Review

Xylazine, an alpha-2 adrenergic agonist veterinary sedative, has emerged as a frequent adulterant in illicit opioids, contributing to the ongoing "tranq dope" crisis. Its effects on human pregnancy are largely unknown, posing new challenges in obstetric addiction medicine. We present the case of a 25-year-old woman (G4P2113) with opioid use disorder who unknowingly used fentanyl adulterated with xylazine throughout pregnancy. She developed preeclampsia with HELLP syndrome, requiring urgent preterm cesarean delivery at 34 weeks. The neonate was treated for neonatal abstinence syndrome. Four days postpartum, the patient-discharged without medication for opioid use disorder-suffered intractable vomiting from withdrawal, leading to a Mallory-Weiss tear with massive hemorrhage and cardiac arrest. She required intensive care with transfusions, endoscopic hemostasis, and mechanical ventilation. Upon extubation, she disclosed fentanyl-xylazine ("tranq") use. She was transitioned to buprenorphine maintenance with supportive care for xylazine withdrawal and discharged in improved condition. We review the sparse human literature on xylazine exposure in pregnancy and relevant animal studies. Human data confirm placental transfer of xylazine, with umbilical cord assays detecting exposure, and suggest that xylazine may contribute to maternal CNS depression and neonatal sedation. Animal models demonstrate dose-dependent uterine vasoconstriction, reduced uteroplacental blood flow, fetal growth restriction, and pregnancy loss. We discuss management considerations for pregnant patients using xylazine-adulterated opioids, including challenges in diagnosis, withdrawal management, and the need for expanded harm-reduction strategies. This case and review highlight the urgent need for surveillance and evidence-based protocols to address xylazine in the perinatal setting.