Fetal and neonatal alloimmune thrombocytopenia (FNAIT)

Version: 3.1
Published: 30 November 2023
Condition for which Ig has an established therapeutic role.

This indication relates only to prevention or treatment of fetal thrombocytopenia or haemorrhage. Neonates with neonatal alloimmune thrombocytopenia (NAIT) are eligible under the indication for prevention or treatment of neonatal thrombocytopenia or haemorrhage.
 

• Evidence of fetal thrombocytopenia
• OR
• Evidence of spontaneous fetal haemorrhage

Where fetal blood sampling demonstrates there has been a failure to improve the platelet count, national guidelines recommend the consideration of intrauterine platelet transfusion rather than further Ig therapy.

Ref: Patient Blood Management Guidelines – Module 6 –Neonatal and paediatric (Section 4.2)

This indication relates only to prevention or treatment of fetal thrombocytopenia or haemorrhage. Neonates with NAIT are eligible under the indication for prevention or treatment of neonatal thrombocytopenia or haemorrhage.
 

• Unexplained previous fetal death or previously affected sibling
• AND
• Maternal platelet-specific alloantibodies known or suspected to cause this condition (most commonly HPA-1a or HPA-5b)

Where fetal blood sampling demonstrates a failure to improve the platelet count, national guidelines recommend the consideration of intrauterine platelet transfusion rather than Ig therapy.

(Ref: Patient Blood Management Guidelines – Module 6 –Neonatal and paediatric (Section 4.2)

This indication relates only to prevention or treatment of neonatal thrombocytopenia or haemorrhage. Pregnant women with FAIT are eligible under the indication for prevention or treatment of fetal alloimmune thrombocytopenia.
 

• Evidence of thrombocytopenia <30 x 10⁹/L in a neonate with NAIT or where a diagnosis of NAIT is highly suspected
• OR
• Evidence of thrombocytopenia <30 x 10⁹/L in offspring of a mother with ITP

This indication relates only to prevention or treatment of fetal alloimmune thrombocytopenia.  Neonates with NAIT are eligible under the indication for prevention or treatment of neonatal thrombocytopenia or haemorrhage. 
 
Review is not mandated for this indication however the following criteria may be useful in assessing the effectiveness of therapy.
 

• Fetal or neonatal morbidity or mortality in the context of maternal alloantibodies
• AND
• Occurrence and severity of thrombocytopenia in the neonate

Neonates with NAIT are eligible under the indication for prevention or treatment of neonatal thrombocytopenia or haemorrhage.
 

This indication relates only to prevention or treatment of fetal alloimmune thrombocytopenia.  Neonates with NAIT are eligible under the indication for prevention or treatment of neonatal thrombocytopenia or haemorrhage.

Review is not mandated for this indication however the following criteria may be useful in assessing the effectiveness of therapy.

 

• Fetal or neonatal morbidity or mortality in the context of maternal alloantibodies
• AND
• Occurrence and severity of thrombocytopenia in the neonate

This indication relates only to prevention or treatment of neonatal thrombocytopenia or haemorrhage. Pregnant women with FAIT are eligible under the indication for prevention or treatment of fetal alloimmune thrombocytopenia.

Review is not mandated for this indication however the following criteria may be useful in assessing the effectiveness of therapy.
 

• Occurrence and severity of thrombocytopenia in the neonate
• AND
• Maximum platelet count achieved within seven days of Ig treatment

• Dose during pregnancy (IVIg) - 1 g/kg (up to a maximum maternal weight of 100 kg) weekly throughout pregnancy. Other doses and schedules have been used and some studies have used IVIg in conjunction with steroids.

• Dose during pregnancy (IVIg) - 1 to 2 g/kg (up to a maximum maternal weight of 100 kg) weekly throughout pregnancy, with starting time and dose tailored to individual risk profile and history.
  Pacheco et al, 2011 recommends Ig treatment (at times in conjunction with steroids):
   

  • Previous infant with thrombocytopenia but no intracranial haemorrhage – from 20 weeks at 1 to 2 g/kg, increasing to 2 g/kg at 32 weeks until birth;
  • Previous fetus or neonate with intracranial haemorrhage diagnosed at 28 or more weeks gestation – from 12 weeks at 1g/kg; 1 to 2 g/kg from 20 weeks, increasing to 2 g/kg from 28 weeks until birth;
  • Previous fetus or neonate with intracranial haemorrhage diagnosed at less than 28 weeks gestation - from 12 weeks at 2 g/kg until birth;

• Neonatal dose (IVIg) - 1 g/kg. Occasionally more than one dose is required if thrombocytopenia persists.