Objective: To study the changes and clinical significance of four coagulation items, plasma fibrin (ogen) degradation products(FDP) and D-dimer in different pregnancy stages (early, middle and late), and to provide theoretical support for clinical diagnosis and treatment. Methods: The data of 200 pregnant patients in our hospital from January 2021 to December 2021 were fibrinogen, fibrinogen(FIB), prothrombin time (PT), thrombin time (TT), and activated partial thromboplastin time(APTT).The detection results of plasma fibrin (original) degradation product (fibrinogendegradationproducts, FDP) and D-dimer were also statisanalyzed. Comparative analysis of the changes of blood coagulation, FDP and D-dimer levels in the first, middle and late pregnancy stages. Results: There were significant differences in PT levels between the first, second and third trimesters (P＜0.05); there was no significant difference in TT between the first, second and third trimesters (P＞0.05); the APTT in the first trimester was significantly longer than that in the second trimester and third trimester, and the difference was statistically significant (P＜0.05); in the first trimester, the second trimester, and the third trimester, the FIB level gradually increased with the increase of gestational weeks, and the difference was statistically significant (P＜0.05). The levels of FDP and D-dimer in the first trimester, second trimester and third trimester increased with the increase of gestational age, and the difference was statistically significant (P＜0.05). Conclusion: The detection of four coagulation levels, FDP and D-dimer levels before childbirth can master the coagulation function of patients and conduct timely preventive treatment of abnormal conditions, which is of great significance to the preventive treatment of bleeding and thrombosis in postpartum patients.