PB0669 - Impact of the use of intravenous immunoglobulins and prednisone on newborns of mothers with platelet alloimmunization- a retrospective observational study

Background: Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is the most common cause of isolated severe thrombocytopenia in the fetus and neonate. The primary goal of treatment in FNAIT is to prevent intracranial hemorrhage (ICH), which occurs with an incidence of 7–26% in untreated first pregnancies affected by FNAIT. A non-invasive strategy, with a combination of prenatal injections of intravenous immunoglobulins (IVIG) and prednisone taken by the mother, is considered the optimal prenatal care in FNAIT.

Aims: The main objective of this retrospective study is to characterize and analyze the impact of the use of intravenous immunoglobulins (IVIG) and prednisone on newborns of mothers with platelet alloimmunization.

Methods: This study is a single-center retrospective observational study. The study population included all pregnant women who received immunoglobulins for platelet alloimmunization during a period of 10 years (2011-2021) as well as their newborns.

Results: A total of 23 mothers and their newborns could be listed in the databases of the CHU de Québec-Université Laval. Ten received IVIG alone since the risk of intracranial bleeding in the newborn was considered low and 13 received a combination of IVIG and prednisone. The main side effects were headache (52%) and, in women who received prednisone, the incidence of gestational diabetes and pre-eclampsia was higher (39% vs 10% and 15% vs 10% respectively). Only 2 high risk patients under treatment gave birth to newborns with platelets below 50 x 10 9/L, none of whom bled. There was 1 intracranial hemorrhage detected after birth, representing an incidence of 3.6% in our population. The platelets at birth of this newborn were 193 x 10 9/L, indicating that another cause explained the hemorrhage.

Conclusion(s): The use of IVIG and the addition of prednisone, in patients with a personal or family history of platelet alloimmunization, appears to reduce the incidence of intracranial hemorrhage in the newborn.