Neonatal Alloimmune Thrombocytopenia: A Concise Review

Adv Neonatal Care. 2021 Apr 1;21(2):115-121. doi: 10.1097/ANC.0000000000000775.


Background: Neonatal alloimmune thrombocytopenia (NAIT) is defined as an uncommon platelet disorder caused by maternal alloimmunization to human-specific antigens (HPAs) that are paternally inherited, resulting in low fetal/neonatal platelet levels and debilitating effects on the newborn. The incidence of NAIT is 1 in every 1000 live births within the United States; it is the most common cause of severe thrombocytopenia (<30 × 109/L) and intracranial hemorrhage in term newborns.

Purpose: The purpose of this article is to discuss the pathophysiology, clinical manifestations, diagnosis, and treatment of NAIT and its implications upon the lifespan of the neonate.

Methods: A literature review was conducted using PubMed, CINAHL, and Google Scholar (2014-2019). Search terms included NAIT, neonatal/fetal alloimmune thrombocytopenia, newborn platelets, and intracranial bleeding and NAIT.

Results: NAIT can affect first pregnancies and often goes undiagnosed until delivery. Universal screening tools with a focus on HPA-1a typing via noninvasive testing have been successfully trialed and have yielded promising results indicating a 75% reduction in risks associated with NAIT; however, none have been incorporated into practice and prophylactic treatment remains unavailable.

Implications for research: Adopting a universal screening tool and prophylaxis for NAIT would allow for early diagnosis and treatment in utero.

Implications for practice: Many healthcare providers are not familiar with NAIT often focusing on other causes of thrombocytopenia as a potential diagnosis.

Publication types

  • Review

MeSH terms

  • Antigens, Human Platelet*
  • Blood Platelets
  • Female
  • Fetus
  • Humans
  • Infant, Newborn
  • Pregnancy
  • Prenatal Care
  • Thrombocytopenia, Neonatal Alloimmune* / diagnosis
  • Thrombocytopenia, Neonatal Alloimmune* / epidemiology
  • Thrombocytopenia, Neonatal Alloimmune* / therapy


  • Antigens, Human Platelet