Congenital thrombophilia associated to obstetric complications

Changes in coagulation and hemodynamics during pregnancy: a prospective longitudinal study of 58 cases

PURPOSE

To investigate changes and establish reference values in coagulation, anticoagulation, fibrinolysis, anti-fibrinolysis and hemodynamics during normal pregnancy.

METHODS

A total of 58 women with singleton pregnancies were recruited. Blood and ultrasound examinations were performed in the 10th-14th, 20th-24th, and 30th-34th weeks of pregnancy. The same examinations were performed in 50 non-pregnant women who were selected as the control group.

RESULTS

Levels of fibrinogen, thrombin time, fibronectin, prothrombin activated fragments 1+2 and thrombomodulin were higher in early pregnancy than those in the control group (P < 0.05). Fibrinogen, prothrombin time, activated partial thromboplastin time, thrombin time, thromboxane B2, prothrombin activated fragments 1+2, thrombomodulin, D-dimer, and plasminogen activator inhibitor-2 were statistically different between the mid pregnancy and the control group (P < 0.05). Meanwhile, fibrinogen, prothrombin time, activated partial thromboplastin time, thrombin time, fibronectin, thromboxane B2, prothrombin activated fragments 1+2, thrombomodulin, and plasminogen activator inhibitor-2 were obviously elevated in late pregnancy as compared with the control group (P < 0.05). Moreover, fibrinogen, thromboxane B2, prothrombin activated fragment 1+2, D-dimer plasminogen, and activator inhibitor-2 gradually increased during pregnancy with some fluctuation. Prothrombin time, activated partial thromboplastin time, thrombin time, international normalized ratio, and thrombomodulin as well as systolic/diastolic ratio, pulsatility index, and resistance index in uterine arteries showed a tendency to decrease in pregnant women.

CONCLUSIONS

Coagulation, anti-coagulation, fibrinolytic and anti-fibrinolytic activities are enhanced and balanced at a higher level during pregnancy. In addition, uterine artery and umbilical artery hemodynamics become more baby friendly (i.e., high flow and low resistance).

Inherited Thrombophilia

Inherited thrombophilia can be defined as a genetically determined predisposition to the development of thromboembolic complications. Since the discovery of activated protein C resistance in 1993, several additional disorders have been described and, at present, it is possible to identify an inherited predisposition in about 60 to 70% of patients with such complications. These inherited prothrombotic risk factors include qualitative or quantitative defects of coagulation factor inhibitors, increased levels or function of coagulation factors, defects of the fibrinolytic system, altered platelet function, and hyperhomocysteinemia. In this review, the main inherited prothrombotic risk factors are analyzed from epidemiological, laboratory, clinical, and therapeutic points of view. Finally, we discuss the synergism between genetic and acquired prothrombotic risk factors in particular conditions such as childhood and pregnancy.

Placental dermatan sulfate: isolation, anticoagulant activity, and association with heparin cofactor II

Pregnancy is associated with hemostatic challenges that may lead to thrombosis. Heparin cofactor II (HCII) is a glycosaminoglycan-dependent thrombin inhibitor present in both maternal and fetal plasma. HCII activity increases during pregnancy, and HCII levels are significantly decreased in women with severe pre-eclampsia. Dermatan sulfate (DS) specifically activates HCII and is abundant in the placenta, but the locations of DS and HCII in the placenta have not been determined. We present evidence that DS is the major anticoagulant glycosaminoglycan in the human placenta at term. DS isolated from human placenta contains disaccharides implicated in activation of HCII and has anticoagulant activity similar to that of mucosal DS. Immunohistochemical studies revealed that DS is associated with fetal blood vessels and stromal regions of placental villi but is notably absent from the syncytiotrophoblast cells in contact with the maternal circulation. HCII colocalizes with DS in the walls of fetal blood vessels and is also present in syncytiotrophoblast cells. Our data suggest that DS is in a position to activate HCII in the fetal blood vessels or in the stroma of placental villi after injury to the syncytiotrophoblast layer and thereby inhibit fibrin generation in the placenta.

Genetic prothrombotic risk factors in women with unexplained pregnancy loss

INTRODUCTION

Inherited thrombophilia has been associated with unexplained recurrent pregnancy loss (RPL) and stillbirth. This thrombotic tendency can manifest as thrombotic lesions in the placenta, and may lead to abortion and stillbirth. The aim of our case-control study was to investigate the prevalence of FVL and FII G20210A in women with adverse pregnancy outcome, compared to the prevalence of the same mutations in our health control group.

MATERIALS AND METHODS

102 consecutive women with unexplained pregnancy loss (55 with history of RPL, and 47 with history of stillbirth) were studied for hereditary thrombophilia. The health control group consisted of 217 healthy women from the general population.

RESULTS AND CONCLUSIONS

Of the 55 women with recurrent abortions, we found the same prevalence for the FVL and the FII G20210A(9.1%, 5 pts). (p=NS compared to control group). Of the 47 women with stillbirth, 11 (23.4%) had the FVL and 9 (19.1%) had the FII G20210A(p<0.0005 for both mutations). In our experience the prevalence of FVL and the FII G20210Amutations was significantly higher in women with unexplained stillbirth, instead the prevalence of genetic thrombophilia was high but not statistically significant in women with recurrent pregnancy loss.

Factor II

OBJECTIVE

To evaluate whether the determination of maternal plasma Factor II:C (FII:C) and mean uterine artery resistance index may be useful to early predict pre-eclampsia in patients with gestational hypertension.

DESIGN

Prospective study.

SETTING

Consecutive enrollment in a public tertiary clinical care centre.

PATIENTS

A total of 65 women with gestational hypertension at 24-26 weeks.

INTERVENTION

Measurements of maternal plasma FII:C activity levels, ultrasonographic biometrical parameters and Doppler velocimetry of maternal uterine arteries.

MAIN OUTCOME MEASURE(S)

The probability of developing pre-eclampsia was the main outcome of the study and it was computed by combining the FII:C and the mean uterine artery resistance index cut-off points, chosen by receiver operating characteristic (ROC) curve analysis.

RESULTS

F-II:C activity levels and mean uterine artery resistance index were significantly (both P < 0.01) higher in women who developed pre-eclampsia. A weak, but significant correlation (r = 0.3, P < 0.05) was found between these two parameters. FII:C activity levels at the cut-off value of 136.5% achieved a sensitivity of 61.1% and a specificity of 71.3%, while mean uterine artery resistance index (RI) at the cut-off value of 0.57 showed a sensitivity of 85.7% and a specificity of 90.2% in predicting the onset of pre-eclampsia. When both FII:C and mean uterine RI were over the cut-off points the positive predictive value was of 89%, with a 100% negative predictive value when both were below the cut-off points.

CONCLUSION

F-II:C activity levels and mean uterine artery resistance index determination at mid trimester may improve the prediction of superimposed pre-eclampsia on women with early onset gestational hypertension.

Preeclampsia and its interaction with common variants in thrombophilia genes

Recently, it has been proposed that abnormalities in coagulation and fibrinolysis contribute to the development of preeclampsia by increasing the thrombotic tendency. This hypothesis was tested in women who have had preeclampsia (cases) compared with matched controls. Polymorphisms in the thrombophilia genes [plasminogen activator inhibitor type 1 [PAI-1 -675(4G/5G)], thrombin activatable fibrinolysis inhibitor (TAFI -438G/A and 1040C/T), methylenetetrahydrofolate reductase (MTHFR 677C/T), factor V (FV Leiden R/Q506), prothrombin (FII 20210G/A) and factor XIIIA (FXIIIA V/L34)] were determined in 157 women with preeclampsia and 157 women with uncomplicated pregnancy. The associated risk of preeclampsia was analyzed using logistic regression methods. The frequency distributions of the genotypes of these six polymorphisms in thrombophilia genes were similar in the case and control groups. We found no differences in the prevalence of genetic risk factors of thrombosis in women with preeclampsia compared with controls, which makes it unlikely that these polymorphisms are risk factors for preeclampsia.