I think you are mistaking idiopathic thrombocytopenic purpura (ITP) for thrombotic thrombocytopenic purpura (TTP) which is a hematologic emergency (a multisystem disease that rapidly affects the neurologic, renal, and hematologic systems).
Idiopathic thrombocytopenic purpura (ITP) is the presence of isolated thrombocytopenia with a normal bone marrow and the absence of other causes to account for it. ITP is caused by increased peripheral platelet destruction, with most patients having antibodies to specific platelet membrane glycoproteins while relative marrow failure may contribute to this. There are two distinct types - acute ITP in children which has an abrupt onset and chronic ITP in adults which is gradual in its appearance.
No treatment is required when the platelet counts are more than 50,000/ml. Treatment is indicated a) when platelets are less than this and there is significant mucous membrane bleeding; b) in patients with hypertension, peptic ulcer disease or vigorous lifestyle who have a risk factor for bleeding and c) when platelet count <20,000-30,000/ml. Glucocorticoids and intra-venous gammaglobulins (I.V. Ig) are the mainstays of medical therapy. Their use and dose is dictated by the symptoms, patients clinical condition and the platelet count. Platelet transfusion is indicated for controlling severe hemorrhage.
Pregnant women require special consideration for delivery. If the platelet count is greater than 50,000/ml, the risk of serious hemorrhage is low, but steroids are started a week prior to delivery but if the platelet count is less than 50,000/ml before delivery, treatment with oral prednisone and IVIG is recommended. The effects of intravenous RhIG for ITP on an Rh(D)-positive fetus are unknown. You would need an obstetrician experienced in handling such situations as also a neonatologist for handling any problem with the newborn.