ANTENATAL MANAGEMENT OF FETOMATERNAL ALLOIMMUNE THROMBOCYTOPENIA - REPORT OF 15 AFFECTED PREGNANCIES

The recognition that spontaneous intracranial haemorrhage (ICH) may oc cur in utero in fetomaternal alloimmune thrombocytopenia (FMAIT) led u s to attempt to prevent this in 15 pregnancies of 11 women who had pre viously affected infants with FMAIT due to anti-HPA-1a. The antenatal management included fetal platelet transfusions and maternal steroids and/or high-dose intravenous immunoglobulin (IVIgG). In the first preg nancy, ICH occurred between 32 and 35 weeks' gestation before any trea tment had been given, emphasizing the need for earlier intervention. F ive of the 14 subsequent pregnancies in this study were considered to be severely affected (severe haemorrhagic complications in a previous infant and initial fetal platelet count < 20 x 10(9)/L in this study); four were managed successfully with weekly fetal platelet transfusion s started between 18 and 29 weeks and continued until delivery at 33-3 5 weeks, and one severely affected case who was referred at 36 weeks w as managed successfully with a single platelet transfusion prior to de livery. Five pregnancies were considered to be mildly affected (previo us infants were unaffected by severe bleeding and initial fetal platel et count > 50 x 10(9)/L in this study). The platelet counts were maint ained in one case with steroids and in three with IVIgG without the ne ed for repeated platelet transfusions, but in the fifth the fetal plat elet count fell despite steroids and IVIgG and serial platelet transfu sions were required. Four pregnancies were unsuccessful; two pregnanci es were terminated after severe ICH occurred at an early stage before fetal blood sampling had been carried out, one fetus died after the mo ther had a severe fall despite the successful initiation of fetal plat elet transfusions and one died due to a cord haematoma which occurred at the time of the initial fetal blood sampling. The optimal managemen t of FMAIT to reduce the risk of antenatal ICH remains uncertain. Ster oids and IVIgG may be effective in some mildly affected cases but seri al fetal platelet transfusions are the preferred therapy for those who are severely affected.