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==Overview==
==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)<ref name="pmid22315276">{{cite journal| author=Bates SM, Greer IA, Middeldorp S, Veenstra DL, Prabulos AM, Vandvik PO et al.| title=VTE, thrombophilia, antithrombotic therapy, and pregnancy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. | journal=Chest | year= 2012 | volume= 141 | issue= 2 Suppl | pages= e691S-736S | pmid=22315276 | doi=10.1378/chest.11-2300 | pmc=PMC3278054 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22315276 }} </ref>==
Venous thromboembolism (VTE) consists of deep vein thrombosis (DVT), pulmonary embolism (PE), or both.  The risk factors for VTE are a constellation of predisposing conditions which stem from the three principles of [[Virchow's triad]]: stasis of the blood flow, damage to the vascular [[endothelial cell]]s, and [[hypercoagulability]].  The risk factors for VTE can be classified as temporary, modifiable and non-modifiable.  It is suggested that [[venous thrombosis]] also shares risk factors with [[artery thrombosis]], such as [[obesity]], [[hypertension]], [[smoking]], and [[diabetes mellitus]].<ref name="pmid20620709">{{cite journal| author=Goldhaber SZ| title=Risk factors for venous thromboembolism. | journal=J Am Coll Cardiol | year= 2010 | volume= 56 | issue= 1 | pages= 1-7 | pmid=20620709 | doi=10.1016/j.jacc.2010.01.057 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20620709 }} </ref>
===Maternal Complications of Anticoagulant Therapy===
2.2.1. For pregnant patients, we recommend LMWH for the prevention and treatment of VTE, instead of UFH (Grade 1B).


==Risk Factors==
===Fetal Complications of Antithrombotic Therapy During Pregnancy===
3.0.1. For women receiving anticoagulation for the treatment of VTE who become pregnant, we recommend LMWH over vitamin K antagonists during the first trimester (Grade 1A), in the second and third trimesters (Grade 1B), and during late pregnancy when delivery is imminent (Grade 1A).


Shown below is a list of predisposing factors to [[VTE]].<ref name="pmid12814980">{{cite journal| author=Anderson FA, Spencer FA| title=Risk factors for venous thromboembolism. | journal=Circulation | year= 2003 | volume= 107 | issue= 23 Suppl 1 | pages= I9-16 | pmid=12814980 | doi=10.1161/01.CIR.0000078469.07362.E6 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=12814980  }} </ref><ref name="pmid18757870">{{cite journal| author=Torbicki A, Perrier A, Konstantinides S, Agnelli G, Galiè N, Pruszczyk P et al.| title=Guidelines on the diagnosis and management of acute pulmonary embolism: the Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology (ESC). | journal=Eur Heart J | year= 2008 | volume= 29 | issue= 18 | pages= 2276-315 | pmid=18757870 | doi=10.1093/eurheartj/ehn310 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18757870  }} </ref> The risk factors are classified as strong, moderate and weak depending on how strongly they predispose for a VTE.
3.0.2. For women requiring long-term vitamin K antagonists who are attempting pregnancy and are candidates for LMWH substitution, we suggest performing frequent pregnancy tests and substituting LMWH for vitamin K antagonists when pregnancy is achieved rather than switching to LMWH while attempting pregnancy (Grade 2C).


{| style="cellpadding=0; cellspacing= 0; width: 600px;"
3.0.3. For pregnant women, we suggest limiting the use of fondaparinux and parenteral direct thrombin inhibitors to those with severe allergic reactions to heparin (eg, HIT) who cannot receive danaparoid (Grade 2C).
|-
| style="padding: 0 5px; font-size: 100%; background: #F5F5F5;" align=center |'''Strong risk factors'''|| style="padding: 0 5px; font-size: 100%; background: #F5F5F5;" align=center |'''Moderate risk factors''' || style="padding: 0 5px; font-size: 100%; background: #F5F5F5;" align=center |'''Weak risk factors'''
|-
|  style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left |❑ [[Bone fracture]] ([[hip]] or [[leg]]) <br>
❑ [[Hip replacement surgery]]<br>
❑ Knee replacement surgery<br>
❑ [[General surgery|Major general surgery]]<br>
❑ [[Trauma|Significant trauma]]<br>
❑ [[Spinal cord injury]]<br>
|  style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left |❑ Athroscopic knee surgery<br>
❑ [[Central venous line]]s<br>
❑ [[Chemotherapy]]<br>
❑ [[Chronic heart failure]]<br>
❑ [[Respiratory failure]]<br>
❑ [[Hormone replacement therapy]]<br>
❑ [[Cancer]]<br>
❑ [[Oral contraceptive pills]] <br>
❑ [[Stroke]] <br>
❑ [[Pregnancy]] <br>
❑ [[Postpartum]] <br>
❑ Prior history of [[VTE]] <br>
❑ [[Thrombophilia]] <br>
| style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left |❑ Bed rest for more than 3 days <br>
❑ Prolonged car or air travel <br>
❑ Advanced [[age]] <br>
❑ [[Laparoscopic surgery]] <br>
❑ Prepartum <br>
❑ [[Obesity]] <br>
❑ [[Varicose veins]]
|}


The risk factors of VTE can be further classified into modifiable, non-modifiable and temporary.
3.0.4. For pregnant women, we recommend avoiding the use of oral direct thrombin (eg, dabigatran) and anti-Xa (eg, rivaroxaban, apixaban) inhibitors (Grade 1C).


===Modifiable Risk Factors===
===Use of Anticoagulants in Breast-feeding Women===
Modifiable risk factors are reversible based upon lifestyle/behavior modification.
4.0.1. For lactating women using warfarin, acenocoumarol, or UFH who wish to breast-feed, we recommend continuing the use of warfarin, acenocoumarol, or UFH (Grade 1A).
* Obesity: [[Obesity]] is defined as a body-mass index (BMI) above 30 kg/m2.<ref name="pmid20404252">{{cite journal| author=Holst AG, Jensen G, Prescott E| title=Risk factors for venous thromboembolism: results from the Copenhagen City Heart Study. | journal=Circulation | year= 2010 | volume= 121 | issue= 17 | pages= 1896-903 | pmid=20404252 | doi=10.1161/CIRCULATIONAHA.109.921460 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20404252  }} </ref> <ref name="pmid21352080">{{cite journal| author=Vayá A, Martínez-Triguero ML, España F, Todolí JA, Bonet E, Corella D| title=The metabolic syndrome and its individual components: its association with venous thromboembolism in a Mediterranean population. | journal=Metab Syndr Relat Disord | year= 2011 | volume= 9 | issue= 3 | pages= 197-201 | pmid=21352080 | doi=10.1089/met.2010.0117 | pmc= | url= }} </ref> <ref name="pmid18695082">{{cite journal| author=Eichinger S, Hron G, Bialonczyk C, Hirschl M, Minar E, Wagner O et al.| title=Overweight, obesity, and the risk of recurrent venous thromboembolism. | journal=Arch Intern Med | year= 2008 | volume= 168 | issue= 15 | pages= 1678-83 | pmid=18695082 | doi=10.1001/archinte.168.15.1678 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18695082  }} </ref>


* [[Smoking]]:<ref name="pmid20404252">{{cite journal| author=Holst AG, Jensen G, Prescott E| title=Risk factors for venous thromboembolism: results from the Copenhagen City Heart Study. | journal=Circulation | year= 2010 | volume= 121 | issue= 17 | pages= 1896-903 | pmid=20404252 | doi=10.1161/CIRCULATIONAHA.109.921460 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20404252  }} </ref> Smoking significantly increases the risk of [[DVT]], particularly in women who are taking [[oral contraceptive pills]] as well as among obese people.
4.0.2. 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 (Grade 1B).


* Use of [[oral contraceptives]]<ref name="pmid17726684">{{cite journal| author=Pomp ER, Rosendaal FR, Doggen CJ| title=Smoking increases the risk of venous thrombosis and acts synergistically with oral contraceptive use. | journal=Am J Hematol | year= 2008 | volume= 83 | issue= 2 | pages= 97-102 | pmid=17726684 | doi=10.1002/ajh.21059 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=17726684  }} </ref>
4.0.3. For breast-feeding women, we suggest alternative anticoagulants rather than fondaparinux (Grade 2C).


* Prolonged travel: Travel by air increases the risk to the same extent as travel by bus, train or car, suggesting that the increased risk of air travel is due primarily to prolonged immobility.<ref>http://wwwnc.cdc.gov/travel/yellowbook/2012/chapter-2-the-pre-travel-consultation/deep-vein-thrombosis-and-pulmonary-embolism.htm</ref>
4.0.4. For breast-feeding women, we recommend alternative anticoagulants rather than oral direct thrombin (eg, dabigatran) and factor Xa inhibitors (eg, rivaroxaban, apixaban) (Grade 1C).


* [[Hyperhomocysteinemia]]:<ref name="pmid8592549">{{cite journal| author=den Heijer M, Koster T, Blom HJ, Bos GM, Briet E, Reitsma PH et al.| title=Hyperhomocysteinemia as a risk factor for deep-vein thrombosis. | journal=N Engl J Med | year= 1996 | volume= 334 | issue= 12 | pages= 759-62 | pmid=8592549 | doi=10.1056/NEJM199603213341203 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8592549  }} </ref> [[Hyperhomocysteinemia]] can be reduced with vitamin B supplementation.
4.0.5. For lactating women using low-dose aspirin for vascular indications who wish to breast-feed, we suggest continuing this medication (Grade 2C).


===Non-Modifiable Risk Factors===
===VTE in Patients Using Assisted Reproductive Technology===
* Advanced age
5.1.1. For women undergoing assisted reproduction, we recommend against the use of routine thrombosis prophylaxis (Grade 1B).
* [[Heart failure]]
* [[Thrombophilia]] or [[hypercoagulable state]]
** [[Factor V Leiden]]
** [[Prothrombin G20210A mutation]]
** [[Protein C deficiency]]
** [[protein S deficiency]]
** [[Antithrombin deficiency]]
** [[Activated protein C resistance]]
** [[Antithrombin III deficiency]]
** [[Factor VIII]] mutation
** [[Antiphospholipid syndrome]]
** [[Heparin induced thrombocytopenia]]
** [[Nephrotic syndrome]]
** [[Paroxysmal nocturnal hemoglobinuria]]
* [[Polycythemia vera]]


===Temporary Risk Factors===
5.1.2. 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 (Grade 2C).
* Injury to a deep vein from [[surgery]], a fracture, or other [[trauma]], especially a paralytic spinal cord injury<ref name="pmid12814980">{{cite journal |author=Anderson FA, Spencer FA |title=Risk factors for venous thromboembolism |journal=Circulation |volume=107 |issue=23 Suppl 1 |pages=I9–16 |year=2003 |month=June |pmid=12814980 |doi=10.1161/01.CIR.0000078469.07362.E6 |url=}}</ref>
* Prolonged immobilization that causes [[stasis]] in the deep veins which may occur after surgery, with prolonged bedrest, or prolonged seating during travel
* [[Pregnancy]] and the peri-partum period
* Active [[cancer]]
* [[Central venous catheter]]


==References==
 
{{Reflist|2}}
===VTE Following Cesarean Section===
6.2.1. For women undergoing cesarean section without additional thrombosis risk factors, we recommend against the use of thrombosis prophylaxis other than early mobilization (Grade 1B).
 
6.2.2. 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 (Grade 2B).
 
6.2.3. For women undergoing cesarean section who are considered to be at very high risk for VTE and who have multiple additional risk factors for thromboembolism that persist in the puerperium, we suggest that prophylactic LMWH be combined with elastic stockings and/or intermittent pneumatic compression over LMWH alone (Grade 2C).
 
6.2.4. 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 (Grade 2C).
 
===Treatment of Proven Acute VTE During Pregnancy===
7.1.1. For pregnant women with acute VTE, we recommend therapy with adjusted-dose subcutaneous LMWH over adjusted-dose UFH (Grade 1B).
 
7.1.2. For pregnant women with acute VTE, we recommend LMWH over vitamin K antagonist treatment antenatally (Grade 1A).
 
7.1.3. 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 (Grade 2C).
 
7.1.4. 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 (Grade 1B).
 
===Prevention of VTE in Pregnant Women With Prior DVT or PE===
8.2.1. 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 (Grade 2B).
 
8.2.2. 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 (Grade 2C).
 
8.2.3. 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 (Grade 2C).
 
8.2.4. 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 (Grade 2C).
 
===Prevention of VTE in Pregnant Women With Thrombophilia and No Prior VTE===
9.2.1. 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 (Grade 2B).
 
9.2.2. 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 S deficient, vitamin K antagonists targeted at INR 2.0 to 3.0 rather than routine care (Grade 2C).
 
9.2.3. 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 (Grade 2B).
 
9.2.4. 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 (Grade 2C).
 
===Thrombophilia and Pregnancy Complications===
10.2.1. For women with recurrent early pregnancy loss (three or more miscarriages before 10 weeks of gestation), we recommend screening for APLAs (Grade 1B).
 
10.2.2. For women with a history of pregnancy complications, we suggest not to screen for inherited thrombophilia (Grade 2C).
 
10.2.3. 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 (Grade 1B).
 
10.2.4. For women with inherited thrombophilia and a history of pregnancy complications, we suggest not to use antithrombotic prophylaxis (Grade 2C).
 
===Management of Women With a History of Preeclampsia or Recurrent Fetal Loss and No Thrombophilia===
11.1.1. For women considered at risk for preeclampsia, we recommend low-dose aspirin throughout pregnancy, starting from the second trimester, over no treatment (Grade 1B).
 
11.2.1. For women with two or more miscarriages but without APLA or thrombophilia, we recommend against antithrombotic prophylaxis (Grade 1B).
 
===Maternal and Fetal Risks Related to Anticoagulation During Pregnancy for Mechanical Prosthetic Valves===
12.1.1. For pregnant women with mechanical heart valves, we recommend one of the following anticoagulant regimens in preference to no anticoagulation (all Grade 1A):
 
(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.

Revision as of 21:37, 12 July 2014

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)[1]

Maternal Complications of Anticoagulant Therapy

2.2.1. For pregnant patients, we recommend LMWH for the prevention and treatment of VTE, instead of UFH (Grade 1B).

Fetal Complications of Antithrombotic Therapy During Pregnancy

3.0.1. For women receiving anticoagulation for the treatment of VTE who become pregnant, we recommend LMWH over vitamin K antagonists during the first trimester (Grade 1A), in the second and third trimesters (Grade 1B), and during late pregnancy when delivery is imminent (Grade 1A).

3.0.2. For women requiring long-term vitamin K antagonists who are attempting pregnancy and are candidates for LMWH substitution, we suggest performing frequent pregnancy tests and substituting LMWH for vitamin K antagonists when pregnancy is achieved rather than switching to LMWH while attempting pregnancy (Grade 2C).

3.0.3. For pregnant women, we suggest limiting the use of fondaparinux and parenteral direct thrombin inhibitors to those with severe allergic reactions to heparin (eg, HIT) who cannot receive danaparoid (Grade 2C).

3.0.4. For pregnant women, we recommend avoiding the use of oral direct thrombin (eg, dabigatran) and anti-Xa (eg, rivaroxaban, apixaban) inhibitors (Grade 1C).

Use of Anticoagulants in Breast-feeding Women

4.0.1. For lactating women using warfarin, acenocoumarol, or UFH who wish to breast-feed, we recommend continuing the use of warfarin, acenocoumarol, or UFH (Grade 1A).

4.0.2. 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 (Grade 1B).

4.0.3. For breast-feeding women, we suggest alternative anticoagulants rather than fondaparinux (Grade 2C).

4.0.4. For breast-feeding women, we recommend alternative anticoagulants rather than oral direct thrombin (eg, dabigatran) and factor Xa inhibitors (eg, rivaroxaban, apixaban) (Grade 1C).

4.0.5. For lactating women using low-dose aspirin for vascular indications who wish to breast-feed, we suggest continuing this medication (Grade 2C).

VTE in Patients Using Assisted Reproductive Technology

5.1.1. For women undergoing assisted reproduction, we recommend against the use of routine thrombosis prophylaxis (Grade 1B).

5.1.2. 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 (Grade 2C).


VTE Following Cesarean Section

6.2.1. For women undergoing cesarean section without additional thrombosis risk factors, we recommend against the use of thrombosis prophylaxis other than early mobilization (Grade 1B).

6.2.2. 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 (Grade 2B).

6.2.3. For women undergoing cesarean section who are considered to be at very high risk for VTE and who have multiple additional risk factors for thromboembolism that persist in the puerperium, we suggest that prophylactic LMWH be combined with elastic stockings and/or intermittent pneumatic compression over LMWH alone (Grade 2C).

6.2.4. 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 (Grade 2C).

Treatment of Proven Acute VTE During Pregnancy

7.1.1. For pregnant women with acute VTE, we recommend therapy with adjusted-dose subcutaneous LMWH over adjusted-dose UFH (Grade 1B).

7.1.2. For pregnant women with acute VTE, we recommend LMWH over vitamin K antagonist treatment antenatally (Grade 1A).

7.1.3. 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 (Grade 2C).

7.1.4. 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 (Grade 1B).

Prevention of VTE in Pregnant Women With Prior DVT or PE

8.2.1. 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 (Grade 2B).

8.2.2. 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 (Grade 2C).

8.2.3. 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 (Grade 2C).

8.2.4. 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 (Grade 2C).

Prevention of VTE in Pregnant Women With Thrombophilia and No Prior VTE

9.2.1. 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 (Grade 2B).

9.2.2. 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 S deficient, vitamin K antagonists targeted at INR 2.0 to 3.0 rather than routine care (Grade 2C).

9.2.3. 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 (Grade 2B).

9.2.4. 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 (Grade 2C).

Thrombophilia and Pregnancy Complications

10.2.1. For women with recurrent early pregnancy loss (three or more miscarriages before 10 weeks of gestation), we recommend screening for APLAs (Grade 1B).

10.2.2. For women with a history of pregnancy complications, we suggest not to screen for inherited thrombophilia (Grade 2C).

10.2.3. 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 (Grade 1B).

10.2.4. For women with inherited thrombophilia and a history of pregnancy complications, we suggest not to use antithrombotic prophylaxis (Grade 2C).

Management of Women With a History of Preeclampsia or Recurrent Fetal Loss and No Thrombophilia

11.1.1. For women considered at risk for preeclampsia, we recommend low-dose aspirin throughout pregnancy, starting from the second trimester, over no treatment (Grade 1B).

11.2.1. For women with two or more miscarriages but without APLA or thrombophilia, we recommend against antithrombotic prophylaxis (Grade 1B).

Maternal and Fetal Risks Related to Anticoagulation During Pregnancy for Mechanical Prosthetic Valves

12.1.1. For pregnant women with mechanical heart valves, we recommend one of the following anticoagulant regimens in preference to no anticoagulation (all Grade 1A):

(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.

  1. Bates SM, Greer IA, Middeldorp S, Veenstra DL, Prabulos AM, Vandvik PO; et al. (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". Chest. 141 (2 Suppl): e691S–736S. doi:10.1378/chest.11-2300. PMC 3278054. PMID 22315276.