Breastfeeding Travelers: Precautions and Recommendations

Abstract

With increased travel globally, more women travel while breastfeeding their infants as well as during pregnancy. The transfer of drugs and chemicals into human milk differs from transfer via umbilical cord during pregnancy. Because there is little evidence‐based literature on recommendations for breastfeeding travelers, we review factors that influence drug passage into breast milk and available safety data on common medications that may be encountered by breastfeeding travelers. Biologic and immunologic events in the mother may affect the breastfeeding infant. We review those that are relevant to the breastfeeding woman who is preparing to travel. We also review the use of vaccines in breastfeeding women and the mechanisms by which they could affect the infant. Physiologic changes that occur with breastfeeding involve the hormones oxytocin and prolactin. The hyperplasia of milk ducts and production of immunologically rich human milk occur through the feedback mechanism of suckling. Changes to the mother's immune system following vaccine administration should not differ from the non‐breastfeeding state, though little research has been directed to this question. Breast milk does not adversely impact the response to vaccines administered directly to the infant. 1,2 Specific antibody responses to travel‐related vaccines have not been studied in nursing mothers. Maternal plasma volume expands by 50% through pregnancy and returns to normal level in most women by 8 weeks postpartum. 3 This increases the volume of distribution of drugs administered, related to the amount of protein binding of the given compound. Although most medications transfer into human milk, many are found at low concentrations in breast milk and are relatively safe for the infant. The clinician should consider the risk of the drug versus the benefit of breastfeeding for the infant. Maternal, drug, and infant factors influence the amount of drug available to the nursing infant. The factors influencing drug … Corresponding Author: Lin H. Chen, MD, Travel Medicine Center, Mount Auburn Hospital, 330 Mount Auburn Street, Cambridge, MA 02138, USA. E‐mail: lchen{at}hms.harvard.edu