Treatment approaches of fetal and neonatal alloimmune thrombocytopenia (FNAIT) in the postnatal period vary between countries, highlighting the need for evidence-based guidelines, according to a retrospective cohort study published in Lancet Hematology.

“Quantitative evidence supporting postnatal treatment in FNAIT is sparse and there is no international consensus on neonatal management,” the authors wrote. The aim of this study was to describe contemporary management across international centers and evaluate outcomes among patients with FNAIT.

This retrospective cohort study evaluated data from 408 live-born neonates with FNAIT entered into an international registry between 2010 and 2020. The key outcomes were type of postnatal treatment and other outcomes included median platelet counts in the first week of life, median platelet count increment after transfusions, and the rates of mild or severe bleeding.

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Postnatal treatment strategies for FNAIT varied between countries. Overall, platelet transfusions were administered among 53% of neonates. Among the not treated neonates, 47% of mothers received treatment antenatally.

The use of HPA-unmatched platelet transfusions was most frequent in the United States at 75% and Slovenia at 37%, followed by 30% in Australia, 24% in Spain, 23% in Sweden, 16% in the Netherlands, and 9% in Norway. HPA-matched transfusions were most common in Norway at 48% and the Netherlands at 31%, but was substantially less common in other European countries and not used in the United States.

No treatment was most common in Sweden and Slovenia at 58% each, followed by 50% in Australia, 42% each in the Netherlands and Spain, 25% in Norway, and 13% in the United States.

The administration of HPA-matched or unmatched platelet transfusions resulted in different levels of platelets. Neonates treated with HPA-matched transfusions demonstrated a median platelet increment of 98 x 109 platelets/L compared with 59 x 109 platelets/L with HPA-unmatched transfusions (P <.0001). However, this difference resolved within 3 days and the median platelet count of neonates at day 4 after HPA-matched or HPA-unmatched transfusions was 125 x 109 and 87 x 109, respectively (P =.15).

Overall, bleeding occurred among 48% of neonates that was mild and 6% that was severe. Given the lack of consistent treatment approaches across countries, the authors concluded that “this study highlights the urgent need for further trials to established evidence-based guidelines for the management of neonates with FNAIT.”

Disclosures: This study was funded by Process and Product Development Diagnostic Services, Sanquin Please see the original reference for a full list of disclosures.


de Vos TW, Winkelhorst D, Arnadottir V, et al. Postnatal treatment for children with fetal and neonatal alloimmune thrombocytopenia: a multicentre, retrospective, cohort study. Lancet Hematol. Published online September 12, 2022. doi: 10.1016/S2352-3026(22)00243-5