Low-molecular-weight heparin during pregnancy

Epidemiology and prevention of venous thromboembolism

Venous thromboembolism, that consists of the interrelated conditions deep-vein thrombosis and pulmonary embolism, is an under-appreciated vascular disease. In Western regions, approximately 1 in 12 individuals will be diagnosed with venous thromboembolism in their lifetime. Rates of venous thromboembolism are lower in Asia, but data from other regions are sparse. Numerous risk factors for venous thromboembolism have been identified, which can be classified as acute or subacute triggers (provoking factors that increase the risk of venous thromboembolism) and basal or acquired risk factors (which can be modifiable or static). Approximately 20% of individuals who have a venous thromboembolism event die within 1 year (although often from the provoking condition), and complications are common among survivors. Fortunately, opportunities exist for primordial prevention (prevention of the development of underlying risk factors), primary prevention (management of risk factors among individuals at high risk of the condition) and secondary prevention (prevention of recurrent events) of venous thromboembolism. In this Review, we describe the epidemiology of venous thromboembolism, including the incidence, risk factors, outcomes and opportunities for prevention. Meaningful health disparities exist in both the incidence and outcomes of venous thromboembolism. We also discuss these disparities as well as opportunities to reduce them.

Autoimmune disease and risk of postpartum venous thromboembolism

Background

The risk of pregnancy-related mortality in the United States has nearly doubled since 1990, with venous thromboembolism (VTE) accounting for approximately 10% of these deaths.

Objectives

The objective of this study was to assess whether preexisting autoimmune disease is a risk factor for postpartum VTE.

Methods

Using the MarketScan Commercial and Medicare Supplemental administrative databases, a retrospective cohort study analyzed whether postpartum persons with autoimmune disease had a higher risk of postpartum VTE incidence than postpartum persons without autoimmune disease. Using International Classification of Diseases codes, we identified 757,303 individuals of childbearing age who had a valid delivery date with at least 12 weeks of follow-up.

Results

Individuals were, on average, 30.7 years old (SD, 5.4), and 3.7% (N = 27,997 of 757,303) of them had evidence of preexisting autoimmune disease. In covariate-adjusted models, postpartum persons with preexisting autoimmune disease had higher rates of postpartum VTE than postpartum persons without autoimmune disease (hazard ratio [HR], 1.33; 95% CI, 1.07-1.64). When analyzed by individual autoimmune disease, those with systemic lupus erythematosus (HR, 2.49; 95% CI, 1.47-4.21) and Crohn's disease (HR, 2.49; 95% CI, 1.34-4.64) were at an elevated risk of postpartum VTE compared with those without autoimmune disease.

Conclusion

Autoimmune disease was associated with a higher rate of postpartum VTE, with evidence that the association was most pronounced among individuals with systemic lupus erythematosus and Crohn's disease. These findings suggest that postpartum persons of childbearing age with autoimmune disease may require more monitoring and prophylactic care after delivery to prevent potentially fatal VTE events.

The role of low molecular weight heparin on recurrent pregnancy loss: A systematic review and meta-analysis

To assess the roles of the low molecular weight heparin (LMWH) on recurrent pregnancy loss (RPL). The relevant studies of all randomized controlled trials (RCTs) were retrieved, and the systematic evaluation was conducted. PubMed, Embase, and Cochrane library databases were searched by using keywords, including low-molecular-weight heparin or LMWH, and recurrent miscarriage or recurrent pregnancy loss in pregnant women from their earliest data to February 2020. Two investigators independently evaluated eligibility. Risk ratios (RRs) and their corresponding 95% confidence interval (CI) were determined. To pool the results, this meta-analysis was performed using random-effect model due to the high heterogeneity among these eight studies. A total of eight RCTs involving 1854 participants were included in the meta-analysis involving 963 patients with RPL who were prescribed LMWH (enoxaparin, tinzaparin, or dalteparin) alone and 891 patients who were treated with no LMWH interventions (placebo, folic acid or non-treatment) were compared. Pooled data from the remaining eight RCTs showed the differences between intervention groups and control groups. Compared with control groups, LMWH had significantly improved live births (RR,1.19; 95%CI, 1.03 to 1.38; P = 0.02), and reduced miscarriage rates (RR, 0.62; 95%CI, 0.43 to 0.91; P = 0.01). The study suggested that LMWH could improve the live births and reduce the miscarriage rates of RPL. Therefore, LMWH might be a good treatment choice for women with unexplained PRL.

Low-Molecular-Weight Heparin for the Treatment of Unexplained Recurrent Miscarriage With Negative Antiphospholipid Antibodies: A Randomized Controlled Trial

BACKGROUND

Recurrent miscarriage (RM) is one of the most common clinical problems in reproduction with no definite cause in about 50% of the cases. The study aims to evaluate the effect of low-molecular-weight heparin (LMWH) in the treatment of women with RM negatively tested for antiphospholipid antibodies (APAs).

METHODS

An open-labeled registered randomized controlled study (NCT 01608347) included women who attended the outpatient clinic in Assiut Women Health Hospital and Nag-Hamady Central Hospital, Egypt, with 3 or more unexplained RM. Eligible participants were randomly assigned into 2 groups. The study group included 150 patients receiving LMWH (Tinzaparin sodium 4500 IU) subcutaneous daily injection with 500 µg folic acid once daily orally started once positive pregnancy test till the 20th week of gestation. The control group included 150 patients receiving the same dose of folic acid alone. The primary outcome of the study was the rate of continuation of a viable pregnancy after 20 weeks of gestation.

RESULTS

There was no significant difference between both groups as regards age, parity, or number of previous miscarriages. There was a significant increase in women who continued their pregnancy beyond 20 weeks in the study group compared to the control group (73.3% vs 48%, respectively; P = .002). The take-home baby rate was also significantly higher in the LMWH group compared to the control group ( P = .001).

CONCLUSION

Early start of LMWH decreases the incidence of miscarriage in the first 20 weeks of pregnancy in women with unexplained RM negative for APAs.

Pregnancy Loss, Polycystic Ovary Syndrome, Thrombophilia, Hypofibrinolysis, Enoxaparin, Metformin

Thrombophilia, hypofibrinolysis, and polycystic ovary syndrome (PCOS) are associated with recurrent pregnancy loss (RPL) and spontaneous abortion (SAB) alone and concurrently. The efficacy and safety of combined enoxaparin-metformin was prospectively assessed in women with PCOS with one or more previous SAB, thrombophilia, and/or hypofibrinolysis. Twenty-four white women with PCOS were studied; 23 with previous pregnancies, seven with RPL of unknown etiology (≥ three consecutive pregnancy losses <20 weeks’ gestation), two with two consecutive SABs, 13 with one SAB, and one with one live birth (HELLP syndrome). Prospectively, metformin (1.5 to 2.55 g/day) was administered before and throughout gestation, with concurrent enoxaparin (60 mg/day) throughout gestation. The 24 cases differed from 93 normal white female controls for the factor V Leiden mutation, 17% vs. 2%, Fisher’s p [pf] = .016, and for the 4G4G mutation of the plasminogen activator inhibitor-1 (PAI-1) gene (46% vs. 24%, Chi-square 4.63, p =. 031). The patients also differed from 44 normal white female controls for high levels (> 21.1 U/mL) of the PAI-1 gene product, plasminogen activator inhibitor activity (PAI-Fx) (33% vs. 8%, pf =. 018), and for high factor VIII (>150%) (22% vs. 0%, pf = .037). Of the 24 women, 23 had 65 previous pregnancies without metformin or enoxaparin, with 18 live births, 46 SAB (71%), and one elective abortion. On metforminenoxaparin, the same 23 women had 26 current pregnancies (28 fetuses), with 20 live births, two normal pregnancies 13 weeks or longer, and six SAB (21%), 3.4-fold lower than previous gestations (McNemar’s S = 33.6, p <. 0001). There were no adverse maternal or fetal therapy effects. Enoxaparin-metformin reduces pregnancy loss in women with PCOS with one or more previous SAB, who also have thrombophilia and/or hypofibrinolysis.

Bone status of children born from mothers with autoimmune diseases treated during pregnancy with prednisone and/or low molecular weight heparin

BACKGROUND

To evaluate bone status in children born from mothers followed for autoimmune diseases and treated during pregnancy with low molecular weight heparin (LMVH) and/or prednisone.

FINDINGS

History, physical examination, laboratory tests and phalangeal ultrasonography were performed. Demographic, clinical, and laboratory data were entered into a customized database, and results were analyzed with SPSS software. In children whose mothers were treated with LMWH, we retrieved dried blood spots taken for newborn screening, and analyzed the presence of heparin with tandem mass spectrometry. We enrolled 27 females and 14 males born from 31 mothers with SLE or connective tissue diseases. These women were continuously treated during pregnancy with LMWH (n = 10), prednisone (n = 16), or both (n = 15). Bone ultrasound revealed low values (≤ 3 centile for age) in ten patients. In a multistep regression analysis, age at examination resulted the single predictor of low ultrasound values (p < 0.004). Tandem mass spectroscopy failed to determine traces of heparin in newborn blood.

CONCLUSIONS

Children born from mothers with autoimmune diseases are at risk to develop reduced bone mass. The administration of LMWH and of prednisone seems to be safe with regard to children's bone health.

Postcesarean thromboprophylaxis with two different regimens of bemiparin

Objectives. To compare the effectiveness of postcesarean thromboprophylaxis with two different regimens of bemiparin. Material and Methods. The study included 646 women with cesarean delivery in our hospital within a 1-year period, randomly assigned to one of two groups for prophylaxis with 3500 IU bemiparin once daily for 5 days or 3500 IU bemiparin once daily for 10 days. Results. There was one case of pulmonary embolism (first day following cesarean). An additional risk factor was present in 98.52% of the women, most frequently emergency cesarean, anemia, or obesity. The only risk factors for thromboembolic disease significantly related to pulmonary thromboembolism were placental abruption and prematurity. There were no differences in thromboembolic events among the two thromboprophylaxis regimens. Conclusions. Cesarean-related thromboembolic events were reduced in our study population due to the thromboprophylactic measures taken. Thromboprophylaxis with 3500 IU bemiparin once daily for 5 days following cesarean was sufficient to avoid thromboembolic events.

Anti-phospholipid antibodies and other immunological causes of recurrent foetal loss--a review of literature of various therapeutic protocols

PROBLEM

An immune-based aetiology is one of the several accepted causes for recurrent foetal loss (RFL). However, most of the immunological theories have not fulfilled the criteria for causality. This is a review of the various immunological causes of RFL and the outcome of different treatment protocols.

METHOD OF STUDY

Both auto- and alloimmune maternal immunological abnormalities have been proposed to account for foetal loss. Among the autoimmune factors, anti-phospholipid antibodies (APAs) have been demonstrated to be the strongest risk factors for foetal loss, the prevalence of which is as high as 40% in women with RFL. Other autoimmune antibodies implicated in RFL are anti-nuclear antibodies (ANAs), anti-thyroid antibodies and anti-endothelial cell antibodies. The alloimmune factors implicated in pregnancy loss of unknown aetiology include abnormal natural killer (NK) cell activity, alteration in T helper 1 (Th1) and T helper 2 (Th2) ratios, presence of alloimmune antibodies like anti-paternal cytotoxic antibodies, anti-idiotypic antibodies, mixed lymphocyte reaction blocking antibodies and abnormal expression of HLA-G molecules. Management of patients with RFL is mainly based on immunomodulatory (prednisolone, intravenous immunoglobulins, plasma exchange, paternal lymphocyte therapy), anti-aggregation (aspirin) or anti-coagulation (unfractionated or low molecular weight heparin) agents.

RESULTS

Low-molecular-weight heparin with low-dose aspirin has been found to be the most effective treatment for women with APAs and RFL. Differences in dosage, timing of treatment, inclusion criteria, outcome assessment parameters etc. are some of the factors which have resulted in discrepancies in various reports.

CONCLUSION

Identification of the immunological mechanisms involved in pregnancy loss and the action of different therapeutic reagents is important so that effective therapies can be designed and investigated.

Enoxaparin-metformin and enoxaparin alone may safely reduce pregnancy loss

Polycystic ovary syndrome (PCOS), thrombophilia, and hypofibrinolysis are associated with recurrent pregnancy loss (RPL) and spontaneous abortion (SAB). In 28 Caucasian women, 21 women with PCOS (4 with previous thrombosis, 18 with 1 SAB or more, and 20 with 1 coagulation disorder or more), and 7 women with coagulation disorders-thrombi, we speculated that prospective treatment with enoxaparin-metformin or enoxaparin alone would successfully and safely promote healthy live births compared with previous untreated pregnancies. In 21 women with PCOS, metformin (1.5-2.55 g/day) was given before and during pregnancy with concurrent enoxaparin (60 mg/day). Of 21 PCOS women, 19 women had 40 previous untreated pregnancies, 7 had live births (18%), 3 had elective abortions (ABs) (8%), and 30 had SABs (75%). On enoxaparin-metformin, these 19 women had 24 pregnancies, 20 live births (83%), and 4 SABs (17%); the SAB rate was 4.4-fold lower than previous untreated pregnancies (McNemar's s = 20.8, P < 0. 0001). Two women with PCOS without previous pregnancies, but with previous thrombosis, had 2 pregnancies on enoxaparin-metformin and 2 live births. Of the 7 women with coagulation disorders-thrombi, 4 had 15 previous pregnancies without enoxaparin, with 6 live births (40%), 8 SABs (53%), and 1 elective AB (7%). On enoxaparin, these 4 women had 4 pregnancies, with 4 (100%) live births (McNemar's s = 8.0, P = 0.005). The other 3 women with coagulation disorders-thrombi had 4 pregnancies on enoxaparin with 4 live births. No adverse maternal-fetal side effects were reported on enoxaparin alone or enoxaparin-metformin. Enoxaparin-metformin reduces pregnancy loss in women with PCOS-coagulation disorders and in women with coagulation disorders-thrombi.

Antithrombotic therapy and pregnancy: consensus report and recommendations for prevention and treatment of venous thromboembolism and adverse pregnancy outcomes

Venous thromboembolism and adverse pregnancy outcomes are potential complications of pregnancy. Numerous studies have evaluated both the risk factors for and the prevention and management of these outcomes in pregnant patients. This consensus group was convened to provide concise recommendations, based on the currently available literature, regarding the use of antithrombotic therapy in pregnant patients at risk for venous thromboembolic events and adverse pregnancy outcomes.

Management of Thrombosis in Antiphospholipid Syndrome and Systemic Lupus Erythematosus in Pregnancy

Pregnancy is a high risk period for thrombosis in women with antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE) with antiphospholipid antibodies (aPL). Thrombosis may affect the mother, both in the venous and arterial beds, and also have a role in pregnancy loss. Thromboprophylaxis thus is warranted in most of these women. However, specific regimens containing low-dose aspirin, unfractionated heparin (UH), low molecular weight heparin (LMWH), and even dicumarinics in some circumstances after the first trimester are still a matter of controversy. Women with previous thrombosis should receive full antithrombotic doses of UH or LMWH during the whole pregnancy. Treatment of pregnancy losses is more debated, consisting of low-dose aspirin with or without associated heparin. The choice of treatment for a given patient must always take into account the woman's opinion after a careful discussion with the treating physician. Peripartum thromboprophylaxis with LMWH in women receiving aspirin-only regimens and prevention of osteoporosis in those treated with heparin are considered essential in the medical management of these patients.

Stroke in pregnancy

Stroke in pregnancy and the puerperium is a rare but serious cause of maternal and fetal mortality. Pregnancy-associated maternal changes should remain additional considerations in the evaluation and treatment of the pregnant patient who has stroke and not preclude a comprehensive stroke evaluation. Instead, the approach to the pregnant patient who has stroke should include the evaluation of general causes of stroke in the young, with the additional consideration of the rare pregnancy-specific causes. Understanding the potential maternal and fetal risks of diagnostic testing and treatment is crucial to appropriate decision making when caring for the pregnant patient who has stroke.

Polycystic ovary syndrome, the G1691A factor V Leiden mutation, and plasminogen activator inhibitor activity: associations with recurrent pregnancy loss

Our specific aim was to assess associations of thrombophilia, hypofibrinolysis, and polycystic ovary syndrome (PCOS) with recurrent pregnancy loss (RPL) (>/=3 consecutive pregnancy losses < 20 weeks gestation). Prospective studies were performed in 33 Caucasian women referred for diagnosis and treatment of PCOS who were subsequently found to have RPL and in 16 Caucasian women referred for diagnosis and treatment of RPL, who did not have PCOS. Cases (PCOS-RPL, RPL without PCOS) were compared with controls (116 healthy Caucasian females) for the G1691A Factor V Leiden, G20210A prothrombin, C677T methylenetetrahydrofolate reductase (MTHFR), plasminogen activator inhibitor 4G/5G, and platelet glycoprotein PL A1A2 gene mutations. Cases were compared with controls (44 healthy adult Caucasian females) for serologic coagulation tests including homocysteine, proteins C, S, free S, antithrombin III, anticardiolipin antibodies IgG and IgM, dilute Russel's viper venom time, activated partial thromboplastin time, Factor VIII, Factor XI, lipoprotein (Lp)(a), and plasminogen activator inhibitor activity (PAI-Fx). The 33 Caucasian women with PCOS subsequently found to have RPL were 10% of a cohort of 322 Caucasian women who had >/= 1 previous pregnancy and had been referred for diagnosis and therapy of PCOS over a 4.3-year period. The Factor V Leiden G1691 mutation was present in 6 of 33 women (18%) with PCOS-RPL and in 3 of 16 women with RPL without PCOS (19%) versus 2 of 116 (1.7%) female controls, Fisher's P (p(f)) =.0016, p(f) =.013. The 33 PCOS-RPL cases also differed from the 44 female controls for high PAI-Fx (>21.1 U/mL), 38% versus 8%, p(f) =. 004. The thrombophilic G1691A Factor V Leiden mutation is associated with RPL in women with and without PCOS; hypofibrinolysis (high PAI-Fx) is also associated with RPL in women with PCOS.

Thrombocytopenia, low molecular weight heparin, and obstetric anesthesia

The parturient with coagulation defects, whether related to thrombocytopenia or to anticoagulation therapy, presents a unique challenge to the anesthesiologist. The risk of spinal or epidural hematoma in these patients has not been quantified fully but is a factor that one must consider on a case-by-case basis in determining whether neuraxial anesthesia is appropriate for the parturient. Following the guidelines set forth in this article should help reduce the risk of spinal or epidural hematoma without sacrificing the quality of care provided to patients.

Randomized study of subcutaneous low molecular weight heparin plus aspirin versus intravenous immunoglobulin in the treatment of recurrent fetal loss associated with antiphospholipid antibodies

OBJECTIVE

To compare the 2 most efficacious therapeutic regimens, intravenous immunoglobulin (IVIG) and anticoagulation with low molecular weight (LMW) heparin plus low-dose aspirin, in women with recurrent pregnancy loss associated with antiphospholipid antibodies (aPL).

METHODS

We examined 40 women with recurrent abortion (at least 3 occurrences) and repeatedly positive test results for anticardiolipin or lupus anticoagulant. The subjects were randomly assigned to treatment with IVIG or LMW heparin plus low-dose aspirin. Both therapies were started when the women were pregnant as documented by a positive urine test. IVIG was stopped at the thirty-first week of gestation, aspirin at the thirty-fourth week, and heparin at the thirty-seventh week. The primary outcome of interest was the rate of live births with the 2 treatments.

RESULTS

The characteristics of the 2 groups were similar at the time of randomization. The women treated with LMW heparin plus low-dose aspirin had a higher rate of live births (84%) than those treated with IVIG (57%).

CONCLUSION

Treatment with LMW heparin plus low-dose aspirin should be considered as the standard therapy for recurrent pregnancy loss due to aPL.

Safety of low molecular weight heparins in the treatment of venous thromboembolism

Low molecular weight heparins (LMWHs) are commonly employed as a substitute for unfractionated heparin (UFH) in the treatment of venous thromboembolic events. Despite their higher cost, the preferential use of LMWHs seemed justified initially as, based on the results of earlier meta-analyses, these compounds were deemed to be more effective and safer than UFH. Although, in this respect, their purported superiority over UFH could not be confirmed by subsequent large, randomised trials and updated meta-analyses, other peculiar features of LMWHs were highlighted, favouring their preferential utilisation in patients with venous thromboembolism. Among these, the possibility of once-daily administration on an out-patient basis, the lower incidence of Type II heparin-induced thrombocytopenia and the lower likelihood of osteoporosis after prolonged treatment periods, appear to be especially prominent. This review attempts to evaluate the available evidence focusing on the safety of LMWHs for the treatment of venous thromboembolism and the current therapeutic options and potential advantages of LMWHs, either in general or in selected patient populations.

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.

Severe obstetric morbidity

Obstetric morbidity is an important marker of the quality of obstetric care. This review explores the definition, incidence and significance of obstetric morbidity. Some topical issues related to obstetric morbidity are discussed. In addition, the importance of long-term morbidity and violence against women is highlighted.