Venous thromboembolism in pregnancy

Venous thromboembolism remains a common cause of direct maternal deaths in high-income settings such as the United Kingdom. Pregnancy alone increases the risk of deep vein thrombosis and pulmonary embolus at least five-fold, and many women develop or have additional risk factors for venous thrombosis during pregnancy and the puerperium, the latter representing the period of highest risk. Early and repeated risk stratification and adequate thromboprophylaxis, usually with low molecular weight heparin, is the key to preventing venous thromboembolism (VTE). Women with a past history of VTE, and those affected by thrombophilia, require multidisciplinary care involving an obstetric haematologist. Women suspected of having acute thromboembolism should be commenced on empirical treatment promptly prior to diagnostic confirmation. Pulmonary embolism should be considered as a differential diagnosis in maternal collapse.     

Risk factors for deep vein thrombosis and pulmonary embolism during pregnancy or post partum: a population-based, case-control study

OBJECTIVE: We sought to determine risk factors for deep vein thrombosis and pulmonary embolism during pregnancy or post partum. STUDY DESIGN: We performed a population-based case-control study. All Olmsted County, Minnesota, residents with a first lifetime deep vein thrombosis or pulmonary embolism during pregnancy or post partum from 1966 to 1990 were identified (N = 90). Where possible, a resident without deep vein thrombosis or pulmonary embolism was matched to each patient by date of the first live birth after the patient's child. The medical records of all remaining patients and all control subjects were reviewed for >25 baseline characteristics, which were tested as risk factors for deep vein thrombosis or pulmonary embolism. RESULTS: In multivariate analysis smoking (odds ratio, 2.4) and prior superficial vein thrombosis (odds ratio, 9.4) were independent risk factors for deep vein thrombosis or pulmonary thrombosis during pregnancy or post partum. CONCLUSION: Venous thromboembolism prophylaxis may be warranted for pregnant women with prior superficial vein thrombosis. Smoking cessation should be recommended, especially during pregnancy and the postpartum period.     

Venous thromboembolism as a cause of severe maternal morbidity and mortality in the United States

In the U.S., deaths due to pulmonary embolism (PE) account for 9.2% of all pregnancy-related deaths or approximately 1.5 deaths per 100,000 live births. Maternal deaths and maternal morbidity due to PE are more common among women who deliver by cesarean section. In the past decade, the clinical community has increasingly adopted venous thromboembolism (VTE) guidelines and thromboprophylaxis recommendations for pregnant women. Although deep vein thrombosis rates have decreased during this time-period, PE rates have remained relatively unchanged in pregnancy hospitalizations and as a cause of maternal mortality. Changes in the health profile of women who become pregnant, particularly due to maternal age and co-morbidities, needs more attention to better understand the impact of VTE risk during pregnancy and the postpartum period.     

Recommendations for the diagnosis and treatment of deep venous thrombosis and pulmonary embolism in pregnancy and the postpartum period

Venous thromboembolism (VTE) in pregnancy and the postpartum is an important cause of maternal morbidity and mortality; yet, there are few robust data from clinical trials to inform an approach to diagnosis and management. Failure to investigate symptoms suggestive of pulmonary embolism (PE) is a consistent finding in maternal death enquiries, and clinical symptoms should not be relied on to exclude or diagnose VTE. In this consensus statement, we present our recommendations for the diagnosis and management of acute deep venous thrombosis (DVT) and PE. All women with suspected DVT in pregnancy should be investigated with whole leg compression ultrasonography. If the scan is negative and significant clinical suspicion remains, then further imaging for iliofemoral DVT maybe required. Imaging should be undertaken in all women with suspected PE, as the fetal radiation exposure with both ventilation/perfusion scans and CT pulmonary angiography is within safe limits. Low-molecular-weight heparin (LMWH) is the preferred therapy for acute VTE that occur during pregnancy. In observational cohort studies, using once-daily regimens appears adequate, in particular with the LMWH tinzaparin; however, pharmacokinetic data support twice-daily therapy with other LMWH and is recommended, at least initially, for PE or iliofemoral DVT in pregnancy. Treatment should continue for a minimum duration of six months, and until at least six weeks postpartum. Induction of labour or planned caesarean section maybe required to allow an appropriate transition to unfractionated heparin to avoid delivery in women in therapeutic doses of anticoagulation.     

妇产科静脉血栓栓塞症发生的高危因素

静脉血栓栓塞症（VTE）包括深静脉血栓形成（DVT）和肺栓塞（PE）,是妇产科常见的严重并发症,其发展迅速,病死率高。VTE重在风险评估和疾病预防,文章就国内外相关文献,结合自身经验总结妇产科临床常见的VTE高危因素及其潜在机制。     

Thromboembolism and thrombophilia in pregnancy

Venous thromboembolism (VTE) is one of the leading causes of maternal mortality worldwide and is also the cause of significant maternal morbidity. This article discusses the risk factors for VTE in pregnancy, the management of the pregnant woman at risk both antenatally and postpartum and the acute management of VTE when it occurs during pregnancy.The thrombophilias, both heritable and acquired are becoming increasingly recognised as a cause of morbidity and mortality both within and outside pregnancy. There has been recent increased interest in the thrombophilias and their link with recurrent miscarriage, pre-eclampsia, abruption and intrauterine growth restriction. The relationship between the thrombophilias and adverse pregnancy outcome is addressed in detail with reference to the current literature available on this evolving subject.     

Thromboembolism in pregnancy

Venous thromboembolism in pregnancy is a clinical emergency that has been associated with significant risk for maternal and fetal morbidity and mortality. The adaptation of the maternal hemostatic system to pregnancy predisposes women to an increased risk of thromboembolism. A timely diagnosis of deep venous thrombosis is crucial because up to 24% of patients with untreated deep venous thrombosis develop a pulmonary embolism. Recent clinical guidelines identify compression venous ultrasound as the best way to diagnose deep venous thrombosis in pregnancy and CT pulmonary angiography as the best way to diagnose pulmonary embolism in pregnancy. Therapy involves supportive care and anticoagulation with unfractionated or low molecular weight heparin, depending on the clinical scenario.     

产褥期静脉血栓栓塞性疾病的诊断与处理

静脉血栓栓塞性疾病是产褥期妇女严重并发症之一。静脉血栓栓塞性疾病包括深静脉血栓形成及肺栓塞两种。由于该病有潜在致死性,因此早期诊断和规范治疗是改善孕产妇妊娠结局的关键。现就产褥期静脉血栓栓塞性疾病的形成机制、诊断及治疗作一阐述。     

Current management of thromboembolism in pregnancy and puerperium

Venous thromboembolism (VTE) remains the leading cause of maternal death. Today, various risk factors and conditions are known to increase the risk for VTE associated with pregnancy. Having identified the individual risk of a pregnant women, appropriate preventive measures can be taken. If VTE occurs during pregnancy, an appropriate immediate diagnostic work-up is essential in order to avoid further complications. For deep vein thrombosis (DVT) the diagnostic tool of choice is color-coded duplex-sonography, for pulmonary embolism (PE) perfusion/ventilation lung scan can be used. Integrating a detailed individual and family history, the presence of thrombophilia or other risk factors, a risk stratification can be undertaken. These risk categories are defined in the present paper and the appropriate treatment measures are described. As oral anticoagulants cross the placenta and may cause embryopathy in any trimester, oral anticoagulants should be avoided throughout pregnancy. Therefore, heparin is the anti-coagulant of choice for pregnant women, with low molecular weight heparins (LMWH) having distinctive pharmacological advantages over unfractionated heparins. Besides a potential for bleeding, the main side effects of heparin include heparin-induced thrombocytopenia which prompts for platelet monitoring, especially in the first weeks of heparin treatment, and, secondly, heparin-induced osteoporosis, which is a potential sequel of long-term heparin administration. Even though there are abundant reports in the literature on the use of LMWH in pregnant women, that show that they are safe and effective, LMWH are not specifically licensed for the use in pregnancy.     

妊娠相关静脉血栓栓塞症风险评估模型研究进展

妊娠相关静脉血栓栓塞症（pregnancy associated venous thromboembolism，PA-VTE）包括妊娠期和产褥期发生的静脉系统的血栓形成疾病，由深静脉血栓形成（deep vein thrombosis，DVT）和肺栓塞（pulmonary embolism，PE）组成的PA-VTE是发达国家孕产妇发病和死亡的主要原因。采用高效、便捷的风险评估模型评估PA-VTE的发病风险并进行分级预防是目前多个国家推荐的主要措施，但由于各国医学水平、经济发展和传统习惯的不同，各国相继开发风险评估模型或根据实际情况对其他国家的风险评估模型进行改良，进而对妊娠期及产褥期VTE风险进行个体化评估，并实施相应的血栓预防策略。通过回顾国内外的PA-VTE风险评估模型，旨在为我国进一步建立孕产妇的VTE防治指南提供依据，为产科医务工作者制定出适合我国产科人群的VTE风险评估模型提供参考。     

Pulmonary embolus in pregnancy

Venous thromboembolism remains in the top three leading causes of maternal death in the US, representing 10.2% of pregnancy-related deaths. Risk of developing a pulmonary embolus appears to increase throughout pregnancy, with a peak in incidence in the early postpartum period. Overall the incidence of VTE is 0.6–1.8 VTEs per 1000 deliveries. Diagnosis and management of pulmonary embolus can prove challenging, but the aim should be to optimize maternal outcome while minimizing hemorrhagic complications. Low-molecular-weight heparin is a safe and effective treatment for the majority of cases of pregnancy-related pulmonary embolus.     

Incidence,clinical characteristics,and timing of objectively diagnosed venous thromboembolism during pregnancy

Objective: To determine the incidence, timing, and associated clinical characteristics of objectively diagnosed pregnancy-associated venous thromboembolism (VTE).Methods: A retrospective review of VTE cases occurring between 1978 and 1996 was performed. Cases of deep venous thrombosis (DVT) and pulmonary embolism (PE) were identified by ICD-9 discharge diagnosis code and review of antepartum and coagulation laboratory databases. Study inclusion criteria required the objective diagnosis of VTE with either Doppler ultrasound, impedance plethysmography, pulmonary angiography, ventilation-perfusion scanning, or CT/MRI.Results: Among 268,525 deliveries there were 165 (0.06%) episodes of VTE (1/1627 births). There were 127 cases of DVT and 38 cases of PE. Only 14% (23/165) had a prior history of DVT or PE. Most DVTs occurred in the left leg (104/127, 81.9%). Nearly three quarters of the DVTs (95/127, 74.8%) occurred in the antepartum period. Among the antepartum DVT cases, half were detected prior to 15 weeks of gestation (47/95, 49.5%), with only 28 cases occurring after 20 weeks (P < .0001). The majority of the PEs occurred in the postpartum period (23/38, 60.5%). There were only 3 maternal deaths due to PE, all associated with cesarean section. Only 1 patient developed PE while on heparin therapy for DVT while 11 others had complications attributable to heparin use.Conclusion: Most pregnancy-related VTE occurs in the antepartum period. The risk of deep venous thrombosis appears to begin early in pregnancy, even before the second trimester. The highest risk period for pulmonary embolism is after cesarean delivery. Maternal complications of heparin anticoagulation during pregnancy are rare.     

Thromboembolism and thrombophilia in pregnancy

Venous thromboembolism (VTE) is one of the leading causes of maternal mortality worldwide and is also the cause of significant maternal morbidity. This article discusses the risk factors for VTE in pregnancy, the management of the pregnant woman at risk both antenatally and post-partum, and the acute management of VTE when it occurs during pregnancy.The thrombophilias, both heritable and acquired, are becoming increasingly recognised as a cause of morbidity and mortality both within and outside pregnancy. There has been a recent increased interest in the thrombophilias and their link with recurrent miscarriage, preeclampsia, abruption and intrauterine growth restriction. The relationship between the thrombophilias and adverse pregnancy outcome is addressed in detail, with reference to the current literature available on this evolving subject.     

Risk of venous thrombo-embolic events in pregnant patients with cancer

Objective: Venous thromboembolism (VTE) is one of the leading causes of pregnancy-associated death in the Western world. Cancer is a known risk factor for thrombosis outside of pregnancy. The objective of this study is to evaluate the effect of cancer on the risk of VTE, including deep vein thrombosis (DVT) and pulmonary embolism (PE) in pregnancy.

Methods: We conducted a retrospective population-based cohort study using the Health Care Cost and Utilization Project database from 2003 to 2011. Risk of developing DVT, PE and VTE among pregnant patients with the 10 most prevalent malignancies was measured using unconditional logistic regression analysis.

Results: A total of 2826 women were identified with underlying malignancies, among our study cohort of 7?917?453 women. Risk of VTE was increased among pregnant patients with cervical cancer (OR 8.64, 95% CI (2.15–34.79)), ovarian cancer (OR 10.35, 95% CI (1.44–74.19)), Hodgkin’s disease (OR 7.87, 95% CI (2.94–21.05)) and myeloid leukemia (OR 20.75, 95% CI (6.61–65.12)). There was no increased risk of VTE among women with brain cancer, thyroid cancer, melanoma and lymphoid leukemia.

Conclusion: Many cancers may increase risk of VTE in pregnancy. Appropriate thromboprophylaxis should be considered in some of these women, particularly those with hematological malignancies and gynecologic cancers.     

Low-molecular-weight heparins for the prevention and treatment of venous thromboembolism in at-risk pregnant women: a review

Certain pregnant populations are at high risk of developing venous thromboembolism (VTE) during pregnancy. Patients at particularly high risk of VTE are those with a history of VTE, thrombophilia or adverse pregnancy outcomes or with mechanical heart valves. In these high-risk patients, evidence-based guidelines recommend the use of thromboprophylaxis. Low-molecular-weight heparin (LMWH) is a safe and effective thromboprophylaxis option in these patients and has a number of administrative and pharmacokinetic advantages over unfractionated heparin. Furthermore, LMWH has also been shown to be a safe and effective treatment for confirmed deep vein thrombosis in pregnant women.     

The acute management of venous thromboembolism in pregnancy.

Pulmonary thromboembolism is the leading cause of maternal death in the UK. Optimal management of deep venous thrombosis and pulmonary thromboembolism requires an appreciation of risk factors, particularly thrombophilia, and signs or symptoms suggestive of venous thromboembolism, along with objective diagnosis and treatment with anticoagulants. Low molecular weight heparins are now replacing unfractionated heparin for the treatment of deep venous thrombosis and pulmonary thromboembolism in pregnancy because of the lower risk of side effects, ease of administration and reduced need for monitoring.     

血栓性疾病史女性孕前系统管理

既往血栓性疾病史是妊娠女性发生静脉栓塞的首要高危因素,其造成的肺栓塞是危及孕妇生命的主要原因,同时血栓性疾病史孕妇也是子痫前期、死胎、胎盘早剥等不良妊娠并发症的高危人群。对这些人群进行系统孕前管理是减少或杜绝此类恶性事件发生的关键。     

United Kingdom recommendations for obstetric venous thromboembolism prophylaxis: Evidence and rationale

Venous thromboembolism (VTE) is a leading cause of maternal death in the United Kingdom. To address this problem guidance from the Royal College of Obstetricians and Gynaecologists (RCOG) has been developed that recommends the assessment of a woman's risk of thrombosis at specific time-points during pregnancy and postnatally at the time of delivery. The RCOG guidelines provide clinicians with a framework to inform decision-making on the use of thromboprophylaxis and are based on the premise that the higher risk a woman has for VTE, the more likely she is to benefit from prophylaxis – determining her level of risk is based on the number and characteristics of the risk factors that she has. This article will address the pathophysiology of VTE in pregnancy, evidence behind the risk factors for VTE and the use of thromboprophylactic agents. Further, it will reflect on the rationale behind the RCOG guidance.     

妇科围手术期静脉血栓栓塞症的预防

静脉血栓栓塞症（VTE）包括深静脉血栓形成和肺栓塞,是妇科常见的围手术期并发症,严重威胁患者生命安全。如今,VTE已逐渐引起人们的重视,VTE预防不容忽视。结合中国妇科术后VTE防治经验,2017年制定了“妇科手术后深静脉血栓形成及肺栓塞预防专家共识”。文章就妇科围手术期VTE预防的重要性及预防措施进行详解。     

The effect of graduated compression stockings on blood velocity in the deep venous system of the lower limb in the postnatal period

Venous thromboembolism (VTE) is the leading cause of maternal mortality in the UK and is also a major cause of long-term morbidity. Recent UK national guidelines recommend thromboprophylaxis, which includes the use of graduated compression stockings (GCS), for high-risk women to reduce the risk of VTE in both the antenatal and postpartum period. This study of 17 women examined the effects of GCS on the deep venous system in the immediate postpartum period and found a statistically significant reduction in the diameter of the common femoral vein (CFV) (pre- versus post stocking diameter: mean 10.39 mm [SD 2.09] versus mean 9.69 mm [SD 1.99]) and an increase in the rate of blood velocity in the CFV (pre- versus post stocking velocity: mean 10.0 cm/s [SD 2.7] versus 13.9 cm/s [SD 4.2]) 30 minutes after application of thigh length GCS in women 1 or 2 days following a singleton vaginal delivery at term. This confirms reduction in venous stasis in the deep venous system in the immediate postpartum woman by the use of GCS, supporting their use in improving venous function in this context.