ABSTRACT
The increasing prevalence of nonprescribed fentanyl use during pregnancy presents a clinical dilemma for lactation counseling, because pharmacokinetic data on fentanyl transfer into breast milk remain limited. For families who choose it, human milk for newborns and infants is the gold standard; clinicians’ deviation from this recommendation requires a clear rationale and supporting evidence. The 2023 Academy of Breastfeeding Medicine’s clinical protocol, “Breastfeeding in the Setting of Substance Use and Substance Use Disorder” summarizes available evidence regarding substance use and breastfeeding. Building on this protocol, we synthesize existing data regarding fentanyl pharmacokinetics, breast-milk transmission, the evolving illicit opioid supply, and our clinical experience to develop guidance for scenarios that involve nonprescribed fentanyl use before the birth hospitalization. We propose a practical, harm-reduction-oriented approach: initiation of breastfeeding 72 hours after the most recent use of a nonprescribed opioid when paired with parental treatment engagement, newborn monitoring, and multidisciplinary support in the hospital setting. This approach may be supported by contingency planning for the possibility of return to nonprescribed substance use. Components of these plans include breastfeeding cessation, identification of an alternate child caregiver, and provision of developmentally appropriate non–breast-milk nutrition to the child. Clear, compassionate guidance can empower clinicians to partner with families, reduce stigma, and promote safe breastfeeding practices during the birth hospitalization in the setting of recent nonprescribed fentanyl use.