Safe use of human milk for preterms in the context of maternal polypharmacy: a framework to improve practices

Maternal pharmacotherapy during lactation is an ongoing research field, which relies on scientific evidence, pharmacological reasoning and extrapolation to support risk-to-benefit assessment. Typically, drugs are studied individually for potential effects on a nursing infant, with limited information on the preterm infant. Polypharmacy during lactation is still poorly studied, leaving healthcare professionals without any scientific guidance when consulting on human milk safety in this scenario. When focusing on a dyad of a postpartum mother on polypharmacy and a preterm infant, the benefits of mother's own milk (MOM) should be weighed against the unknown potential risks of polypharmacy during lactation. Within this setting of limited evidence, a framework to improve clinical and research practices is provided. Possible measures to minimize the risk of maternal (poly)pharmacy to the newborn include: multi-disciplinary prenatal counseling; preferring medications with low passage rate into human milk; relative rating of medications according to safety profile; and 'mixed feeding' (alternating between MOM and other types of feed, preferably donor human milk). These measures can be used to support shared informed decisions on the risk-to-benefit assessment. As the topic of polypharmacy during lactation is still poorly explored, a research agenda is suggested. IMPACT: Polypharmacy during lactation is poorly studied, and practical, evidence-based guidelines for healthcare professionals are lacking. Various methods can be employed to reduce exposure to medications through human milk, even more so when applied concomitantly: preference of medications with low passage into human milk, relative rating of medications according to known safety profile, or 'mixed feeding' where mother's own milk is alternated with other types of feed, preferably donor human milk. A framework to improve clinical and research practices on provision of human milk in the setting of maternal polypharmacy and prematurity as an added challenge is provided.