Thrombophilia and pregnancy: review of the literature and some original data

How can Secondary Thromboprophylaxis in High-Risk Pregnant Patients be Improved?

Low-molecular-weight heparin (LMWH) is suggested for thromboprophylaxis in pregnant women with previous venous thromboembolism (VTE). Anyway, there is only limited amount of studies evaluating the effect of LMWH on hemostatic parameters during pregnancy of patients with previous VTE and the need of secondary thromboprophylaxis. We therefore provide results of prospective and longitudinal assessment of changes in hemostasis in high-risk pregnant women at four times during pregnancy (T1–T4) and one time after the postpartum period (T5) used for individualized modification of thromboprophylaxis. In this study, the results of coagulation factor VIII (FVIII) and protein S (PS) activity, ProC Global ratio and anti-Xa activity were evaluated. Despite the thromboprophylaxis, an increased predisposition to thromboembolic complications was detected (significant increase in FVIII activity and decrease in PS function, ProC Global ratio not normalized even after the postpartum period – p < .0001 between controls and T5 for PS and ProC Global). These results indicate that hemostasis may not be restored even 6 to 8 weeks after delivery and pose the question when is it safe to withdraw the anticoagulant thromboprophylaxis in high-risk patients with prior VTE.

Perinatal arterial ischemic stroke

Perinatal arterial ischemic stroke is a relatively common and serious neurologic disorder that can affect the fetus, the preterm, and the term-born infant. It carries significant long-term disabilities. Herein we describe the current understanding of its etiology, pathophysiology and classification, different presentations, and optimal early management. We discuss the role of different brain imaging modalities in defining the extent of lesions and the impact this has on the prediction of outcomes. In recent years there has been progress in treatments, making early diagnosis and the understanding of likely morbidities imperative. An overview is given of the range of possible outcomes and optimal approaches to follow-up and support for the child and their family in the light of present knowledge.

Review of Management and Outcomes in Women with Thrombophilia Risk during Pregnancy at a Single Institution

Pregnancy is a hypercoagulable state associated with an increased risk of venous thromboembolic disease (VTE). We retrospectively studied 38 Caucasian pregnant women with thrombophilia risk and compared their obstetric outcomes with a matched cohort without known thrombophilia risk during the period between January 2007 and December 2010. There were (2) cases with factor V Leiden, (6) prothrombin gene mutation, (1) antithrombin III deficiency, (2) protein C deficiency, (3) protein S deficiency, (10) MTHFR mutation, (7) anti-cardiolipin antibodies, and (1) lupus anticoagulant. Patients without thrombophilia who presented with recurrent unprovoked VTE were considered as high risk (6 cases). Most patients received anticoagulation (34/38) with aspirin only (6), enoxaparin (27), and warfarin (1). Twenty-six out of thirty-eight pregnant women (68.4%) with an increased risk of thrombophilia experienced one or more obstetric complications defined as hypertension, preeclampsia, placenta abruptio, VTE, and oligohydramnios, compared with 15 out of 40 (37.5%) pregnant women in the control group (OR 3.6; 95% CI 1.42, 9.21, P < 0.001). The incidence of obstetric complications was significantly higher in the thrombophilia group compared to the controls. However, these complications were the lowest among patients who received full-dose anticoagulation. Our study suggests that strict application of anticoagulation therapy for thrombophilia of pregnancy is associated with an improved pregnancy outcome. The study was registered in the Australian and New Zealand Clinical Trials Registry under ACTRN12612001094864.

Clinical characteristics and type of thrombophilia in women with pregnancy-related venous thromboembolic disease

BACKGROUND

Normal pregnancy is characterized by numerous changes in the hemostatic system, creating the hypercoagulable state which increases the risk of venous thromboembolic event (VTE) occurrence. The risk is further increased by the presence of inherited or acquired thrombophilia.

OBJECTIVE

In this study, we aimed to determine the prevalence of different types of thrombophilia in women with pregnancy-related VTE, and to investigate the possible connection between the type of thrombophilia and localization of VTE as well as the gestational age of VTE occurrence.

PARTICIPANTS AND METHODS

Two hundred and two women with the first episode of pregnancy-related VTE and 130 controls were investigated. The antithrombin, protein C and protein S activity, APC resistance, FVG1691A, and FIIG20210A were determined. None of the investigated women was pregnant at the time of thrombophilia testing, and none was using oral contraceptives.

RESULTS

Thrombophilia was diagnosed in 95 patients (47%) and 7 controls (5.4%). The prevalence of FV Leiden, FIIG20210A mutations, antithrombin, PC and PS deficiencies taken together and combined thrombophilia was 22.3, 10.4, 6.9 and 6.9%, respectively. Significantly more frequent antepartum occurrence of VTE (11 vs. 3, p < 0.05) was found in women with natural coagulation inhibitor deficiency. Pulmonary embolism occurred more frequently in nonthrombophilic women (25 vs. 3, p < 0.001).

CONCLUSION

Inherited thrombophilia was found to be considerably more frequently present in women with pregnancy- and puerperium-related VTE compared to healthy controls. Women with thrombophilia are at higher risk of developing thromboses localized in the iliacofemoral region, and women without thrombophilia are at higher risk of developing pulmonary embolism. Deficiency in natural coagulation inhibitors is associated with antepartum VTE occurrence.

Preeclampsia and eclampsia incidence in the eastern anatolia region of Turkey: the effects of high altitude

OBJECTIVE

Hypertensive disorders of pregnancy remain a leading cause of maternal and perinatal mortality and morbidity. The purpose of this study was to determine the distribution map related to pregnancy toxicosis of provinces in our region and the effects of altitude on hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome and eclampsia.

MATERIALS AND METHODS

Patients who were admitted to Atatürk University, Obstetrics and Gynecology Department with preeclampsia, eclampsia and a diagnosis of HELLP syndrome for the 5 years between1998-2002 were chosen. The birth rate was obtained from the health directorate of provinces in our area during the same period. Provinces were divided into two groups by altitude: less than and more than 1500 m above sea level.

RESULTS

The rates of HELLP syndrome and eclampsia diagnoses were 1.4 per 10.000 patients living above 1500 m altitude. However, this rate was 0.96 per 10.000 patients living below 1500 m altitude (p < 0.01). The highest rate of eclampsia and HELLP syndrome was seen in the Ardahan province, in 36 patients per 10,000 births, whereas the lowest rate was seen in the Iğdır province, 9.9 patients per 10,000 births.

CONCLUSION

Altitude contributes to occurrence of HELLP syndrome and eclampsia. Since the rate of pregnancy related hypertension is higher at high altitude, it is vital that these patients should be diagnosed during the early stages of the diseases in order to decrease complications.

Still births--eight years experience at Aga Khan University Hospital Karachi, Pakistan

OBJECTIVES

To examine the possible etiological causes of still births during 8 years of clinical experience at a tertiary referral center, The Aga Khan University Hospital Karachi Pakistan. In addition, to compare demographic and medical risk factors along with analysis of cause of fetal death in different groups.

MATERIAL AND METHODS

This was a retrospective cohort study, conducted at the Aga Khan University Karachi, Pakistan over a period of 8-year period between January 2000 and January 2008. We reviewed 287 medical records of all women who had intrauterine fetal demise during study time period.

RESULTS

The prevalence of still births at our institution was 6.6 +/- 2.1 per 1000 total births. Congenital anomalies, maternal hypertension, and fetal growth restrictions were the three main causes of still births. About half of still births were among unbooked pregnant women. More than 90% of occurred during the ante natal period while 10% were intrapartum. Majority of stillborns were in macerated state when delivered.

CONCLUSION

Most of still births were due to known causes such as hypertension, congenital anomalies, and fetal growth restriction. Improvement in the management of hypertension and diagnosis of congenital anomalies is necessary. Results of the analysis urge on the need for antenatal care and compliance for follow-ups.

Deficiency of the natural anticoagulant proteins in women with pregnancy related venous thromboembolism

Inherited thrombophilia can be defined as a predisposition to thrombosis caused by heritable defects, such as mutations in genes encoding the natural anticoagulants or clotting factors. Pregnancy related risk of VTE is sixfold increased comparing to non pregnant age matched women. Pregnancy is an independent risk factor for the development of venous thromboembolism and this risk is further increased by the presence of thrombophilia. Aim of the study: The aim of the study was to evaluate the association between deficiency of natural anticoagulants: antithrombin, protein C and protein S and pregnancy related thromboembolism. We have determined the activities of antithrombin, proten C and protein S in 74 women with pregnancy related thrombosis and in 45 healthy women who had at least two uncomplicated pregnancies. Among the women with the history of venous thromboembolism antithrombin deficiency was found in 4 (5.4%), protein C deficiency in 2 (2.7%) and protein S deficiency in 5 (6.76%). The total of 11 (14.6%) women was found to be deficient. Not a single woman in the control group was found to be deficient in natural anticoagulants. Deficiencies of coagulation inhibitors are associated with an increased risk of venous thrombosis during pregnancy and puerperium (p= 0.006). Antithrombin, protein C and protein S deficient women are at higher risk of developing venous thromboembolism during antepartal period (p= 0.0097). Prophylactic treatment with heparin should be recommended from the very beginning of the following pregnancy in women with antithrombin, protein C or protein S deficiency.

Haemostatic changes and acquired activated protein C resistance in normal pregnancy

Influence of changes in levels of coagulation factors and anticoagulants on acquired activated protein C (APC) resistance were studied in 40 healthy women during normal pregnancy. Factor VIII (FVIII), von Willebrand factor antigen (VWF:Ag), free protein S (FPS) and protein C were determined at 5-13, 14-26 and 27-40 weeks gestation and more than 6 weeks postpartum. APC anticoagulant activity was determined by measuring the activated partial thromboplastin time before and after adding human APC, expressed as the APC-sensitivity ratio (APC-SR). During the second and third gestation trimesters a significant increase (P < 0.05) in FVIII and VWF:Ag levels and a decrease in FPS levels were seen compared with the first trimester. Postpartum FVIII and VWF:Ag levels significantly decreased and FPS levels increased compared with the third trimester. Protein C levels remained unchanged during pregnancy and postpartum. Between increased FVIII and lowered APC-SR a trend of inverse correlation (r = -0.329; P = 0.076) occurred in the second trimester. No correlation was found between APC-SR and FPS or VWF:Ag levels. A remarkable finding is the strong inverse relationship between APC-SR and protein C levels (r <or= -0.392; P < 0.05) during pregnancy and postpartum. This may indicate that anticoagulant activity of added human APC measured by activated partial thromboplastin time is diminished in the presence of high endogenous protein C levels. A possible hypothesis is steric hindrance by sample protein C of APC binding sites on target activated factor V and/or cofactor protein S. The clinical significance of this finding should be determined because it complicates the interpretation of lowered APC-SR.

Thromboembolic disease in pregnancy

Venous thromboembolic disease is a major cause of maternal morbidity and mortality. Virchow's triad of hypercoagulability, venous stasis, and vascular damage all occur during pregnancy. The risk of venous thromboembolism is five to six times higher during pregnancy and the puerperium. Risk factors include age greater than 35, antiphospholipid antibodies, inherited thrombophilias, operative delivery, increased parity, obesity, mechanical heart valves,and family history. Prophylactic and therapeutic anticoagulation is recommended for women at risk. Low molecular weight heparins are safe and effective in most cases.

Antiphospholipid syndrome

Antiphospholipid syndrome has received considerable attention from the medical community because of its association with a number of serious clinical disorders, including arterial and venous thromboembolism, acute ischemic encephalopathy, recurrent pregnancy loss, thrombocytopenia, and livido reticularis. It can occur within the context of several diseases, mainly autoimmune disorders, and is then called secondary antiphospholipid syndrome. However, it may be also be present without any recognizable disease, or so-called primary antiphospholipid syndrome. There is no defined racial predominance for primary antiphospholipid syndrome, although a higher prevalence of systemic lupus erythematosus (SLE) occurs in African Americans and the Hispanic population. Multiple terms exist for this syndrome, some of which can be confusing. Lupus anticoagulant syndrome, for example, is a misleading term, because patients may not necessarily have SLE, and it is associated with thrombotic rather than hemorrhagic complications. To avoid further confusion, antiphospholipid syndrome is currently the preferred term for this clinical syndrome. Antiphospholipid antibodies are found in 1% to 5% of young healthy control subjects; however, the incidence increases with age and coexistent chronic disease. The syndrome occurs most commonly in young to middle-aged adults; however, it also can occur in children and the elderly. Among patients with SLE, the prevalence of antiphospholipid antibodies is high, ranging from 12% to 30% for anticardiolipin antibodies, and 15% to 34% for lupus anticoagulant antibodies. In general, anticardiolipin antibodies occur approximately five times more often then lupus anticoagulant in patients with antiphospholipid syndrome. This syndrome is the most common cause of acquired thrombophilia, associated with either venous or arterial thrombosis or both. It is characterized by the presence of antiphospholipid antibodies, recurrent arterial and venous thrombosis, and spontaneous abortion. Rarely, patients with antiphospholipid syndrome may have fulminate multiple organ failure, or catastrophic antiphospholipid syndrome. This is caused by widespread microthrombi in multiple vascular beds, and can be devastating. Patients with catastrophic antiphospholipid syndrome may have massive venous thromboembolism, along with respiratory failure, stroke, abnormal liver enzyme concentrations, renal impairment, adrenal insufficiency, and areas of cutaneous infarction. According to the international consensus statement, at least one clinical criterion (vascular thrombosis, pregnancy complications) and one laboratory criterion (lupus anticoagulant, antipcardiolipin antibodies) should be present for a diagnosis of antiphospholipid syndrome. The hallmark result from laboratory tests that defines antiphospholipid syndrome is the presence of antibodies or abnormalities in phospholipid-dependent tests of coagulation, such as dilute Russell viper venom time. There is no consensus for treatment among physicians. Overall, there is general agreement that patients with recurrent thrombotic episodes require life-long anticoagulation therapy and that those with recurrent spontaneous abortion require anticoagulation therapy and low- dose aspirin therapy during most of gestation. Prophylactic anticoagulation therapy is not justified in patients with high titer anticardiolipin antibodies with no history of thrombosis. However, if a history of recurrent deep vein thrombosis or pulmonary embolism is established, long-term anticoagulant therapy with international normalized ratio (INR) of approximately 3 is needed.

Embryogenesis and gene targeting of coagulation factors in mice

Genetic or acquired thrombophilia of the pregnant mother has been associated with the occurrence of gestational vascular disease and recurrent fetal loss and may contribute to the aetiology of pre-eclampsia. This chapter reviews insights into this link between thrombophilia and pregnancy complications that were gained from the study of genetically altered mice. These studies strongly support the notion of a cause-effect relationship between altered function of the thrombomodulin-protein C pathway and adverse pregnancy outcome. Analysis of the mouse models highlights unique aspects of vascular structure and function at the feto-maternal interface, and exposes new biological functions of natural anticoagulant pathways in pregnancy. These roles are unrelated to the maintenance of vascular patency and may be mediated through specific signalling pathways activated by coagulation factors. Abnormal signalling by placental trophoblasts at the feto-maternal interface is suggested as a hitherto unrecognized mechanism that may underlie adverse pregnancy outcome associated with haemostatic disorders.

Use of the low-molecular-weight heparin nadroparin during pregnancy. A review

Antithrombotic therapy is often used during pregnancy for the treatment and prevention of venous thromboembolism, the prevention of systemic embolism in patients with heart valve prostheses and the prevention of foetal loss in patients with antiphospholipid syndrome. Low-molecular-weight heparins (LMWHs), including nadroparin, have largely replaced unfractionated heparin as the anticoagulant of choice. The use of the LMWH nadroparin in pregnant women at an increased risk of thromboembolism or foetal loss is discussed in this review. Deep vein thrombosis can be effectively treated or prevented with nadroparin without any serious adverse events. Nadroparin 0.1 ml/10 kg s.c. once daily prevents thromboembolic complications in pregnant women with heart valve prostheses. Nadroparin is also effective in preventing foetal loss, through contributing to normal placental development and in decreasing the risk of premature delivery in pregnant women with antiphospholipid syndrome or women with herpes and antiphospholipid syndrome. These results demonstrate nadroparin is effective, easy to administer and associated with a low incidence of foetal and maternal complications. The use of nadroparin at a prophylactic dose of 0.3 ml (2850 IU AXa, 95 IU/kg) (for high-risk patients, 0.3-0.6 ml) s.c. once daily, and a therapeutic dose of 0.1 ml/10 kg (95 IU/kg) s.c. twice daily, is in line with the latest international guidelines of the American College of Chest Physicans.

Antiphospholipid syndrome accompanying systemic lupus erythematosus

The aim of the study was the assessment of the prevalence of antiphospholipid syndrome (APS) in patients with systemic lupus erythematosus (SLE). 72 patients with SLE had been investigated, 66 females and six males, aged 17 to 70 years, average 37.03. The presence of APA was determined using both ELISA assay for antiphospholipid antibodies, ASSERACHROM APA by Diagnostica Stago and clotting tests for lupus anticoagulant: activated partial thromboplastin time (aPTT), tissue thromboplastin inhibition test (TTI) and dilute Russell viper venom time (dRVVT). Antiphospholipid antibodies have been found in 24 patients (33.44%), 10 of them were with positive lupus anticoagulant tests, 6 of them were with positive ELISA test, while 8 of them had positive coagulation and immunological tests. Clinical manifestations that could be related to antiphospholipid syndrome were present in 22 patients (30.5%). The most common were thrombotic complications in 16 patients (22.25), recurrent spontaneous abortions in 7 patients (9.7%) and thrombocytopenia in 1 patient (1.39%). Presence of antiphospholipid syndrome was determined in 15 patients (20.83%). We can conclude that there is a significant correlation between presence of antiphospholipid antibodies and both thrombotic events and recurrent spontaneous abortions in SLE patients. Occurrence of thrombotic complications is in direct correlation with the level of antiphospholipid antibodies.