BACKGROUND: Chronic use of opioids is associated with hematologic and immunologic effects, including lymphopenia. Despite an increase in opioid use during pregnancy, little is known about the potential immunologic effects on the neonate after exposure to opioids in-utero. We aimed to evaluate the presence of lymphopenia among neonates exposed to opioids in-utero.
METHODS: We conducted a retrospective chart review of infants admitted to the neonatal intensive care unit (NICU) of a single institution after exposure to opioids in-utero. We compared the lymphocyte counts of this population to a control NICU population.
RESULTS: A higher percentage of neonates exposed to opioids in-utero were lymphopenic compared to our control population (44% vs 24%, p = 0.035).
CONCLUSIONS: This is the first study we are aware of, that investigated an association between neonatal lymphopenia and opioid exposure in-utero. Further studies to explore clinical implications of this finding are needed.