[Isolated thrombocytopenia in pregnancy. Etiopathogenic study and therapeutic approach in 60 patients]

We analyze the etiopathogenesis and clinical and immunohematological characteristics of 60 pregnant women with isolated thrombocytopenia (TP) (platelet count < 150 x 10(9)/l); and the frequency of TP and hemorrhagic complications in their newborn. We suggest the therapeutic approach for each maternal TP type.

We performed: clinical history, platelet count (EDTA K3, sodium citrate, microscopic exam) and investigation of antiplatelet antibodies (immunofluorescence) in all pregnant women. A familial history and ultrastructure of platelets were studied when hereditary macrothrombocytopenia (HM) was suspected. A Levine's test of homogenicity of variances was applied to compare the mean platelet count in each diagnostic group. A linear regression between maternal and newborn platelet counts was performed.

In 37 thrombocytopenic women (62%) no antiplatelet antibodies were found, and the clinical history was negative for previous TP or abnormal bleeding. Four patients (7%) were diagnosed as pseudothrombocytopenia EDTA-mediated, and eight (13%) of HM. Finally, an autoimmune etiology was suspected in 11 women (18%) and antiplatelet antibodies were detected in 9. Mean platelet counts of mother with immune TP did not show statistically significant differences with other diagnostic groups. Abnormal bleeding was not observed in any patient or newborn. There was no correlation between platelet counts of mothers and newborns. Platelet count obtained by skull bone punction led to unnecessary caesarians in four cases.

The frequency of immune thrombocytopenia in pregnant women is low (18%). There is a high prevalence of benign TP (62%). The pseudothrombocytopenias and HM are frequent findings (20%), and special care is advisable in these cases to avoid unnecessary therapeutic procedures.