Changes in levels of coagulation parameters in different trimesters among Chinese pregnant women

Background This article is to explore changes in levels of coagulation parameters in different trimesters among healthy pregnant women in China. Methods A total of 760 eligible women were enrolled (first-trimester group: n = 183, second-trimester group: n = 183, third-trimester group: n = 263, non-pregnant group: n = 131). Seven parameters including prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (FIB), D-dimer (DD), fibrinogen degradation products (FDP), and antithrombin III (ATIII), of all participants were collected. The non-parametric 2.5th-97.5th percentiles reference intervals were calculated for each parameter. Results The reference intervals for FIB, PT, APTT, TT, FDP, DD, and ATIII at first trimester were 2.11-4.32 g/L, 10.90-13.85 s, 24.60-39.28 s, 12.95-15.88 s, 0.04-2.55 mu g/mL, 0.03-1.15 mu g/mL, and 75.57%-125.31%, respectively. The reference intervals at second trimester were 2.31-4.77 g/L, 9.70-12.64 s, 24.16-35.43 s, 12.95-15.88 s, 0.15-7.40 mu g/mL, 0.08-2.13 mu g/mL, and 74.35%-119.28%, respectively. For the third-trimester, the intervals were 2.39-4.96 g/L, 9.20-11.95 s, 23.90-35.51 s, 13.41-18.00 s, 0.55-13.43 mu g/mL, 0.15-3.60 mu g/mL, and 71.61%-118.29%, respectively. The third-trimester group showed decreased PT, APTT, and ATIII and increased FIB, TT, DD and FDP as compared with the other groups. Conclusion In this study, level changes of coagulation parameters in different trimesters were observed. And the ranges for coagulation parameters were presented, which may provide some reference for clinicians to more accurately monitor the coagulation and fibrinolytic system in pregnant women.