1. Etiology and diagnosis of thrombocytopenia in pregnancy Combined thrombocytopenia in pregnancy can be caused by a variety of diseases, such as aplastic anemia, idiopathic thrombocytopenic purpura (ITP), hypersplenism, systemic lupus erythematosus, severe hyperemesis preeclampsia, HIV infection, drug-induced, diffuse intravascular hemolysis, thrombotic thrombocytopenia, and hemolytic uremic syndrome. Pre-existing medical history is often clearly diagnosed as a pregnancy complication. Such patients should be pregnant after the disease is stabilized or in remission, but during the pregnancy period the disease still needs to be closely monitored and the treatment plan should be adjusted at any time if deterioration is detected. Pregnancy-onset thrombocytopenia is often detected with the onset of pregnancy comorbidities and complications, such as severe hyperemesis, and some pregnancy comorbidities such as aplastic anemia and systemic lupus erythematosus, which can occur and worsen with the progress of pregnancy. Those without clinical symptoms are often detected during routine prenatal examinations. For peripheral platelet count <100×109/L, in addition to the automatic count, it must be reviewed by traditional microscopy, and the number and morphology of erythrocytes and leukocytes must be observed, and hemoglobin must be measured. When the rechecked platelet count is <70×109/L, laboratory errors and gestational thrombocytopenia need to be excluded for etiologic diagnosis. Diagnosis can be made by taking medical history, general physical examination, peripheral blood smear, bone marrow aspiration and other laboratory tests. For thrombocytopenia found before delivery or emergency surgery, often due to time and conditions, only symptomatic treatment is done, but those who have conditions should continue to follow up after delivery to clarify the diagnosis. 2.Management of thrombocytopenia in pregnancy The management of thrombocytopenia in pregnancy focuses on the treatment of comorbidities and complications, prevention of bleeding tendency due to severe thrombocytopenia, and strengthening of fetal monitoring. According to the gestational age and platelet count, platelet count ≥50×109/L, or early pregnancy platelet count (30-50)×109/L, without bleeding tendency, often do not need special treatment. If the platelet count is <20×109/L and there is a clinical tendency to bleed, or if the platelet count is <50×109/L in the middle or late stages of pregnancy, especially before delivery or when there is an expected risk of bleeding (e.g. surgery, anesthesia, etc.), active treatment should be given. Commonly used in the treatment of thrombocytopenia: (1) Glucocorticoids: The main mechanism is to inhibit antibody production, inhibit antigen-antibody reaction, reduce excessive platelet destruction; improve capillary fragility; and stimulate bone marrow hematopoiesis. Glucocorticoids are the drugs of choice for the treatment of ITP, SLE and some cases of reoccurrence. (2) Immunoglobulin: High-dose gammaglobulin inhibits autoantibody production, inhibits crystallizable fragment receptors of monocytes and macrophages, reduces or prevents platelets from being phagocytosed, thus rapidly increasing platelet count, and can be used for those who do not respond to hormone therapy, patients with severe thrombocytopenia with bleeding tendency and severe hyperemesis (3) supportive therapy: platelet count <10×109/L, bleeding tendency, or platelet count <50×109/L during delivery or surgery, combined with severe anemia and hypoproteinemia, component transfusion such as fresh blood, platelets, fresh frozen plasma, human albumin. Because platelets have a short survival time in the body and are prone to produce homologous antibodies, making subsequent transfusions gradually ineffective, blood transfusions should be minimized during pregnancy; (4) Other: use hemostatic drugs when there are bleeding symptoms, and in patients with reanemia who have severe anemia, testosterone propionate or Anxon can be used to stimulate hematopoietic function when the male fetus is confirmed by ultrasound, and splenectomy can cause preterm delivery and infection, so try to avoid it before pregnancy. Immunosuppressants such as azathioprine are toxic to the fetus and should be used with caution. 3, the choice of delivery mode The mode of delivery for thrombocytopenic pregnant women is still controversial. For those who recommend cesarean delivery, the main reason is to prevent intracranial hemorrhage due to excessive maternal exertion or intracranial hemorrhage during delivery due to neonatal thrombocytopenia. Our experience is that vaginal delivery can be considered when the platelet count is ≥50×109/L without obstetric complications, and soft birth canal injury should be avoided as much as possible during delivery, with careful examination and thorough hemostasis to prevent postpartum hemorrhage and soft birth canal hematoma formation, and cesarean delivery can be considered when the platelet count is <50×109/L. Choose the operation day, prepare adequate blood supply, and input platelet suspension 2h before operation to make platelet count reach 50×109/L as much as possible. Intraoperative and postoperative platelet suspension can be transfused again according to the situation to keep short-term platelet elevation to prevent epidural hematoma, incisional bleeding, uterine bleeding, intracranial bleeding and organ bleeding during and after operation. Use adjuvant hemostatic drugs postoperatively. 4, neonatal management The newborn is closely monitored after birth, observed for bleeding tendency, and continuous monitoring of platelet count, platelet count related to immune factors, platelet antibodies in the maternal circulation can enter the fetal circulation through the placental barrier, destroying fetal platelets, neonatal thrombocytopenia occurs, but mostly temporary, with the level of antibodies in the body decreases, platelet count generally in the postnatal 2 ～The platelet count usually returns to normal in the first 2 to 3 months of life, but children with persistent and severe thrombocytopenia should be referred to pediatrics for treatment.