How many weeks to administer heparin for atypical antiphospholipid syndrome is determined by the doctor depending on the patient’s condition. Injections are usually needed throughout the pregnancy. Atypical antiphospholipid syndrome is an autoimmune disease, mainly due to abnormal coagulation function, which is prone to cause fetal miscarriage in early pregnancy, and placental vascular embolism in middle and late pregnancy, thus causing intrauterine hypoxia and developmental delay of the fetus. Heparin can prevent antiphospholipid antibodies from inducing trophoblastic inflammation and trophoblastic cell death, inhibit complement activation, etc., thus preventing fetal abortion. The principle of obstetric management of atypical antiphospholipid syndrome during pregnancy is to inject low molecular heparin after ovulation before pregnancy, stop the drug without pregnancy, inject low molecular heparin during the whole pregnancy, and continue the injection for 6 to 12 weeks after delivery. The above content is only for reference, specific cases should be standardized treatment under the guidance of a doctor to avoid adverse reactions. All of the above medications should be used under the guidance of a doctor, avoid self-medication.