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Prenatal Management of Pregnancies at Risk of Fetal Neonatal Alloimmune Thrombocytopenia (FNAIT) (Scientific Impact Paper No. 61)


What is it? Fetal neonatal alloimmune thrombocytopenia (FNAIT), also known as neonatal alloimmune thrombocytopenia (NAIT) or fetomaternal alloimmune thrombocytopenia (FMAIT), is a rare condition which affects a baby’s platelets. This can put them at risk of problems with bleeding, particularly into the brain. One baby per week in the UK may be seriously affected and milder forms can affect one in every 1000 births.

This paper considers the latest evidence in relation to treatment options in the management of pregnancies at risk of FNAIT. Specifically, we discuss the role of screening, when IVIg should be started, what dose should be used, and what evidence there is for maternal steroids. We also consider in very rare selected cases, the use of fetal blood sampling and giving platelet transfusions to the baby before birth. Finally, we consider the approaches to blood testing mothers to tell if babies are at risk, which is offered in some countries, and development of new treatments to reduce the risk of FNAIT.

COVID disclaimer

This Scientific Impact Paper was developed prior to the emergence of the COVID-19 coronavirus.

Version history

This is the first edition of this paper. Please note that the Scientific Advisory Committee regularly assesses the need to update. Further information on this review is available on request.

Developer declaration of interests

Dr F Regan, Imperial College Healthcare NHS Trust, London: None declared.

Mr CC Lees MRCOG, London: None declared.

Dr B Jones MRCOG, London: None declared.

Professor KH Nicolaides FRCOG, London: None declared.

Mr RC Wimalasundera FRCOG, London: None declared.

Dr A Mijovic, King’s College Hospital, London: None declared.

This page was last reviewed 10 April 2019.