ANTENATAL CARE IN PREGNANCIES AT RISK OF ALLOIMMUNE THROMBOCYTOPENIA - REPORT OF 19 CASES IN 16 FAMILIES

Objective: To assess accuracy of a management program in patients at r isk for alloimmune thrombocytopenia (NAITP) and to describe perinatal outcomes. Study design: Nineteen fetuses at risk of thrombocytopenia w ere identified using obstetric history, HLA type of the mother and fet al phenotyping in cases where paternal heterozygozity for the offendin g antigen was present. Cordocentesis was timed according to obstetric history and performed with safety precautions to prevent haemorrhage, High dose intravenous gamma globulin (IVIG) was administered to the mo ther in cases with a fetal platelet count < 100 x 10(9)/l. Results: Th e platelet antagonisms were distributed as follows: HPA-1a in 15 patie nts, HPA-5a in two, HPA-3a in one, with one further woman who had anti bodies against a private antigen. All multigravidas (N = 18) had previ ously given birth to an infant with NAITP and two of those infants had experienced severe bleeding. Two fetuses were negative for the offend ing antigen. The median and mean platelet count at first cordocentesis was 26 and 75 x 10(9)/l respectively (range 3-276). A total of 46 cor docenteses were carried out, of which 37 were followed by platelet tra nsfusions. Bleeding complications were not observed. IVIG was administ ered to eight mothers and two fetuses responded. Nine infants were del ivered by caesarean section (CS) and 10 vaginally at a mean gestationa l age of 37 weeks (range 34-41). The median and mean platelet count at birth was 141.5 and 140 x 10(9)/l, respectively (range 36-314). Ultra sound examination, both ante- and postnatally, revealed no intracrania l haemorrhages. There was one procedure related neonatal death and one infant suffered from convulsions in the neonatal period due to a sinu s thrombosis, possibly related to the platelet transfusions. Conclusio ns: When obstetric history is taken into account cordocentesis in NAIT P can be postponed. Safety recommendations described in this study all ow cordocentesis without bleeding complications. However, our study do es not support routine cordocentesis in patients with a history of NAI TP. Both the risks of cordocentesis, and the lack of prospective data on the magnitude of the risk of intrauterine or peripartal bleeding, s hould be considered.