Objective To investigate the diagnosis, prenatal treatment and prognosis of pregnancy with idiopathic thrombocytopenic purpura(ITP).Methods The clinical data of 92 cases of pregnancy with ITP in Beijing Obstetrics and Gy necology Hospital during Oct.1994 to Oct.2003 were analysed, including the ch anges of platelet counts, bleeding improvement, and the outcome of mothers and i nfants after treatment by using glucocorticoids, gamma globulin and transfusio n of platelets. Results The incidence of pregnancy with ITP was 2.4‰. Thirty-four cases(40%) were ac companied with other complications, such as hypertensive disorders complicating pregnancy (7), postpartum hemorrhage (6), premature labor (9), impaired glucose tolerance (19) and fetal macrosomia (10). Among the 92 cases, vaginal delivery and cesarean section were performed in 20(22%) and 72(78%) cases, respectively. Twenty-six, 18 and 24 cases were treated by glucocorticoids, glucocorticoids p lus gamma globulin, and glucocorticoids plus gamma globulin plus transfusion of platelets, respectively. Significant effects were achieved in 42 cases(62%), g eneral effects in 16 cases(24%),and improvement in 8 cases(12%),respectively. T he incidence of postpartum hemorrhage was 8%(6/72 cases). There was no maternal death.The infantile death ratio was 2/94 during perinatal period. The platele t count of peripheral blood in all the newborns was higher than 100?109/L.Th ere were no intracranial hemorrhage and other diseases related to platelet decre ase. Conclusion Glucocorticoids, gamma globulin and transfusion of platelets are effective m ethods for the treatment of ITP in mid-late pregnancy. They can increase the platelet counts and decrease the postpartum hemorrhage of the patients, and have no side effects to mother or infant.\ \