Lactation professionals often encounter infants with neonatal jaundice. A subset of these cases involves a positive direct Coombs test, indicating an immune-related cause of jaundice due to blood-type incompatibility. Understanding this scenario is key to supporting breastfeeding while the infant undergoes jaundice treatment.
What a Positive Direct Coombs Test Means
A positive direct Coombs (direct antiglobulin) test detects foreign maternal IgG antibodies attached to the infant’s red blood cells (Stanford Medicine). In practice, this usually signifies antibody-mediated hemolysis caused by maternal-newborn blood group incompatibility (Stanford Medicine). Rh incompatibility and ABO incompatibility are the most common causes (Stanford Medicine). For example, a type O mother may have anti-A/B antibodies that attack an infant’s type A or B red cells, leading to hemolysis. ABO incompatibility is typically less severe than Rh disease and usually manifests as neonatal jaundice with mild anemia (Stanford Medicine). In essence, a positive Coombs test means the newborn’s jaundice is due to hemolytic disease of the newborn, rather than simple physiologic or breastfeeding jaundice.
Coombs-Positive Hemolysis and Neonatal Jaundice
When maternal antibodies coat and destroy the infant’s red blood cells, the increased breakdown of hemoglobin produces excessive bilirubin. This overloads the newborn’s still-maturing liver, causing hyperbilirubinemia and visible jaundice. Coombs-positive hemolytic jaundice often arises early (within the first 1-2 days of life) and can be more pronounced than typical physiologic jaundice. Such infants have a higher risk for significant bilirubin elevation and may require interventions like phototherapy (Stanford Medicine). However, not every Coombs-positive infant develops severe jaundice—individual factors and the degree of hemolysis influence bilirubin levels (Stanford Medicine). Clinicians monitor bilirubin trends closely, as hemolytic jaundice can escalate the risk of kernicterus if untreated. Prompt treatment (most often phototherapy) helps break down bilirubin, while addressing the underlying hemolysis (e.g. administering IV immune globulin or exchange transfusion in severe Rh disease) is sometimes necessary. Importantly, the jaundice in these cases is caused by blood-type incompatibility, not by breastfeeding itself, which means breastfeeding can usually safely continue.
Supporting Breastfeeding in Coombs-Positive Jaundice
Lactation specialists play a crucial role in helping mothers continue breastfeeding while the infant is treated for jaundice. The American Academy of Pediatrics recommends continuing breastfeeding in jaundiced infants (Kemper et al., 2022), as breast milk provides optimal nutrition and hydration. Here are key strategies for supporting breastfeeding during phototherapy or other jaundice treatments:
Encourage Frequent Feeding
Advise mothers to breastfeed at least 8–12 times per 24 hours. Frequent feeds improve the infant’s hydration and caloric intake, which in turn helps lower bilirubin levels by promoting stooling and bilirubin excretion (CDC, 2025). Early and frequent feeding is especially important in the first days of life to prevent dehydration and high bilirubin peaks.
Breastfeed During Phototherapy
Whenever possible, babies under phototherapy should be allowed to breastfeed on demand. Many hospitals use phototherapy lights or bilirubin blankets in a way that permits brief interruptions for feeding without significantly reducing treatment efficacy. The infant can be taken out of the isolette or phototherapy unit for feeds, or a fiber-optic bili-blanket can be used so that phototherapy continues during nursing. Continuing skin-to-skin contact and breastfeeding during treatment helps maintain the mother’s milk supply and comforts the baby. Clinical guidelines affirm that phototherapy can be effectively delivered while full breastfeeding continues (Flaherman et al., 2017).
Monitor Intake and Supplement if Needed
Jaundiced newborns—especially those with hemolysis—may be sleepy or feed less effectively. Monitor the infant’s weight, hydration status, and milk transfer closely. If intake is suboptimal, supplemental feeds may be indicated on a short-term basis (e.g., expressed breast milk or formula) (CDC, 2025). Any supplementation should ideally be with the mother’s pumped milk to provide ongoing breast milk benefits. According to AAP guidance, mothers might temporarily offer expressed milk by bottle or syringe after nursing sessions, or nurses may supplement with formula if the baby is not getting enough at the breast (Kemper et al., 2022). The decision to supplement should be made case-by-case, weighing the infant’s bilirubin level and feeding effectiveness (CDC, 2025).
Maintain Milk Supply
In the rare instance that breastfeeding must be interrupted (for example, during an exchange transfusion or if phototherapy requires extended separation), ensure the mother continues regular milk expression. Pumping or hand expressing every 2–3 hours will protect her milk supply until the baby can resume direct breastfeeding (CDC, 2025). Even if direct breastfeeding is temporarily paused, the baby can be fed the expressed breast milk. This way, the infant still receives the benefits of breast milk, and the mother’s lactation is sustained.
Educate and Reassure the Family
Take time to explain to parents that the jaundice is due to the baby’s red blood cells being attacked by maternal antibodies (e.g., from an ABO blood type mismatch), not from anything in the breast milk. This distinction helps alleviate any guilt or pressure the mother may feel about her milk. Emphasize that breast milk is not only safe but beneficial for a jaundiced baby—providing optimal nutrition and helping to clear bilirubin through bowel movements. Reassure the family that continuing to nurse is usually the best course, and that temporary treatments like phototherapy are common and compatible with breastfeeding (Kemper et al., 2022). Encouraging the mother and reducing any anxiety can improve let-down and overall breastfeeding success. Also, coordinate with the healthcare team to ensure the mother and baby have opportunities for skin-to-skin contact and feeding even during hospital-based treatments. A supported, well-informed mother is more likely to persevere with breastfeeding throughout the infant’s jaundice management.
Conclusion
A positive direct Coombs test in a newborn signifies immune-mediated hemolytic jaundice, often from ABO or Rh incompatibility, leading to increased bilirubin levels (Stanford Medicine). This condition frequently necessitates phototherapy to protect the infant from high bilirubin, but it does not contraindicate breastfeeding. On the contrary, sustained breastfeeding—with vigilant lactation support—is crucial in these cases. By promoting frequent feeds, managing any feeding difficulties, and keeping the mother-infant dyad together as much as possible, lactation professionals help ensure the baby continues to receive the benefits of breast milk while efficiently clearing the excess bilirubin (CDC, 2025). An educated, collaborative approach enables successful breastfeeding even as the newborn undergoes treatment for Coombs-positive jaundice, ultimately supporting both infant health and maternal confidence.
References
Centers for Disease Control and Prevention. (2025, February 14). Jaundice and breastfeeding: Breastfeeding special circumstances. U.S. Department of Health and Human Services.
Flaherman, V.J., Maisels, J., and the Academy of Breastfeeding Medicine. (2017). ABM clinical protocol #22: Guidelines for management of jaundice in the breastfeeding infant ≥35 weeks’ gestation. Breastfeeding Medicine, 12(5), 250–257. https://www.bfmed.org/assets/DOCUMENTS/PROTOCOLS/22-jaundice-protocol-english.pdfhttps://www.cdc.gov/breastfeeding-special-circumstances/hcp/illnesses-conditions/jaundice.html
Kemper, A. R., Newman, T. B., Slaughter, J. L., Maisels, M. J., Watchko, J. F., Downs, S. M., Grout, R. W., Bundy, D. G., Stark, A. R., Bogen, D. L., Volpe Holmes, A., Feldman-Winter, L. B., Bhutani, V. K., Brown, S. R., Maradiaga Panayotti, G. M., Okechukwu, K., Rappo, P. D., & Russell, T. L. (2022). Clinical Practice Guideline Revision: Management of Hyperbilirubinemia in the Newborn Infant 35 or More Weeks of Gestation. Pediatrics, 150(3), Article e2022058859. https://doi.org/10.1542/peds.2022-058859
Stanford Medicine. (n.d.). The Coombs’ test. Newborn Nursery, Stanford University School of Medicine. https://med.stanford.edu/newborns/professional-education/jaundice-and-phototherapy/the-coombs–test.html
