Abstract

A mild thrombocytopenia ( < 150,000 mcL) is relatively frequent during pregnancy and is the second most common haematologic abnormality after anemia.  Its frequence at the end of pregnancy is between 6.6% and 11.6%. (1) (Acta Obstetrics Gynecologic 2000 vol. 79 (9) pp. 744-749) Gestational thrombocytopenia commonly occurs in the mid-second to third trimester and typically resolves within 6  weeks postpartum, but may recur with subsequent pregnancies and is not associated with neonatal thrombocytopenia.On the contrary,in case of a thrombocytopenia  with a platelet count  < 100,000/mcL, we must suspect an ITP, and also if  developing a platelet count < 100,000/mcL early in pregnancy , with declining platelet counts as pregnancy progresses, is characteristic of a diagnosis of ITP, a platelet count of 50-80,000/mcL may also be seen in gestational thrombocytopenia and ITP may appear even during the third trimester. (2) (Blood 2013 vol. 121 (1) pp. 38-47) Immune thrombocytopenia occurs in about 1 in 1000 to 1 in 10,000 pregnancies and also if a mild ITP is indistinguishable from gestational thrombocytopenia when there is a platelet count > 70,000/mcL, the distinction between the two diseases is not important, because in any case there is no need of pharmacologic treatment with this platelet count. (3) (www.uptodate.com 2014)  Other causes of thrombocytopenia in pregnancy are thrombocytopenias associated with systemic disorders such as severe pre-eclampsia (15-20%), the HELLP syndrome (hemolysis, elevated liver enzymes, low platelets) (< 1%), AFLP (acute fatty liver of pregnancy) ( < 1%). Other causes non pregnancy specific, will be discussed in the section on “Pathogenesis”. 
A basic laboratory evaluation of thrombocytopenia in pregnancy include a complete blood count (CBC), a reticulocyte count, a peripheral blood smear examination, liver function tests, a viral screening (HIV, HCV, HBV). Other tests to be considered only if clinically indicated, are antiphosphoplipid antibodies, anti-nuclear antibodies, thyroid function tests, H.pylori testing; in case of suspected DIC are required PT, PTT, Fibrinogen, fibrin split products; a von Willebrand type IIB testing is required if there is a history of bleeding and a family history of thrombocytopenia; a direct Coombs test is required if is suspected an autoimmune thrombocytopenia in case of presence of anemia and reticulocytosis (Evans Syndrome), a dosage of immunoglobulins if, because of recurrent infections, a Common Variable Immune Deficiency (CVID) is suspected. (4) (American Society of Hematology (ASH)  guidelines, quick reference 2013)
Women without bleeding manifestations and a platelet count > 30,000/mcL do not require any treatment until 36 weeks of gestation, but if there are clinically relevant bleedings or if the platelet count is < 30,000/mcL, as first line of treatment can be used glucocorticoids or IV IG. In pregnancy can be used prednisone or prednisolone, but not dexamethasone that crosses the placenta more readily. The dosage of IV IG recommended is 1 gr./kg and the dosage of prednisone recommended in the guidelines of the American Society of Hematology is 1 mg/kg daily (5) (Blood 2011 vol. 117 (5) pp. 4190-4207), but other experts recommended a lower dose of 0.25 to 0.5 mg/kg daily. Combined corticosteroids and IV IG can be used as second line treatment. Splenectomy is generally avoided during early pregnancy because may increase the risk of fetal death and premature labor, and during later pregnancy because may be technically challenging due to uterine enlargement. (3) (www.uptodate.com 2014) The safety of rituximab and of thrombopoietin receptor agonists, romiplostim and eltrombopag, in pregnancy, are unknown.The use of some other agents used in ITP such as dapsone and cyclosporine is not recommended, the use of other agents such as anti-D immunoglobulin and azathioprine is relatively contraindicated and the use of other agents such as danazol, vinca alkaloids, cyclophosphamide and mycophenolate mofetil is absolutely contraindicated in pregnancy. (4) (American Society of Hematology (ASH) guidelines, quick reference 2013) 

  
 References  :

1 ) Sainio S., Kekomaki R., Riikonen S. et al.  : Maternal thrombocytopenia at term : a population-based study. Acta Obstetrics Gynecologic 2000; 79 (9) : 744-749
2 ) Gernsheimer Terry., James Andra H., Stasi Roberto  : How I treat thrombocytopenia in pregnancy. Blood 2013; 121 (1) : 38-47
3 ) George James N.,Knudtson Eric J.,Leung Lawrence L.K. et al. : Thrombocytopenia in pregnancy.www.uptodate.com 2014)
4 ) Rajasekhar Anita, Gernsheimer Terry, Stasi Roberto et al.  : Quich Reference, 2013 clinical practice guide on thrombocytopenia in pregnancy, American Society of Hematology
5 ) Neunert C., Li W., Crowther M., et al.  : The American Society of Hematology 2011 evidence-based practice guidelines for immune thrombocytopenia. Blood 2011; 117 (16) : 4190-4207

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