D-dimer is a specific degradation product resulting from cross-linking of fibrin monomers by activation factor XIII and then hydrolysis by fibrinolytic enzymes, and is also a specific marker of the fibrinolytic process, which can effectively reflect the activity of the fibrinolytic system in vivo. D-dimer is a sensitive marker of acute thrombosis, and women have a high incidence of thrombosis after 20 weeks of gestation, which can lead to premature labor, postpartum hemorrhage, placental abruption and other pregnancy diseases, and seriously threaten the health of mother and child. The main clinical significance of D-dimer test for pregnant women is to know in advance whether there is a tendency of thrombosis, and if the D-dimer is increased, then it is necessary to use drugs to avoid this situation. When thrombosis or coagulation occurs in the body, D-dimer is significantly elevated, reflecting the presence of increased coagulation and fibrinolytic activity in the body, which is a guide to the severity of the condition. It is also important to prevent hypercoagulability, disseminated intravascular coagulation, and kidney disease in pregnant women with elevated D-dimer, which can be detected simply by drawing venous blood. It is very important for women who are not very good at coagulation or have thrombocytopenia to have a specific D-dimer test during pregnancy, so that early detection and prevention can lead to a safe and smooth delivery.