THE ROLE OF PERCUTANEOUS UMBILICAL BLOOD-SAMPLING IN THE MANAGEMENT OF IMMUNE THROMBOCYTOPENIC PURPURA

On consultation, percutaneous umbilical blood sampling (PUBS) was offe red to women with immune thrombocytopenic purpura (ITP) to determine t he mode and site of delivery prior to labour. Between January 1989 and December 1993, 41 pregnant women underwent PUBS. Ah women had a histo ry of ITP, a platelet count less than 90 K, (+) antiplatelet antibody, and/or thrombocytopenia diagnosed early in pregnancy. PUBS was perfor med at term except in one patient with preterm labour, who underwent P UBS at 31 weeks' gestation. Patients with fetal platelet counts greate r than 50 K returned to their referring physician for delivery. Record s were complete in 39 pregnancies. Fetal blood was successfully obtain ed in 37 of 39 cases (95 per cent). Fetal platelet counts correlated w ith neonatal platelet counts in 36 of 37 cases (97 per cent). The inte rval between PUBS and delivery ranged from 0 to 31 days. Six of 37 fet uses (16 per cent) had significant fetal thrombocytopenia (<50 K). The se six patients underwent Caesarean section. Vaginal delivery was reco mmended in all others. There were two procedure-related complications. There were no cases of intraventricular haemorrhage in any of the neo nates. In conclusion, there is a high incidence of fetal thrombocytope nia in women with ITP. PUBS reliably detects fetal thrombocytopenia an d is therefore useful in the perinatal planning of the mode and site o f delivery.