The intial diagnostic test in a pregnant woman suspected to have a pulmonary embolism (PE) depends on the presence or absence of leg symptoms suggestive of deep vein thrombosis (DVT). Compression ultrasonography is not the routine initial method of evaluation in a suspected PE during pregnancy unless the patient has coexisting symptoms and signs of DVT.[1] In case the compression ultrasound is negative for DVT and there is persistent clinical suspicion of PE, the negative ultrasound does not rule out PE and additional imaging tests are required.[1] If leg symptoms are absent in a pregnant woman suspected to have PE, a chest X-ray is the initial imaging modality.[1] When anticoagulation is indicated for the prevention or treatment of venous thromboembolism in pregnancy, low molecular weight heparin (LMWH) should be administered instead of vitamin K antagonists (VKA).[2] In fact, VKA can cross the placenta and lead to embryopathy as well as fetal loss. Some of the teratogenic effect of VKA include midfacial hypoplasia, stippled epiphysis, and limb hypoplasia.[2][3][4] The teratogenic effect of VKA is particularly important during the first trimester of pregnancy.[2]
2012 VTE, Thrombophilia, Antithrombotic Therapy, and Pregnancy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (DO NOT EDIT)[2]
"1. For lactating women using warfarin, acenocoumarol, or UFH who wish to breast-feed, we recommend continuing the use of warfarin, acenocoumarol, or UFH. (Level of Evidence: A) '"
"2. For lactating women using LMWH, danaparoid, or r-hirudin who wish to breast-feed, we recommend continuing the use of LMWH, danaparoid, or r-hirudin. (Level of Evidence: B) '"
"3. For breast-feeding women, we recommend alternative anticoagulants rather than oral direct thrombin (eg, dabigatran) and factor Xa inhibitors (eg, rivaroxaban, apixaban). (Level of Evidence: C) '"
"2. For lactating women using low-dose aspirin for vascular indications who wish to breast-feed, we suggest continuing this medication. (Level of Evidence: C)"
VTE in Patients Using Assisted Reproductive Technology
"1. For women undergoing assisted reproduction who develop severe ovarian hyperstimulation syndrome, we suggest thrombosis prophylaxis (prophylactic LMWH) for 3 months postresolution of clinical ovarian hyperstimulation syndrome rather than no prophylaxis. (Level of Evidence: C)"
"1. For women undergoing cesarean section without additional thrombosis risk factors, we recommend against the use of thrombosis prophylaxis other than early mobilization. (Level of Evidence: B)"
"1. For women at increased risk of VTE after cesarean section because of the presence of one major or at least two minor risk factors, we suggest pharmacologic thromboprophylaxis (prophylactic LMWH) or mechanical prophylaxis (elastic stockings or intermittent pneumatic compression) in those with contraindications to anticoagulants while in hospital following delivery rather than no prophylaxis. (Level of Evidence: B)"
"3. For selected high-risk patients in whom significant risk factors persist following delivery, we suggest extended prophylaxis (up to 6 weeks after delivery) following discharge from the hospital. (Level of Evidence: C)"
"3. For pregnant women receiving adjusted-dose LMWH therapy and where delivery is planned, we recommend discontinuation of LMWH at least 24 h prior to induction of labor or cesarean section (or expected time of neuraxial anesthesia) rather than continuing LMWH up until the time of delivery. (Level of Evidence: B)"
"1. For pregnant women with acute VTE, we suggest that anticoagulants should be continued for at least 6 weeks postpartum (for a minimum total duration of therapy of 3 months) in comparison with shorter durations of treatment. (Level of Evidence: C)"
Prevention of VTE in Pregnant Women With Prior DVT or PE
"1. For all pregnant women with prior VTE, we suggest postpartum prophylaxis for 6 weeks with prophylactic- or intermediate-dose LMWH or vitamin K antagonists targeted at INR 2.0 to 3.0 rather than no prophylaxis. (Level of Evidence: B)"
"2. For pregnant women at low risk of recurrent VTE (single episode of VTE associated with a transient risk factor not related to pregnancy or use of estrogen), we suggest clinical vigilance antepartum rather than antepartum prophylaxis. (Level of Evidence: C)"
"3. For pregnant women at moderate to high risk of recurrent VTE (single unprovoked VTE, pregnancy- or estrogen-related VTE, or multiple prior unprovoked VTE not receiving long-term anticoagulation), we suggest antepartum prophylaxis with prophylactic- or intermediate-dose LMWH rather than clinical vigilance or routine care. (Level of Evidence: C)"
"4. For pregnant women receiving long-term vitamin K antagonists, we suggest adjusted-dose LMWH or 75% of a therapeutic dose of LMWH throughout pregnancy followed by resumption of long-term anticoagulants postpartum, rather than prophylactic-dose LMWH. (Level of Evidence: C)"
Prevention of VTE in Pregnant Women With Thrombophilia and No Prior VTE
"1. For pregnant women with no prior history of VTE who are known to be homozygous for factor V Leiden or the prothrombin 20210A mutation and have a positive family history for VTE, we suggest antepartum prophylaxis with prophylactic- or intermediate-dose LMWH and postpartum prophylaxis for 6 weeks with prophylactic- or intermediate-dose LMWH or vitamin K antagonists targeted at INR 2.0 to 3.0 rather than no prophylaxis. (Level of Evidence: B)"
"2. For pregnant women with all other thrombophilias and no prior VTE who have a positive family history for VTE, we suggest antepartum clinical vigilance and postpartum prophylaxis with prophylactic- or intermediate-dose LMWH or, in women who are not protein C or protein S|S]] deficient, vitamin K antagonists targeted at INR 2.0 to 3.0 rather than routine care. (Level of Evidence: C)"
"3. For pregnant women with no prior history of VTE who are known to be homozygous for factor V Leiden or the prothrombin 20210A mutation and who do not have a positive family history for VTE, we suggest antepartum clinical vigilance and postpartum prophylaxis for 6 weeks with prophylactic- or intermediate-dose LMWH or vitamin K antagonists targeted at INR 2.0 to 3.0 rather than routine care. (Level of Evidence: B)"
"4. For pregnant women with all other thrombophilias and no prior VTE who do not have a positive family history for VTE, we suggest antepartum and postpartum clinical vigilance rather than pharmacologic prophylaxis. (Level of Evidence: C)"
"1. For women with recurrent early pregnancy loss (three or more miscarriages before 10 weeks of gestation), we recommend screening for APLAs. (Level of Evidence: B)"
"2. For women who fulfill the laboratory criteria for APLA syndrome and meet the clinical APLA criteria based on a history of three or more pregnancy losses, we recommend antepartum administration of prophylactic- or intermediate-dose UFH or prophylactic LMWH combined with low-dose aspirin, 75 to 100 mg/d, over no treatment. (Level of Evidence: B)"
"1. For women with a history of pregnancy complications, we suggest not to screen for inherited thrombophilia. (Level of Evidence: C)"
"2. For women with inherited thrombophilia and a history of pregnancy complications, we suggest not to use antithrombotic prophylaxis. (Level of Evidence: C)"
Management of Women With a History of Preeclampsia or Recurrent Fetal Loss and No Thrombophilia
"2. For women with two or more miscarriages but without APLA or thrombophilia, we recommend against antithrombotic prophylaxis. (Level of Evidence: B)"
Maternal and Fetal Risks Related to Anticoagulation During Pregnancy for Mechanical Prosthetic Valves
(a) Adjusted-dose bid LMWH throughout pregnancy. We suggest that doses be adjusted to achieve the manufacturer’s peak anti-Xa LMWH 4 h postsubcutaneous-injection or
(b) Adjusted-dose UFH throughout pregnancy administered subcutaneously every 12 h in doses adjusted to keep the mid-interval aPTT at least twice control or attain an anti-Xa heparin level of 0.35 to 0.70 units/mL or
(c) UFH or LMWH (as above) until the 13th week, with substitution by vitamin K antagonists until close to delivery when UFH or LMWH is resumed."
