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  • Guideline Summary
  • NGC:008692
  • 2000 Aug (revised 2011 Sep)

Thromboembolism in pregnancy.

American College of Obstetricians and Gynecologists (ACOG). Thromboembolism in pregnancy. Washington (DC): American College of Obstetricians and Gynecologists (ACOG); 2011 Sep. 12 p. (ACOG practice bulletin; no. 123).  [99 references]

This is the current release of the guideline.

This guideline updates a previous version: Thromboembolism in pregnancy. Washington (DC): American College of Obstetricians and Gynecologists (ACOG); 2000 Aug. (ACOG educational bulletin number 234).

Age Group

UMLS Concepts (what is this?)

SNOMEDCT_US
Angiography (77343006), Antenatal care (424525001), Anticardiolipin antibody measurement (65946008), Anticoagulant (372862008), Anticoagulant (81839001), Cardiolipin antibody (45396006), Cesarean section (11466000), Coagulation factor V (60208008), Computerized axial tomography (77477000), CT angiography (418272005), Deep venous thrombosis (128053003), Factor V deficiency (4320005), Factor V deficiency (88776002), Heparin (372877000), Heparin (84812008), Heparin (96382006), Induction of labor (236958009), Intermittent pneumatic compression device (432441000124100), Low molecular weight heparin (373294004), Low molecular weight heparin (87233003), Lupus anticoagulant (16923002), Postpartum care (133906008), Pregnancy (289908002), Pulmonary embolism (59282003), Risk assessment (225338004), Risk factor (80943009), Thromboembolic disorder (13713005), Thromboembolic disorder (371039008), Thrombolytic therapy (426347000), Thrombophilia (234467004), Thrombophilia (76612001), Ultrasonography (16310003), Ultrasonography (278292003), Ultrasonography (359659005), Venous thrombosis (111293003), Warfarin (372756006), Warfarin (48603004)

Major Recommendations

The grades of evidence (I-III) and levels of recommendations (A-C) are defined at the end of the "Major Recommendations"

The following recommendation is based on good and consistent scientific evidence (Level A):

  • When signs or symptoms suggest new onset deep vein thrombosis (DVT), the recommended initial diagnostic test is compression ultrasonography of the proximal veins.

The following recommendations and conclusions are based on limited or inconsistent scientific evidence (Level B):

  • The preferred anticoagulants in pregnancy are heparin compounds.
  • A reasonable approach to minimize postpartum bleeding complications is resumption of anticoagulation therapy no sooner than 4–6 hours after vaginal delivery or 6–12 hours after cesarean delivery.
  • Because warfarin, low-molecular-weight heparin (LMWH), and unfractionated heparin do not accumulate in breast milk and do not induce an anticoagulant effect in the infant, these anticoagulants are compatible with breastfeeding.

The following recommendations are based primarily on consensus and expert opinion (Level C):

  • Women with a history of thrombosis who have not had a complete evaluation of possible underlying etiologies should be tested for both antiphospholipid antibodies and for inherited thrombophilias.
  • Therapeutic anticoagulation is recommended for women with acute thromboembolism during the current pregnancy or those at high risk of venous thromboembolism, such as women with mechanical heart valves.
  • When reinstitution of anticoagulation therapy is planned postpartum, pneumatic compression devices should be left in place until the patient is ambulatory and until anticoagulation therapy is restarted.
  • Women receiving either therapeutic or prophylactic anticoagulation may be converted from LMWH to the shorter half-life unfractionated heparin in the last month of pregnancy or sooner if delivery appears imminent.
  • It is recommended to withhold neuraxial blockade for 10–12 hours after the last prophylactic dose of LMWH or 24 hours after the last therapeutic dose of LMWH.
  • Placement of pneumatic compression devices before cesarean delivery is recommended for all women not already receiving thromboprophylaxis.

Definitions:

Grades of Evidence

I: Evidence obtained from at least one properly designed randomized controlled trial.

II-1: Evidence obtained from well-designed controlled trials without randomization.

II-2: Evidence obtained from well-designed cohort or case-control analytic studies, preferably from more than one center or research group.

II-3: Evidence obtained from multiple time series with or without the intervention. Dramatic results in uncontrolled experiments also could be regarded as this type of evidence.

III: Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.

Levels of Recommendations

Level A—Recommendations are based on good and consistent scientific evidence.

Level B—Recommendations are based on limited or inconsistent scientific evidence.

Level C—Recommendations are based primarily on consensus and expert opinion.

Clinical Algorithm(s)

An algorithm for diagnosis of deep vein thrombosis during pregnancy is provided in the original guideline document.

Disease/Condition(s)

Venous thromboembolism during pregnancy

  • Deep vein thrombosis (DVT)
  • Pulmonary embolism (PE)

Guideline Category

Diagnosis

Management

Prevention

Risk Assessment

Treatment

Clinical Specialty

Cardiology

Emergency Medicine

Family Practice

Hematology

Internal Medicine

Obstetrics and Gynecology

Pulmonary Medicine

Intended Users

Advanced Practice Nurses

Physician Assistants

Physicians

Guideline Objective(s)

To provide information regarding the risk factors, diagnosis, management, and prevention of thromboembolism, particularly venous thromboembolism in pregnancy

Target Population

Pregnant women at risk of venous thromboembolism

Interventions and Practices Considered

Diagnosis/Risk Assessment

  1. Evaluation of risk factors for thromboembolism
  2. Testing for both antiphospholipid antibodies and for inherited thrombophilias in women with a history of thrombosis
  3. Compression ultrasonography for suspected deep vein thrombosis
  4. Ventilation–perfusion scanning and computed tomographic (CT) angiography for suspected pulmonary embolism

Treatment/Management/Prevention

  1. Therapeutic or prophylactic anticoagulation with unfractionated heparin or low-molecular-weight heparin (LMWH)
  2. Restricted use of warfarin in pregnancy
  3. Placement of pneumatic compression devices before cesarean delivery for women not already receiving thromboprophylaxis
  4. Cessation of anticoagulant therapy and induction of labor
  5. Conversion from LMWH to unfractionated heparin during last month of pregnancy
  6. Resumption of anticoagulant therapy postpartum

Major Outcomes Considered

  • Risk of thromboembolism during pregnancy
  • Effectiveness of anticoagulants for preventing and treating venous thromboembolism
  • Anticoagulant-related maternal and neonatal morbidity and mortality

Methods Used to Collect/Select the Evidence

Hand-searches of Published Literature (Primary Sources)

Hand-searches of Published Literature (Secondary Sources)

Searches of Electronic Databases

Description of Methods Used to Collect/Select the Evidence

The MEDLINE database, the Cochrane Library, and the American College of Obstetricians and Gynecologists' own internal resources and documents were used to conduct a literature search to locate relevant articles published between January 1985 and December 2010. The search was restricted to articles published in the English language. Priority was given to articles reporting results of original research, although review articles and commentaries also were consulted. Abstracts of research presented at symposia and scientific conferences were not considered adequate for inclusion in this document.

Guidelines published by organizations or institutions such as the National Institutes of Health and the American College of Obstetricians and Gynecologists were reviewed, and additional studies were located by reviewing bibliographies of identified articles. When reliable research was not available, expert opinions from obstetrician–gynecologists were used.

Number of Source Documents

Not stated

Methods Used to Assess the Quality and Strength of the Evidence

Weighting According to a Rating Scheme (Scheme Given)

Rating Scheme for the Strength of the Evidence

Studies were reviewed and evaluated for quality according to the method outlined by the U.S. Preventive Services Task Force.

I: Evidence obtained from at least one properly designed randomized controlled trial.

II-1: Evidence obtained from well-designed controlled trials without randomization.

II-2: Evidence obtained from well-designed cohort or case-control analytic studies, preferably from more than one center or research group.

II-3: Evidence obtained from multiple time series with or without the intervention. Dramatic results in uncontrolled experiments also could be regarded as this type of evidence.

III: Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.

Methods Used to Analyze the Evidence

Systematic Review

Description of the Methods Used to Analyze the Evidence

Not stated

Methods Used to Formulate the Recommendations

Expert Consensus

Description of Methods Used to Formulate the Recommendations

Analysis of available evidence was given priority in formulating recommendations. When reliable research was not available, expert opinions from obstetrician-gynecologists were used. See also the "Rating Scheme for the Strength of Recommendations" field regarding Level C recommendations.

Rating Scheme for the Strength of the Recommendations

Based on the highest level of evidence found in the data, recommendations are provided and graded according to the following categories:

Level A—Recommendations are based on good and consistent scientific evidence.

Level B—Recommendations are based on limited or inconsistent scientific evidence.

Level C—Recommendations are based primarily on consensus and expert opinion.

Cost Analysis

The guideline developer reviewed a published cost analysis.

Method of Guideline Validation

Internal Peer Review

Description of Method of Guideline Validation

Practice Bulletins are validated by two internal clinical review panels composed of practicing obstetrician-gynecologists generalists and sub-specialists. The final guidelines are also reviewed and approved by the American College of Obstetricians and Gynecologists (ACOG) Executive Board.

Type of Evidence Supporting the Recommendations

The type of supporting evidence is identified and graded for each recommendation (see the "Major Recommendations" field).

Potential Benefits

  • Appropriate use of anticoagulant therapy to prevent venous thromboembolism in pregnant women
  • Improved maternal and fetal-neonatal outcome

Potential Harms

  • Bleeding complications can arise from administration of unfractionated heparin or low-molecular-weight heparin (LMWH), and this complication should be considered before initiating anticoagulation therapy.
  • In nonpregnant patients, LMWH has been associated with fewer adverse effects than unfractionated heparin. Potential advantages of LMWH include fewer bleeding episodes, a more predictable therapeutic response, a lower risk of heparin-induced thrombocytopenia, a longer half-life, and less bone mineral density loss. Unfractionated heparin, which is associated with increased bruising at the injection sites, also has been associated with other skin reactions and serious allergic reactions. Moreover, unfractionated heparin is dispensed in multiple-dose vials, which are potentially vulnerable to contamination. Besides its greater cost, a relative disadvantage of LMWH at the time of delivery is its longer half-life, which is an important consideration for both neuraxial anesthesia and peripartum bleeding risk.
  • Warfarin, a common agent for long-term anticoagulation therapy outside of pregnancy, has been associated with potentially harmful fetal effects, especially with first-trimester exposure. Warfarin embryopathy has been linked with exposure at 6–12 weeks of gestation, highlighting the importance of early pregnancy care in such patients.
  • Both ventilation–perfusion scanning and computed tomographic (CT) angiography are associated with relatively low radiation exposure for the fetus. The concerns about maternal breast radiation exposure with CT angiography must be weighed against the potential consequences of withholding appropriate imaging and failing to make a proper diagnosis of pulmonary embolism.

Qualifying Statements

The information in this guideline is designed to aid practitioners in making decisions about appropriate obstetric and gynecologic care. These guidelines should not be construed as dictating an exclusive course of treatment or procedure. Variations in practice may be warranted based on the needs of the individual patient, resources, and limitations unique to the institution or type of practice.

Description of Implementation Strategy

An implementation strategy was not provided.

Implementation Tools

Audit Criteria/Indicators

Clinical Algorithm

Patient Resources

For information about availability, see the Availability of Companion Documents and Patient Resources fields below.

IOM Care Need

Getting Better

Staying Healthy

IOM Domain

Effectiveness

Bibliographic Source(s)

American College of Obstetricians and Gynecologists (ACOG). Thromboembolism in pregnancy. Washington (DC): American College of Obstetricians and Gynecologists (ACOG); 2011 Sep. 12 p. (ACOG practice bulletin; no. 123).  [99 references]

Adaptation

Not applicable: The guideline was not adapted from another source.

Date Released

2000 Aug (revised 2011 Sep)

Guideline Developer(s)

American College of Obstetricians and Gynecologists - Medical Specialty Society

Source(s) of Funding

American College of Obstetricians and Gynecologists (ACOG)

Guideline Committee

American College of Obstetricians and Gynecologists (ACOG) Committee on Practice Bulletins—Obstetrics

Composition of Group That Authored the Guideline

This Practice Bulletin was developed by the Committee on Practice Bulletins—Obstetrics with the assistance of Andra James, MD.

American College of Obstetricians and Gynecologists (ACOG) committees are created or abolished and their overall function defined by the Executive Board. Appointments are made for one year, with the understanding that such appointment may be continued for a total of three years. The majority of committee members are Fellows, but Junior Fellows also are eligible for appointment. Some committees may have representatives from other organizations when this is particularly appropriate to committee activities. The president elect appoints committee members annually.

Financial Disclosures/Conflicts of Interest

Not stated

Guideline Status

This is the current release of the guideline.

This guideline updates a previous version: Thromboembolism in pregnancy. Washington (DC): American College of Obstetricians and Gynecologists (ACOG); 2000 Aug. (ACOG educational bulletin number 234).

Guideline Availability

Electronic copies: None available

Print copies: Available for purchase from the American College of Obstetricians and Gynecologists (ACOG) Distribution Center, PO Box 933104, Atlanta, GA 31193-3104; telephone, 800-762-2264; e-mail: sales@acog.org. The ACOG Bookstore is available online at the ACOG Web site External Web Site Policy.

Availability of Companion Documents

A proposed performance measure is included in the original guideline document.

Patient Resources

The following is available:

Print copies: Available for purchase from the American College of Obstetricians and Gynecologists (ACOG) Distribution Center, PO Box 4500, Kearneysville, WV 25430-4500; telephone, 800-762-2264, ext. 192; e-mail: sales@acog.org. The ACOG Bookstore is available online at the ACOG Web site External Web Site Policy.

Please note: This patient information is intended to provide health professionals with information to share with their patients to help them better understand their health and their diagnosed disorders. By providing access to this patient information, it is not the intention of NGC to provide specific medical advice for particular patients. Rather we urge patients and their representatives to review this material and then to consult with a licensed health professional for evaluation of treatment options suitable for them as well as for diagnosis and answers to their personal medical questions. This patient information has been derived and prepared from a guideline for health care professionals included on NGC by the authors or publishers of that original guideline. The patient information is not reviewed by NGC to establish whether or not it accurately reflects the original guideline's content.

NGC Status

This NGC summary was completed by ECRI on September 14, 2004. The information was verified by the guideline developer on December 8, 2004. This summary was updated by ECRI on March 6, 2007 following the U.S. Food and Drug Administration (FDA) advisory on Coumadin (warfarin sodium). This summary was updated by ECRI Institute on June 22, 2007 following the U.S. Food and Drug Administration (FDA) advisory on heparin sodium injection. This summary was updated by ECRI Institute on September 7, 2007 following the revised U.S. Food and Drug Administration (FDA) advisory on Coumadin (warfarin). This NGC summary was updated by ECRI Institute on October 21, 2011. This summary was updated by ECRI Institute on March 10, 2014 following the U.S. Food and Drug Administration advisory on Low Molecular Weight Heparins.

Copyright Statement

This NGC summary is based on the original guideline, which is subject to the guideline developer's copyright restrictions.

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