A high D-dimer indicates the presence of increased coagulation and fibrinolytic activity in the body. If there is activated thrombosis or fibrinolytic activity in the blood vessels, D-dimer will be elevated. Increased D-dimer is seen clinically in a variety of diseases, such as hypercoagulable states, kidney disease, organ transplant rejection, etc. For women, D-dimer may be higher than normal during pregnancy, but there is no normal reference range for D-dimer during pregnancy. If abnormally high D-dimer is found during maternity checkup, we should be alert to the occurrence of hyperemesis and pre-eclampsia, because high D-dimer indicates hypercoagulability in the body, and hypercoagulability will cause the formation of small local emboli in the placenta, which will prevent the embryo from getting the corresponding nutritional source and even affect the embryo. This may prevent the embryo from receiving the corresponding source of nutrition and even affect the fetus’ lack of oxygen, which may eventually lead to fetal death. Therefore, it is important to closely monitor the changes in blood pressure and D-dimer, especially in the second trimester. In conclusion, abnormally high D-dimer levels found during maternal checkups indicate hypercoagulable state in the body, which should alert to the occurrence of hyperemesis and pre-eclampsia, so the changes in D-dimer and blood pressure should be closely monitored, and the formation of venous thrombosis should be alerted after delivery.