Doctors across the United Kingdom generally agreed on how to treat fetal and neonatal alloimmune thrombocytopenia (FNAIT), but a new survey revealed that opinions varied on exactly when to start therapy during pregnancy, according to results of a recent survey presented by Asha Aggarwal of Oxford University Hospital at the European Hematology Association 2025 Congress in Milan, Italy, June 12 to 15.
These results suggest that while patients are largely receiving consistent care, the lack of consensus on timing may affect both clinical outcomes and healthcare costs. FNAIT is a rare but serious condition in which a pregnant person’s immune system attacks the platelets of the developing fetus, which can lead to dangerous bleeding, including bleeding in the brain.
“This is the first survey of UK practice in the antenatal management of patients with a history of FNAIT,” explained Aggarwal. She continued, “A strength of this survey is the high response rates from fetal medicine centres, but is limited by looking only at expert clinicians in fetal medicine centres, when we [are] aware that some patients are managed in smaller regional hospitals.”
For patients with a history of FNAIT in a previous pregnancy, the most common method is to begin weekly intravenous immunoglobulin (IVIg) between 12 and 20 weeks of pregnancy to reduce the risk of complications.
Read more about FNAIT treatment and care
A survey of 21 respondents from 16 of the UK’s 22 fetal medicine centers showed that nearly all specialists, whether from hematology or maternal-fetal medicine, felt confident in managing these high-risk pregnancies. In most cases, their hospitals saw one or two new FNAIT cases per year, with 81% of patients referred from other regional centers.
Clinicians were consistent in deciding which pregnancies should receive IVIg, especially in cases where a previous child had experienced either severe bleeding or low platelet counts due to FNAIT. However, the precise week of pregnancy when treatment should begin differed between centers. Most respondents treated pregnancies affected by antibodies to HPA1a and HPA5b in similar ways, despite newer evidence suggesting HPA5b might not pose the same level of risk.
When asked how they would manage more unusual situations, such as a sister of a patient with FNAIT or a donor who tested positive for relevant antibodies, responses varied widely, highlighting gaps in current guidance for edge cases.
This first nationwide examination of how UK experts manage FNAIT during pregnancy reveals strengths in shared decision-making and care delivery, but also identifies opportunities for improvement. More consistent timing for IVIg could lead to better use of resources, reduced uncertainty for expectant parents and potentially better outcomes for babies.
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