Embryology of the circulation

In conclusion, maternal alloantibodies against the platelet specific alloantigen HPA-1a are the most frequent cause of severe thrombocytopenia in the neonate, with an estimated incidence of one in 1100 births.Over the past two decades, confirmation of a clinical diagnosis of neonatal alloimmune thrombocytopenia by serological and genetic tests has improved greatly, allowing optimal counselling of aVected couples.Parents of an index case should receive advice on the risk of severe disease in subsequent pregnancies, and need to be given an explanation of the advantages and disadvantages of possible interventions.In serologically confirmed patients with a severe history, care should be provided by a team of fetal medicine experts, including neonatologists, haematologists, and immunohaematologists.