Rodriguez N, et al. - In this study, researchers investigated the value of salivary cortisol as an objective biomarker of withdrawal severity in opioid-exposed newborns. They conducted a prospective study in 25 full-term opioid-exposed newborns monitored for neonatal abstinence syndrome (NAS). Collection of morning and evening salivary cortisol was done; the collection started within 48 h postbirth until initiation of pharmacologic treatment for withdrawal (PreTreatment) or when the infant was discharged without pharmacotherapy (No Treatment). The PreTreatment group (n = 11) had significantly higher cortisol levels within the first week of life (median 1.74 µg/dl) than in the No Treatment group (n = 11; median 0.72 µg/dl; P = 0.003); three infants had inadequate saliva volume for cortisol assay. Infants discharged without pharmacotherapy showed significant decrease in cortisol after 72 h postbirth (≤ 72 h median 1.25 µg/dl; ≥ 72 h median 0.58 µg/dl), whereas infants subsequently treated for the severity of withdrawal continuously displayed elevated cortisol. These findings suggest the possible value of salivary cortisol in opioid-exposed newborns as an index of stress and may assist in distinguishing infants who will have a more severe clinical presentation of NAS. Such a biomarker would enable risk stratification for early treatment and discharge decisions.