Prolonged bedrest during pregnancy: does the risk of deep vein thrombosis warrant the use of routine heparin prophylaxis?

Venous Thromboembolism in Pregnancy: Challenges and Solutions

Venous thromboembolism (VTE) is a serious medical condition that can lead to severe morbidity and mortality, making it a significant public health concern. VTE is a multifactorial condition that results from the interaction of genetic, acquired, and environmental factors. Physiological changes during pregnancy increase the risk of VTE as they express Virchow's triad (increased coagulation factors, decreased fibrinolysis, trauma, and venous stasis). Moreover, pregnancy-related risk factors, such as advanced maternal age, obesity, multiple gestations, and cesarean delivery, further increase the risk of VTE. Managing VTE in pregnancy is challenging due to the complexity of balancing the risks and benefits of anticoagulant therapy for both the mother and the fetus. A multidisciplinary approach involving obstetricians, hematologists, and neonatologists, is necessary to ensure optimal outcomes for both the mother and baby. This review aims to discuss the current challenges associated with VTE in pregnancy and identify potential solutions for improving outcomes for pregnant women at risk for VTE.

Axillary vein thrombosis 30 h after caesarean section: a case report and literature review

BACKGROUND

Axillary vein thrombosis is a very rare disorder. However, a case of axillary vein thrombosis shortly after caesarean section has not been reported previously. We report a case of axillary vein thrombosis 30 h after caesarean section due to an unidentified aetiology.

CASE

A 37-year-old multiparous woman developed swelling and pain of the forearm and hand 30 h after undergoing a caesarean section. Doppler ultrasonography revealed a 14.9 mm × 5.3 mm thrombosis in the left axillary vein although a prophylaxis of anticoagulation was administrated. After an adjusted-dose of low-molecular-weight heparin (LMWH) was administered, the patient recovered and was discharged.

CONCLUSION

Obstetricians should be fully aware of the possibility of upper extremity deep vein thrombosis (DVT) despite its rarity, especially after the surgery. Lying in the lateral decubitus position for long periods postoperatively should be avoided as much as possible.

Portal vein thrombosis after cesarean section in a patient on prolonged bed rest due to threatened preterm labor

Portal vein thrombosis is a rare but life-threatening complication during pregnancy and postpartum period. Color Doppler ultrasound is useful for prompt diagnosis. Although the risk of complications should be considered, successful pregnancy with comorbid portal vein thrombosis is possible with appropriate anticoagulation therapy and close monitoring.

Risk factors for venous thromboembolism in 1.3 million pregnancies: a nationwide prospective cohort

Objective

To quantify risk factors for venous thromboembolism during pregnancy and the puerperal period.

Design

In a nationwide prospective cohort study we followed pregnant and puerperal women in Denmark from 1995 to 2009 for venous thromboembolism. Information on risk factors and confounders was retrieved from national registries. The diagnosis of venous thromboembolism was confirmed through medical charts. We calculated adjusted incidence rates per 10,000 women years and used Poisson regression to estimate effects during pregnancy and the puerperal period.

Results

We studied 1,297,037 pregnancies and related puerperal periods, during which there were 748 venous thromboembolisms. The incidence rate for venous thromboembolism during a pregnancy with and without hospitalization for hyperemesis was 15.2/10,000 yr and 6.3/10,000 yr, respectively, (adjusted rate ratio: 2.5 (95%-confidence interval; 1.4–4.5)). The incidence rate among women with multiple pregnancies was 18.2/10,000 yr and 6.3/10,000 yr in singletons (adjusted rate ratio: 2.8 (1.9–4.2)). Increased risk was found with hospitalization during pregnancy or the puerperal period with incidence rates of 42.1/10.000 and 54.7/10.000, respectively, (rate ratios: 12.2 (8.7–17) and 5.9 (4.0–8.8)). Women hospitalized with infections during pregnancy had incidence rates of 25.9/10,000 yr and 29.3/10,000 yr during pregnancy and the puerperal period, respectively, and of 62.7/10,000 yr if hospitalized with infection in the puerperal period. Puerperal venous thromboembolism was associated with hospitalization for preeclampsia and intrauterine growth restriction/fetal death with incidence rates of 45.8/10,000 yr and 18.3/10,000 yr, respectively (rate ratio: 5.0 (3.1–7.8) and 1.9 (0.9–4.4)). Additionally puerperal venous thromboembolism was associated with obesity, elective and acute caesarean sections and major postpartum bleeding with incidence rates of 25.5/10,000 yr, 23.2/10,000 yr, 34.0/10,000 yr and 20.3/10,000 yr, respectively (rate ratios 1.7 (1.1–2.7), 2.1 (1.4–3.1), 3.0 (2.3–4.0) and 1.4 (1.0–2.1)).

Conclusions

Important risk factors for venous thromboembolism during pregnancy or the puerperal period were hospitalization, infection, hyperemesis, multiple pregnancies, preeclampsia, obesity, caesarean section, major postpartum bleeding, and intrauterine growth restriction or fetal death.

Pregnancy-associated thrombosis

The main reason for the increased risk of thromboembolism in pregnancy is hypercoagulability, which has likely evolved to protect women from the bleeding challenges of miscarriage and childbirth. Women are at a 4- to 5-fold increased risk of thromboembolism during pregnancy and the postpartum period compared with when they are not pregnant. Eighty percent of the thromboembolic events in pregnancy are venous, with an incidence of 0.49 to 1.72 per 1000 pregnancies. Risk factors include a history of thrombosis, inherited and acquired thrombophilia, maternal age greater than 35, certain medical conditions, and various complications of pregnancy and childbirth. Despite the increased risk of venous thromboembolism (VTE) during pregnancy and the postpartum period, most women do not require anticoagulation. Candidates include women with current VTE, a history of VTE, thrombophilia and a history of poor pregnancy outcome, or risk factors for postpartum VTE. The intensity of the anticoagulation will depend on the indication and the monitoring will depend on the intensity. At the time of delivery, anticoagulation should be manipulated to reduce the risk of bleeding complications while minimizing the risk of thrombosis. There are no large trials of anticoagulants in pregnancy, and recommendations are based on case series, extrapolations from nonpregnant patients and the opinion of experts. Nonetheless, anticoagulants are believed to improve the outcome of pregnancy for women who have, or have had, VTE.

Ante- and postnatal risk factors of venous thrombosis: a hospital-based case-control study

OBJECTIVE

To study ante- and postnatal risk factors of venous thrombosis (VT) in pregnancy.

METHODS

A hospital-based case-control study. Cases were women with objectively verified VT during pregnancy or postpartum. Two controls were selected for each case. Validated risk factors were analyzed using chi-square test and logistic regression.

RESULTS

In total 559 cases with no prior VT, 268 ante- and 291 postnatal cases were identified together with 1229 controls. Risk factors for antenatal VT were assisted reproduction technique (ART), antepartum immobilization, cigarette smoking, and slight weight gain (<7 kg). Conception after ART and multiple pregnancy had an additive effect, whereas antepartum immobilization and high body mass index (BMI) had a multiplicative effect on the risk for antepartum VT. No other interaction was found between risk factors for antepartum VT. Risk factors for postnatal VT were antepartum immobilization, cigarette smoking, intrauterine fetal growth restriction (IUGR), preeclampsia, emergency cesarean section, postpartum hemorrhage, infection, surgery, and age and parity. Antepartum immobilization, high BMI and reoperation on the indication of bleeding showed multiplicative effects on the risk of postnatal VT.

CONCLUSIONS

Ante- and postpartum risk factors differed markedly. More attention should be paid to pregnant women of high BMI who are immobilized.

Prevention and management of venous thromboembolism in pregnancy

Normal pregnancy is accompanied by an increase in clotting factors. The resulting hypercoagulable state has likely evolved to protect women from hemorrhage at the time of miscarriage and childbirth. During pregnancy, women are 4 times more likely to suffer from venous thromboembolism (VTE) compared with when they are not pregnant. Relative to pregnancy, the risk postpartum is even higher. The incidence of VTE is approximately 2 per 1,000 births, and VTE accounts for 1 death per 100,000 births, or approximately 10% of all maternal deaths. The most important risk factors during pregnancy are thrombophilia and a history of thrombosis. A history of thrombosis increases the risk for VTE to 2% to 12%. Thrombophilia increases not only the risk for maternal thrombosis but also the risk of poor pregnancy outcome. Despite the increased risk for thrombosis during pregnancy and the postpartum period, most women do not require anticoagulation. Those who do require anticoagulation include women with current VTE, women on lifelong anticoagulation, and many women with thrombophilia or a history of thrombosis. Recommended options for anticoagulation in pregnancy are limited to heparins, which do not cross the placenta. Low-molecular-weight heparin (LMWH) is preferred over unfractionated heparin because LMWH has a longer half-life and is presumed to have fewer side effects. The longer half-life is a disadvantage around the time of delivery, when unfractionated heparin, with its shorter half-life, is easier to manage. For women who develop or are at high risk for heparin-induced thrombocytopenia or severe cutaneous reactions, fondaparinux is probably the agent of choice. Women who do not require lifelong anticoagulation, but require anticoagulation during pregnancy, will still require anticoagulation for the first 6 weeks postpartum.

Venous Thromboembolism in Obstetrics and Gynecology

The diagnosis of venous thromboembolism can present a clinical challenge. Using D-dimer testing and spiral or helical computed tomography scans has simplified the diagnosis of venous thromboembolism. In addition, the use of low molecular weight heparin has become widely accepted in the prevention and treatment of venous thromboembolism. However, further studies are needed to determine optimal prevention and treatment strategies, particularly in the obstetric population.

Maladie thromboembolique périopératoire et obstétricale. Pathologie gynécologique et obstétricale

Venous thromboembolism is a leading cause of maternal mortality in many countries, including France. Most enquiries have repeatedly demonstrated that many deaths could be avoided, suggesting the need to update and ensure a wider diffusion of recommendations. Although thromboembolism-induced maternal death plays a major role, the absolute incidence of events remains low, reducing the ability to perform well-designed research and the level of recommendations presented. Many personal or pregnancy-related factors have been identified as increasing the risk of thromboembolism in pregnant patients but few of them have been associated with a significantly increased risk. A history of thromboembolic event and some thrombophilic factors (including antithrombin deficiency and antiphospholipid syndrome) carry the greatest risk. Pregnancy itself, caesarean delivery and the postpartum period, although associated with an increased risk play a minor role when not combined with other risk factors. Prophylactic treatment relies mainly on low molecular weight heparins which safety is now well established in pregnant patients. Dose and duration of treatment should be adapted to the perceived level of risk. The occurrence of a thromboembolic event is also increased after gynaecological surgery but major and cancer surgery carry the greatest risk. Here also, low molecular weight heparins play a leading role, although non pharmacologic means are useful. Dose and duration should be dependent on the level of risk.