Concentration of fibrin monomer in pregnancy and during the postpartum period

Abstract

Background D-dimer increases during pregnancy and is problematic to use in the diagnosis of venous thromboembolism. Fibrin monomer represents an alternative biomarker for venous thromboembolism. However, to be useful in pregnancy, the fibrin monomer concentration should be stable throughout pregnancy and during postpartum. Methods To describe the course of fibrin monomer concentration during pregnancy and the postpartum period in healthy pregnant women and to compare their within-subject biological variation (CVI) with non-pregnant women. Blood samples were obtained every fourth week during pregnancy and three samples after delivery in 20 healthy women and every fourth week during a 40-week period in 19 healthy non-pregnant women. Fibrin monomer (STA Liatest FM, Stago) was analysed in duplicates for all samples. Concentrations of fibrin monomer in pregnant and non-pregnant women were compared and the CVI for fibrin monomer was calculated. Results The median fibrin monomer concentration in pregnant women was 6.2 mg/L (2.5 and 97.5 percentiles 3.7–10.8 mg/L) and in non-pregnant women 4.8 mg/L (3.6–8.2) ( P < 0.01). The fibrin monomer concentration was relatively stable during pregnancy, although a few unexplained high fibrin monomer concentrations were found during pregnancy/postpartum. Fibrin monomer CVI in pregnancy and postpartum was 20.6% (95% CI 18.3, 23.5) and in non-pregnant 16.1% (13.7, 18.9). Conclusions For clinical purposes, fibrin monomer concentration can be considered stable during pregnancy, although it is slightly higher than in non-pregnant women. Pregnant and non-pregnant women have the same CVI. The suitability of fibrin monomer in venous thromboembolism diagnosis in pregnant women should be validated in further studies.

Establishing Expectancy Values for Fibrin Monomer in Uncomplicated Pregnancy

“… 35 In previous studies concerning FM levels, patients with pregnancy complications were excluded 17 18 20 21 22 or considered “healthy” if they had no personal or family history of VTE. 20 23 Interestingly, Grossmann et al excluded patients on anticoagulation 22 and Joly et al excluded those with any form of antithrombotic treatment. 20 None of these studies explicitly excluded patients with thrombophilia, and in a study by Kristoffersen et al, these patients were noted to be present.…”

“…20 None of these studies explicitly excluded patients with thrombophilia, and in a study by Kristoffersen et al, these patients were noted to be present. 23 Information about antithrombotic treatments and VTE risks was absent in a study by Kawamura et al 21 ; however, for FM (STA-R), they considered an FM level of !35 µg/mL to be as abnormal, which is in accordance with our result of an FM level of 37.9 µg/mL falling in the 97.5 th percentile. In their study, patients were excluded if they had not undergone all scheduled examinations.…”

“…17,18 To date, only a few studies have investigated FM in pregnancy via LIA, specifically the Auto LIA FM kit (Nissui Pharmaceutical Co Ltd, Tokyo, Japan) 17,19 and STA-LIATESTFM (Diagnostica Stago, Asnières sur Seine, France). [20][21][22][23] In a previous study, Grossman et al concluded that FM and DD are influenced by various maternal and obstetric factors and not solely gestational age, and that these parameters should therefore be considered when ruling out VTE in pregnancy. 22 The aim of our prospective study was to describe in detail hemostasis activation during pregnancy, evaluate the impact of maternal clinical characteristics such as thrombophilia and/or antithrombotic therapy on hemostasis, and establish reference values for FM, F1 þ 2, TAT, and DD in pregnant patients.…”

“… 17 18 To date, only a few studies have investigated FM in pregnancy via LIA, specifically the Auto LIA FM kit (Nissui Pharmaceutical Co Ltd, Tokyo, Japan) 17 19 and STA-LIATESTFM (Diagnostica Stago, Asnières sur Seine, France). 20 21 22 23 …”

Reference Value Fibrin Monomer in Healthy Children: A Cross-Sectional Study

“… 8 Measuring FM can also help evaluate hypercoagulation in pregnant women, predicting the risk of thrombosis. 9 …”