Introduction Fetal-neonatal allo-immune thrombocytopaenia (FNAIT) is associated with significant risks (up to 79%) of intracranial bleeding. Maternal immunoglobulin is a relatively new method of preventing recurrence in a subsequent pregnancy.

Method Case notes were reviewed of pregnant women on immunoglobulin due to previous FNAIT (January 2003 to September 2009).

Results 11 pregnancies utilised immunoglobulin. One woman had four pregnancies on immunoglobulin. Six women had HLA 1a Antibodies; one HLA B7 Antibodies. Immunoglobulin was commenced between 17+2- and 20+5-week gestation, with a mean of 15 doses. Mean gestation at first cordocentesis was 30+2 weeks (range 27+6 to 36+2 weeks). Platelet count at first cordocentesis was 46×10⁹/l in one case; 50–100×10⁹/l in five cases; greater than 100×10⁹/l in five cases. Two women had two cordocenteses and two women had three. Mean delivery gestation was 34 weeks (range 28 to 37+1 weeks), with six vaginal deliveries and five Caesarean sections. One woman had an emergency Caesarean section at 28 weeks due to fetal bradycardia during cordocentesis. Two babies had platelet counts less than 50×10⁹/L at delivery (range 36–46×10⁹/l), nine babies had platelet counts greater than 50×10⁹/l (range 55–258×10⁹/l). All babies had normal cranial ultrasound scans.

Conclusion In our population, immunoglobulin prevented the serious fetal or neonatal morbidity of FNAIT. Women on immunoglobulin for previous FNAIT require cordocentesis surveillance. Monitoring fetal platelet response enables in-utero platelet transfusion in non-responders and timing and mode of delivery to be planned. A multi-centre trial of treatment regimes is required to optimise this expensive therapy.