Background: A prospective study of Thrombocytopenia during pregnancy: an institutional based prospective study of 6 month Methods: It was a prospective 6 month study of pregnancy with thrombocytopenia to study the cause of thrombocytopenia and in which period of gestation these patient was diagnosed,and how much patient have severe thrombocytopenia . Results: among 3790 deliveries, total 100 women were having thrombocytopenia. Commonest etiology was gestational thrombocytopenia 66% .70%patient have mild thrombocytopenia, 18%moderate and 12%patient have severe thrombocytopenia. 37% patient diagnosed at 21– 28 week POG and 38% patient diagnosed at 37–42 week POG. Conclusions: Thrombocytopenia in pregnancy may occur secondary to a variety of causes. Most of these cases occur during specific periods of gestation.Most of these have mild thrombocytopenia and conservatively manged.