Reference intervals for D-dimer and fibrinogen in the Chinese population during the third trimester of pregnancy

Abstract

Aim: Pregnancy is a hypercoagulable state, however it remains unknown the degree to which pregnancy affects standardly drawn coagulation laboratory studies. We intended to establish reference intervals for D-dimer and fibrinogen in the third trimester of pregnancy. Methods: We recruited 1048 healthy Chinese pregnant women with low-risk pregnancy. Concentrations of D-dimer and fibrinogen in the third trimester were collected. The 2.5th and 97.5th percentile reference intervals of D-dimer and fibrinogen in pregnant women with parity = 1, parity≥2, maternal age<35 years, maternal age≥35 years, PPH and non-PPH were established during the third trimester of pregnancy. Results: D-dimer levels were above the conventional cut-off point (0.5 mg/L) in 99.33% of pregnant women. Fibrinogen levels were above the normal upper limit (4 g/L) in 63.93% of pregnant women. The reference interval of D-dimer and fibrinogen in the third trimester of low-risk pregnant women was 0.63-5.05 mg/L and 3.02-5.92 g/L, respectively. Conclusion: The concentration of Ddimer and fibrinogen in the blood during pregnancy differ from the normal population. We recommend that the reference intervals be established for Chinese healthy pregnant women.