In an unusual case of fetal and neonatal alloimmune thrombocytopenia (FNAIT), maternal antibodies likely transferred through breastfeeding caused delayed thrombocytopenia in a newborn, according to results from a case study published recently in the Journal of Pediatric Hematology/Oncology.
This rare condition, which occurs when a mother’s immune system attacks fetal platelets, is typically identified before or shortly after birth. However, in this instance, the symptoms began two weeks after delivery, demonstrating the potential for breastfeeding to prolong or exacerbate FNAIT.
The patient, a healthy, full-term male, presented with petechiae at 14 days old. Subsequent testing revealed severe thrombocytopenia with a platelet count of 3,000/µL. Despite treatment with intravenous immunoglobulins and platelet transfusions, recovery was slow, taking over a month to normalize platelet levels. Analysis confirmed the mother’s anti-HPA-1a IgG antibodies in both her serum and breast milk, suggesting that these antibodies were transferred to the infant postnatally. The father and newborn were HPA-1a positive, confirming the alloimmune nature of the condition.
“It is unclear whether the breast milk anti-HPA-1a IgG antibodies actually caused the thrombocytopenia in this case, as it is believed that ingested IgG antibodies do not reach circulation in term-born infants,” the authors wrote. “Nevertheless, similar to our patient, prolonged alloimmune hemolytic disease of the newborn has been reported in breast-fed infants, including a case in which the breast milk was shown to comprise anti-rhesus D IgG antibodies without anti-rhesus D IgA antibodies.”
Read more about FNAIT signs and symptoms
FNAIT affects approximately 1 in 1,500 live births and is a leading cause of severe neonatal thrombocytopenia. Early detection is vital to avoid complications such as intracranial hemorrhage, which can lead to lasting neurological damage or death. While most cases are detected and managed during pregnancy or immediately after birth, this case highlights the need to monitor breastfed infants of mothers with known platelet incompatibility for delayed symptoms.
Unlike classic FNAIT, which typically results from maternal antibodies crossing the placenta during pregnancy, this case points to breastfeeding as a potential route of antibody transfer. The presence of anti-HPA-1a IgG antibodies in breast milk, rather than IgA antibodies as seen in other immune-mediated conditions, raises questions about their role in postnatal platelet destruction.
For patients, this case underscores the importance of close monitoring and proactive management when there is a known risk of FNAIT. Breastfeeding remains an important aspect of neonatal care, but additional research is needed to determine its role in transferring maternal antibodies that may prolong or worsen thrombocytopenia.
“Our findings suggest a potential role for breast milk in the postnatal development, maintenance, or aggravation of neonatal alloimmune thrombocytopenia, although further research is needed to confirm this hypothesis,” stated the authors.
This case provided valuable insights into the atypical progression of FNAIT and emphasized the importance of investigating breast milk as a factor in delayed neonatal symptoms. Improved understanding could lead to better prevention and treatment strategies for affected infants.
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