Fetal and neonatal alloimmune thrombocytopenia – The Norwegian management model

Abstract

In Norway, the management strategy for fetal and neonatal alloimmune thrombocytopenia (FNAIT) has for more than two decades differed from most other countries. The focus of this paper is to describe and discuss the Norwegian FNAIT management program. We recommend antenatal IVIg to women who previously have had a child with FNAIT-induced ICH, and usually not to HPA-1a alloimmunized pregnant women where a previous child had FNAIT, but not ICH. When deciding management strategy, we use not only the obstetric history but also the antenatal anti-HPA-1a antibody level as a tool for risk stratification. The Norwegian National Unit for Platelet Immunology (NNUPI) at the University Hospital of North Norway in Tromsø provides diagnostic and consulting service for the clinicians and the blood banks all over the country, and serves as a national reference laboratory for FNAIT investigations.

Epidemiology and management of fetal and neonatal alloimmune thrombocytopenia

“…Currently we use the clinical outcome of a previous FNAIT pregnancies for risk stratification. Some studies show that alloantibody levels could predict disease severity [57]; an approach which has been used in Norway for two decades [58]. However severe FNAIT cases have been described with low antibody titres implicating that sensitivity is low [59].…”

An HPA-1a–positive platelet–depleting agent for prevention of fetal and neonatal alloimmune thrombocytopenia: a randomized, single-blind, placebo–controlled, single-center, phase 1/2 proof-of-concept study

“…Administration of RLYB211 periodically during pregnancy is broadly similar to antenatal administration of hyperimmune anti-D IgG for the prevention of RhD immunization late in pregnancy. The administered dose of RLYB211 would be well below an exposure level of 3 IU/mL, which is the level used in Norway for risk stratification of HPA-1a-immunized pregnant women [15,50]. Based on the assumption that the distribution volume of anti-HPA-1a is 4000 mL when i.v.…”

O êxito no manejo clínico de um paciente com Trombocitopenia Neonatal Aloimune: estudo de caso

“…Na Noruega, país com melhores estudos sobre o tema, mulheres com elevados níveis de anti-HPA1a (maior ou igual a 3UI/ml) são selecionadas para cesárea eletiva por volta de 38-39 semanas em casos de primeira gestação e 37 semanas se, na gravidez anterior, houve hemorragia intracraniana. A contagem plaquetária é realizada por coleta do sangue do cordão umbilical e a transfusão realizada, se necessária, em até 30 minutos após o nascimento (TILLER H, et al, 2020).…”