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A SURVEY OF THE TREATMENT OF THE PREVENTION OF NAIT IN THE UK AND IRELAND
Author(s):
Denis O'Keeffe
,
Denis O'Keeffe
Affiliations:
UHL,Dept of haematology,Limerick,Ireland
Valerie Broderick
Valerie Broderick
Affiliations:
UHL,Dept of haematology,Limerick,Ireland
(Abstract release date: 05/18/17) EHA Library. Broderick V. 05/18/17; 182818; PB2104
Valerie Broderick
Valerie Broderick
Contributions
PDF Abstract
Abstract

Abstract: PB2104

Type: Publication Only

Background
Neonatal alloimmune thrombocytopenia, (NAIT) is caused by maternal antibodies generated against alloantigens carried on fetal platelets, which cross the placenta and induce destruction of platelets in the fetus. In most cases the maternal immunisation is triggered by exposure to fetal blood at delivery. As a result, the clinical presentation tends to be more severe in subsequent pregnancies. Recent studies and guidelines have suggested that intravenous immunoglobulin (IVIG) with or without steroids can significantly reduce the severity of thrombocytopenia in subsequent pregnancies.

Aims
We set out to establish if there is consistency in the management of the prevention of NAIT across Ireland and the United Kingdom (UK).

Methods
A survey was set up on Survey Monkey and all members of the UK-Ireland Haematology group were contacted by email with a link to the survey in January 2015. In total 90 individual Specialists were contacted across 70 centres.

Results
30 responses were received to the following questions.

Who manages the prevention of NAIT in your centre? 34% of respondents stated that it was managed jointly by haematologist/feto-maternal specialists, with 26% responding it was overseen solely by haematologists and 40% solely by feto-maternal specialists.
Secondly what risk stratification each respondent used to decide risk of NAIT in the current pregnancy? 82% stated that they took into account multiple risk factors but 18% stratified risk based only on the outcome of previous pregnancy.
Thirdly how many groups do you define after risk stratification? 60% identified 3 strata of risk (standard, high and very high) with 40% classifying two risk groups (standard versus high risk).
Fourthly respondents outlined their management of a standard risk group defined as confirmed thrombocytopenia with antibody. 43% give IVIG 1g/kg weekly from 20 weeks, 28% give 1g/kg from 20 weeks increasing to 2g/kg at 32 weeks with 6% starting 1g/Kg IVIG from 24 weeks. 23% referred to feto-maternal specialist to decide IVIG . Just 20% give 0.5mg/kg of steroids from 20 or 32 weeks.
For high risk pregnancies defined as confirmed antibody positive with previous intracranial haemorrhage (ICH) after 28 weeks: 36% of centres give IVIG 1g/kg from 20 weeks, 36% give 1g/kg from 20 weeks increasing to 2g/kg at 32 weeks with 14% giving 2g/kg from 20 weeks and 14% initiating at 12 weeks. 40% gave 0.5mg/kg of steroids varying from 12-32 weeks starting.
60% of centres use a very high risk protocol (ICH before 28 weeks) with more intensive IVIG starting at 12 or 20 weeks with steroids of variable intensity and duration.
Finally respondents were questioned whether there was a planned delivery time and method for the pregnancy? 58% plan a delivery at 38 weeks with no specific delivery mode. 18% plan delivery at 38 weeks by caesarean section, 8% plan a caesarean section but with no set time and 16% have no specific protocol plan for delivery.

Conclusion
The results of this survey reveal that the optimal medical management for the prevention of NAIT, namely the medication, dosage and schedule vary widely reflecting the lack of good evidence to guide centres in this very challenging area. Based on this survey we plan with our colleagues in UKOS a prospective study of treatment and outcomes.

Session topic: 32. Platelets disorders

Keyword(s): Thrombocytopenia, Prevention, Neonate

Abstract: PB2104

Type: Publication Only

Background
Neonatal alloimmune thrombocytopenia, (NAIT) is caused by maternal antibodies generated against alloantigens carried on fetal platelets, which cross the placenta and induce destruction of platelets in the fetus. In most cases the maternal immunisation is triggered by exposure to fetal blood at delivery. As a result, the clinical presentation tends to be more severe in subsequent pregnancies. Recent studies and guidelines have suggested that intravenous immunoglobulin (IVIG) with or without steroids can significantly reduce the severity of thrombocytopenia in subsequent pregnancies.

Aims
We set out to establish if there is consistency in the management of the prevention of NAIT across Ireland and the United Kingdom (UK).

Methods
A survey was set up on Survey Monkey and all members of the UK-Ireland Haematology group were contacted by email with a link to the survey in January 2015. In total 90 individual Specialists were contacted across 70 centres.

Results
30 responses were received to the following questions.

Who manages the prevention of NAIT in your centre? 34% of respondents stated that it was managed jointly by haematologist/feto-maternal specialists, with 26% responding it was overseen solely by haematologists and 40% solely by feto-maternal specialists.
Secondly what risk stratification each respondent used to decide risk of NAIT in the current pregnancy? 82% stated that they took into account multiple risk factors but 18% stratified risk based only on the outcome of previous pregnancy.
Thirdly how many groups do you define after risk stratification? 60% identified 3 strata of risk (standard, high and very high) with 40% classifying two risk groups (standard versus high risk).
Fourthly respondents outlined their management of a standard risk group defined as confirmed thrombocytopenia with antibody. 43% give IVIG 1g/kg weekly from 20 weeks, 28% give 1g/kg from 20 weeks increasing to 2g/kg at 32 weeks with 6% starting 1g/Kg IVIG from 24 weeks. 23% referred to feto-maternal specialist to decide IVIG . Just 20% give 0.5mg/kg of steroids from 20 or 32 weeks.
For high risk pregnancies defined as confirmed antibody positive with previous intracranial haemorrhage (ICH) after 28 weeks: 36% of centres give IVIG 1g/kg from 20 weeks, 36% give 1g/kg from 20 weeks increasing to 2g/kg at 32 weeks with 14% giving 2g/kg from 20 weeks and 14% initiating at 12 weeks. 40% gave 0.5mg/kg of steroids varying from 12-32 weeks starting.
60% of centres use a very high risk protocol (ICH before 28 weeks) with more intensive IVIG starting at 12 or 20 weeks with steroids of variable intensity and duration.
Finally respondents were questioned whether there was a planned delivery time and method for the pregnancy? 58% plan a delivery at 38 weeks with no specific delivery mode. 18% plan delivery at 38 weeks by caesarean section, 8% plan a caesarean section but with no set time and 16% have no specific protocol plan for delivery.

Conclusion
The results of this survey reveal that the optimal medical management for the prevention of NAIT, namely the medication, dosage and schedule vary widely reflecting the lack of good evidence to guide centres in this very challenging area. Based on this survey we plan with our colleagues in UKOS a prospective study of treatment and outcomes.

Session topic: 32. Platelets disorders

Keyword(s): Thrombocytopenia, Prevention, Neonate

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