Printer Friendly

Recommendations for thromboprophylaxis in obstetrics and gynaecology.

Venous thromboembolism (VTE) is associated with considerable morbidity, and mortality in the absence of thromboprophylaxis. Pulmonary embolism (PE) is the leading cause of maternal death worldwide. [1] Further, PE is the cause of ~20% of deaths following hysterectomy. [2] The prevalence of deep vein thrombosis (DVT) in patients having major gynaecologic surgery ranges between 15% and 40%. [3] There are a few randomised trials to guide the management of this group of patients. Recommendations in this guideline therefore reflect current best practice. Management should be individualised according to the risk-benefit ratio and cost.

Methods

On behalf of the Southern African Society of Thrombosis and Haemostasis, a representative guideline panel of professionals from various specialities reviewed the available literature on the prevention of VTE in obstetrics and gynaecology. Recommendations presented are in accordance with the more comprehensive evidence-based guidelines namely the 9th edition of the American College of Chest Physicians (ACCP), [4] the Green Top guidelines of the Royal College of Obstetricians and Gynaecologists (RCOG), [5] the American College of Obstetricians and Gynecologists (ACOG), [6] the Society of Obstetricians and Gynaecologists of Canada (SOGC), [7] Society of Obstetric Medicine of Australia and New Zealand (SOMANZ) [8] and the European Society of Regional Anaesthesia (ESRA) Guidelines on Anticoagulation and Regional Anaesthesia. [9] Many of these recommendations are formulated in the absence of strong evidence and the guidelines were also prepared in conjunction with systematic reviews and observational studies. A draft document was produced and revised by consensus agreement. The guidelines were adjudicated and co-authored by an independent international expert to avoid local bias.

VTE in gynaecology

Oestrogen and VTE risk

Oestrogen use increases the risk of VTE as a class effect which is dose dependant. [10] The risk of VTE is dependent on the route of administration. There is lower associated risk with transdermal and intra-uterine hormonal therapy as well as the progesterone-only oral contraceptive. [11,12]

Gynaecological surgery and VTE risk

Table 1 provides a practical risk assessment for VTE in patients undergoing gynaecological surgery. Patient- and procedure-related risk factors should be considered when assessing the risk of VTE.

Patient-related risk factors include: age >60 years, prior history and family history of VTE, immobility, dehydration, sepsis, underlying malignancy, pregnancy, oestrogen therapy, obesity, hereditary thrombophilia, inflammatory bowel disease, human immunodeficiency virus infection, and autoimmune diseases including antiphospholipid syndrome.

Procedure-related risk factors include: duration of the procedure; degree of tissue damage; degree of immobility following surgery; and nature of the surgical procedure. The post-operative risk of VTE in patients on the combined oral contraceptive (COC) increases from 0.5% to 1%. [13] The risk of VTE needs to be balanced against the risk of stopping the COC prior to surgery. There is insufficient evidence at this time to recommend discontinuation of the COC prior to surgery or immobilisation. Hormonal therapy does not need to be stopped prior to surgery if appropriate thromboprophylaxis is used. [5]

Thromboprophylaxis following gynaecological surgery

* Low-molecular-weight heparin (LMWH) is the anticoagulant of choice:

* Enoxaparin 40 mg subcutaneous (sc) once daily

* Dalteparin 5 000 units sc once daily

* Nadroparin 2 850 units sc once daily.

* It is recommended to use weight-adjusted LMWH dosing in patients at extremes of weight.

* It is recommended to start LMWH 6-12 hours after surgery, provided there is no active bleeding.

* In patients at high risk of bleeding or undergoing neuraxial anaesthesia, it is recommended to start LMWH a minimum of 12 hours postoperatively.

* LMWH prophylaxis should be continued until the patient is fully mobile.

* For major cancer surgery, 5 weeks of thromboprophylaxis is recommended.

* For major surgery, in patients with additional risk factors, at least 7-10 days of thromboprophylaxis is indicated.

* Avoid additional antiplatelet drugs for analgesia during anticoagulation.

* In patients at high risk of bleeding, use of mechanical prophylaxis such as intermittent pneumatic compression (IPC) should be considered. [14] There is, however, limited evidence for graduated compression stockings.

VTE in obstetrics

The risk of VTE is increased five- to tenfold in pregnancy. [15] The hypercoagulability of pregnancy persists for several weeks after delivery and the greatest risk for VTE is in the early postpartum period. [161 The recent decline in maternal deaths from VTE can be attributed to the use of thromboprophylaxis in high-risk women. [1]

There are multiple risk factors which increase the risk of VTE. Several guidelines have proposed a risk assessment score. In the absence of randomised controlled trials, there is no evidence for a complex clinical score. [17] The appropriate use of prophylaxis depends on identification of patients who are at high risk of VTE.

* Risk assessment is recommended early during pregnancy and in the postpartum period (Tables 2 and 3).

* Risk factors include previous VTE, family history of VTE, hereditary thrombophilia, antiphospholipid syndrome (APS), medical comorbidities, significant pregnancy complications, caesarean delivery (CD) prolonged antepartum immobilisation and clinical risk factors such as increased body mass index (BMI), age >35 years and parity [greater than or equal to] 3.

* High-risk patients should be managed in conjunction with a haematologist. Further, women with APS should be managed in conjunction with a haematologist and rheumatologist.

* Antepartum and postpartum thromboprophylaxis with LMWH and low-dose aspirin is recommended in women with APS and previous VTE. Higher doses of LMWH may be required. [18]

Caesarean delivery and VTE risk

Caesarean delivery (CD) is an important independent risk factor for VTE in the postpartum period. [20] The risk of VTE after an emergency CD is twice greater than after an elective CD.

* In hospital, thromboprophylaxis should be considered in all women who have undergone an elective CD. [21]

* Additional risk factors for VTE post CD include: multiple pregnancy, BMI [greater than or equal to] 30 kg/[m.sup.2], severe pre-eclampsia, re-operation, prolonged immobilisation and placenta praevia. [1]

Antepartum and postpartum thromboprophylaxis

The ideal anticoagulant in pregnancy should be one that does not cross the placenta and can be easily reversed.

* The oral direct thrombin and factor Xa inhibitors should not be used in pregnancy as the molecules are small and cross the placenta.

* Warfarin is associated with a teratogenic effect, especially between 6 and 12 weeks' gestation. In addition, there is an increased risk of miscarriage, prematurity and fetal bleeding (including intracranial haemorrhage resulting in brain damage) at any time during pregnancy.

* The preferred anticoagulant is LMWH.

* Allergic skin reactions can occur with LMWH but are uncommon. In pregnant women with severe allergic skin reactions, an alternative LMWH should be used.

* It is recommended that the platelet count be monitored one week after initiation of LMWH and at regular follow-ups thereafter.

* Fondaparinux may be considered in consultation with a haematologist. [22]

* Antepartum prophylaxis should be initiated early in pregnancy.

* Postpartum thromboprophylaxis should be continued for 6 weeks in high-risk women, for 10 days in intermediate-risk women and at least until discharge from hospital in low-risk women.

* In the presence of ongoing risk factors, e.g. prolonged hospital admission, wound infection, surgery extended thromboprophylaxis until the risk factor is no longer present should be considered.

* The use of mechanical prophylaxis, such as IPC, can be considered in patients at high risk of bleeding.

LMWH dose

* Fixed doses of LMWH, e.g. dalteparin 5 000 units daily or nadroparin 2 850 units daily or enoxaparin 40 mg daily are recommended. This is practical and covers most of the obstetric population.

* There is an increased dose requirement of LMWH during pregnancy because of increased volume of distribution and renal clearance. Therefore, regular anti-Xa monitoring is suggested.

* Dose adjustments (increase or decrease by 10 mg) to achieve a target anti-Xa level of 0.3 - 0.5 units/mL in conjunction with a haematologist is suggested.

* It is recommended to use weight-adjusted LMWH dosing with antiXa monitoring in patients at extremes of weight (Table 4). [4,5]

* Anti-Xa monitoring is also indicated in renal disease and severe pre-eclampsia. [23]

Delivery

* It is recommended that all pregnant women receiving antepartum thromboprophylaxis have a delivery plan.

* The mode of delivery is determined by the obstetric indication. A planned CD is often indicated.

* Prophylactic LMWH should be discontinued at least 12 hours prior to the expected time of epidural analgesia or delivery.

* Patients should be advised to discontinue thromboprophylaxis upon the onset of spontaneous labour.

Spinal and epidural anaesthesia

* The catheter should not be placed within 12 hours of the last dose of LMWH.

* LMWH should be started at least 6 hours after removal of the catheter. [9]

* LMWH should be delayed at least 24 hours if there is blood in the needle or neuraxial catheter during needle insertion.

* Neurological monitoring is mandatory for a minimum of 12 hours and ideally for 72 hours after neuraxial blockade.

* Extreme caution should be exercised in patients on other agents such as aspirin, clopidogrel and non-steroidal anti-inflammatories that may interfere with normal haemostasis.

Postpartum

* Assess for major bleeding postpartum (resulting in a drop in the haemoglobin concentration [greater than or equal to] 2 g/dL or bleeding requiring transfusion of at least 2 units of packed red blood cells).

* Every woman should have a repeat VTE risk assessment after delivery.

* Prophylactic LMWH may be started/restarted 6 - 12 hours post delivery or should be delayed if there is any evidence of bleeding from the surgical site.

* Warfarin, LMWH, fondaparinux and UFH are safe to use in breastfeeding mothers. The oral direct thrombin and factor Xa inhibitors should be avoided.

DOI: 10.7196/SAJOG.2018.v24i1.1312

Acknowledgements. None.

Author contributions. ES and PRD: authors; BFJ and HRB: critical review.

Funding. None.

Conflicts of interest. Prof. H R Buller reports that he has served as a scientific advisory board member for Sanofi-Aventis, Bayer HealthCare, Bristol-Myers Squibb, Daichi-Sankyo, GlaxoSmithKline, Pfizer, Roche, Isis and Thrombogenics and has received honoraria from Sanofi-Aventis, Bayer HealthCare, Bristol-Myers Squibb, Daichi-Sankyo, GlaxoSmithKline, Pfizer, Roche, Isis and Thrombogenics. Prof. BF Jacobson has received honoraria from Bayer HealthCare, Boehringer, Aspen and Sanofi-Aventis. Drs P de Jong and E Schapkaitz have declared no conflicts of interest with respect to the authorship and/or publication of this article.

[1.] Wilkinson H. Medical, Saving mothers' lives. Reviewing maternal deaths to make motherhood safer: 2006 - 2008. BJOG 2011;118(11):1402-1403. https://doi.org/10.1111/j.1471-0528.2011.03097.x

[2.] Greer IA. Epidemiology, risk factors and prophylaxis of venous thrombo-embolism in obstetrics and gynaecology. Baillieres Clin Obstet Gynaecol 1997;11(3):403-430. https://doi.org/10.1016/s0950-3552(97)80019-3

[3.] Clarke-Pearson DL, Coleman RE, Synan IS, Hinshaw, W, Creasman WT. Venous thromboembolism prophylaxis in gynecologic oncology: A prospective, controlled trial of low-dose heparin. Am J Obstet Gynecol 1983;145(5):606-613. https://doi.org/10.1016/0002-9378(83)91205-x

[4.] Bates SM, Greer IA, Middeldorp S, Veenstra DL, Prabulos AM, Vandvik PO. 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 2012;141(2 Suppl):e691S-736S.

[5.] Royal College of Obstetricians and Gynaecologists (RCOG). Green-top Guideline No. 37a: Reducing the Risk of Thrombosis and Embolism during Pregnancy and the Puerperium. London: RCOG, 2015. https://www.rcog.org.uk/en/guidelines-research-services/guidelines/gtg37a/(accessed 26 October 2017).

[6.] James A. Committee on Practice, practice bulletin no. 123: Thromboembolism in pregnancy. Obstet Gynecol 2011;118(3):718-729. https://doi.org/10.1097/aog.0b013e3182310c4c

[7.] Chan WS, Rey E, Kent NE, et al. Venous thromboembolism and antithrombotic therapy in pregnancy. J Obstet Gynaecol Can 2014;36(6):527-553. https://doi.org/10.1016/s1701-2163(15)30569-7

[8.] McLintock C, Brighton T, Chunilal S, et al. Recommendations for the diagnosis and treatment of deep venous thrombosis and pulmonary embolism in pregnancy and the postpartum period. Aust N Z J Obstet Gynaecol 2012;52U):14-22. https://doi.org/10.1111/j.1479-828x.2011.01361.x

[9.] Ducloy-Bouthors AS, Baldini A, Abdul-Kadir R, Nizard J. ESA VTE Guidelines Task Force. European guidelines on perioperative venous thromboembolism prophylaxis: Surgery during pregnancy and the immediate postpartum period. Eur J Anaesthesiol 2018;35(2):130-133. https://doi.org/10.1097/eja.0000000000000704

[10.] Stegeman BH, de Bastos M, Rosendaal FR, et al. Different combined oral contraceptives and the risk of venous thrombosis: Systematic review and network meta-analysis. BMJ 2013;347:f5298. https://doi.org/10.1136/bmj.f5298

[11.] Van Hylckama Vlieg A, Helmerhorst FM, Rosendaal FR. The risk of deep venous thrombosis associated with injectable depot-medroxyprogesterone acetate contraceptives or a levonorgestrel intrauterine device. Arterioscler Thromb Vasc Biol 2010;30(11):2297-2300. https://doi.org/10.1161/atvbaha.110.211482

[12.] Sweetland S, Beral V, Balkwill A, et al. Venous thromboembolism risk in relation to use of different types of postmenopausal hormone therapy in a large prospective study. J Thromb Haemost 2012;10(11):2277-2286. https://doi.org/10.1111/j.1538-7836.2012.04919.x

[13.] Vessey MP, Doll R, Fairbairn AS, Glober G. Postoperative thromboembolism and the use of oral contraceptives. Br Med J 1970;3(5715):123-126. https://doi.org/10.1136/bmj.3.5715.123

[14.] Ho KM, Tan JA. Stratified meta-analysis of intermittent pneumatic compression of the lower limbs to prevent venous thromboembolism in hospitalized patients. Circulation 2013;128(9):1003-1020. https://doi.org/10.1161/circulationaha.113.002690

[15.] Heit JA, Kobbervig CE, James AH, Petterson TM, Bailey KR, Melton LJ. Trends in the incidence of venous thromboembolism during pregnancy or postpartum: A 30-year population-based study. Ann Intern Med 2005;143(10):697-706. https://doi.org/10.7326/0003-4819-143-10-200511150-00006

[16.] Kamel H, Navi BB, Sriram N, Hovsepian DA, Devereux RB, Elkind MS. Risk of a thrombotic event after the 6-week postpartum period. N Engl J Med 2014;370(14):1307-1315. https://doi.org/10.1056/nejmoa1311485

[17.] Bain E, Wilson A, Tooher R, Gates S, Davies LJ, Middleton P. Prophylaxis for venous thromboembolic disease in pregnancy and the early postnatal period. Cochrane Datab Syst Rev 2014;2:CD001689. https://doi.org/10.1002/14651858.cd001689.pub3

[18.] Committee on Practice Bulletins - Obstetrics, American College of Obstetricians and Gynecologists. Practice Bulletin No. 132: Antiphospholipid syndrome. Obstet Gynecol 2012; 120(6): 1514-1521. https://doi.org/10.1097/01.aog.0000423816.39542.0f

[19.] Gerhardt A, Scharf RE, Greer IA, Zotz RB. Hereditary risk factors for thrombophilia and probability of venous thromboembolism during pregnancy and the puerperium. Blood 2016;128(19):2343-2349.

[20.] Sultan AA, Tata LJ, West, J, et al. Risk factors for first venous thromboembolism around pregnancy: A population-based cohort study from the United Kingdom. Blood 2013;121(19):3953-3961. https://doi.org/10.1182/blood-2012-11-469551

[21.] Blondon M, Casini A, Hoppe KK, Boehlen F, Righini M, Smith NL. Risks of venous thromboembolism after cesarean sections: A meta-analysis. Chest 2016;150(3):572-596. https://doi.org/10.1016/j.chest.2016.05.021

[22.] Knol HM, Schultinge L, Erwich JJ, Meijer K. Fondaparinux as an alternative anticoagulant therapy during pregnancy. J Thromb Haemost 2010;8(8):1876-1879. https://doi.org/10.1111/j.15387836.2010.03926.x

[23.] Lim W, Dentali F, Eikelboom JW, Crowther MA. Meta-analysis: Low-molecular-weight heparin and bleeding in patients with severe renal insufficiency. Ann Intern Med 2006;144(9):673-684. https://doi.org/10.7326/0003-4819-144-9-200605020-00011

Accepted date 30 April 2018.

E Schapkaitz, (1) FCPath (Haem), MMed (Haem); P R de Jong, (2) MMed, FRCOG (London), FCOG; B F Jacobson, (3) FRCS (Glasgow), PhD; H R Buller, (4) MD, PhD

(1) Department of Molecular Medicine and Haematology, National Health Laboratory Service and University of Witwatersrand, Johannesburg, South Africa

(2) Dept of Obstetrics and Gynaecology, University of Cape Town and Christiaan Barnard Memorial Hospital, Cape Town, South Africa

(3) Department of Molecular Medicine and Haematology, National Health Laboratory Service and University of Witwatersrand, Johannesburg, South Africa

(4) Department of Vascular Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands Corresponding author: E Schapkaitz (elise.schapkaitz@nhls.ac.za)
Table 1. Risk categories for gynaecological surgical patients

Risk Category                             Recommendation

High Risk
  Major surgery, age >60 years with       Thromboprophylaxis
  malignancy or history of VTE

  Major surgery, age 40 - 60 years        Thromboprophylaxis
  with malignancy

  Major surgery with additional risk      Thromboprophylaxis
  factors such as obesity
  (BMI >30 kg/[m.sup.2]), hereditary
  thrombophilia, HIV, auto-immune
  disease, oestrogen therapy

Moderate Risk
  Major surgery for benign condition      Consider thromboprophylaxis
  without other risk factors

  Minor or laparoscopic surgery with      Consider thromboprophylaxis
  additional risk factors such as
  obesity, hereditary thrombophilia,
  HIV, auto-immune disease, oestrogen
  therapy

Low Risk
  Minor or laparoscopic surgery           Early mobilisation
  without other risk factors

Table 2. Obstetric antepartum thromboprophylaxis risk assessment [4-8]

Risk Category                              Recommendation

High Risk
  Previous unprovoked or pregnancy or      Antepartum
  oestrogen-related VTE                    Thromboprophylaxis
                                           indicated
  High-risk hereditary thrombophilia
  (compound heterozygous or homozygous
  for Factor V Leiden or prothrombin
  gene

  mutation and some deficiencies of
  antithrombin) [19] and a positive
  family history of VTE *

  Anti-phospholipid syndrome and
  previous VTE

Intermediate Risk
  Single VTE related to a transient risk   Clinical monitoring
  factor (not related to pregnancy or      indicated
  oestrogen use)

  Low and intermediate risk hereditary     Consider thromboprophylaxis
  thrombophilia (some antithrombin
  deficiencies, Protein S deficiency,
  Protein C deficiency; heterozygous for
  Factor V Leiden or prothrombin gene
  mutation) [19] and a positive family
  history of VTE *

  High risk hereditary thrombophilia and
  no positive family history of VTE

  Antiphospholipid syndrome

  Non-obstetric surgery during pregnancy

  Medical co-morbidities, e.g. cancer,
  heart failure, peripartum
  cardiomyopathy, active systemic lupus
  erythematosus, inflammatory
  polyarthropathy or inflammatory bowel
  disease; nephrotic syndrome; type 1
  diabetes mellitus with nephropathy,
  sickle cell disease, current
  intravenous drug user

  Ovarian hyperstimulation syndrome
  (3 months after resolution)

Low Risk
  Age >35 years                            Early mobilisation and
                                           avoid dehydration
  BMI [greater than or equal to] 30
  kg/[m.sup.2]([dagger])                   Thromboprophylaxis if
                                           multiple ([greater than or
  Parity [greater than or equal to] 3      equal to] 4) risk factors
                                           are present
  Smoker (at least 10 cigarettes
  per day)

  Family history of unprovoked or
  oestrogen-related VTE in first-degree
  relative

  Low-risk thrombophilia

  Gross varicose veins ([double dagger])

  Current systemic infection or
  peri-operative infection

  Immobility, e.g. paraplegia,
  long-distance travel (>8 hours),
  strict bedrest [greater than or equal
  to] 7 days

  Pre-eclampsia with intrauterine growth
  restriction

  Multiple pregnancy

  In vitro fertilisation

  Dehydration/hyperemesis

* A positive family history of VTE is associated with a two- to
fourfold increase in the risk of VTE.

([dagger]) The patient's BMI is based on the booking weight.

([double dagger]) Gross varicose veins are by definition symptomatic,
above the knee or associated with phlebitis or oedema or skin changes.

Table 3. Obstetric postpartum thromboprophylaxis risk assessment [4-8]

Risk Category                           Recommendation

  High Risk                             Postpartum thromboprophylaxis
                                        indicated for at least 6 weeks
  Anyone requiring antenatal LMWH

  Previous VTE

  High-risk hereditary thrombophilia
  (compound heterozygous or
  homozygous for Factor V Leiden or
  prothrombin gene mutation or some
  deficiencies of antithrombin)

  Low- and intermediate-risk (some
  antithrombin deficiencies, Protein
  S deficiency, Protein C deficiency,
  heterozygous for Factor V Leiden or
  prothrombin gene mutation)
  hereditary thrombophilia and
  positive family history of VTE *

  Antiphospholipid syndrome

Intermediate Risk
  Caesarean delivery in labour          Postpartum thromboprophylaxis
                                        indicated for at least
  Readmission or prolonged admission    7 - 10 days
  ([greater than or equal to] 3 days)
  postpartum                            If risk factors persist or
                                        multiple ([greater than or
  Surgery in the puerperium (except     equal to] 2) risk factors are
  immediate repair of the perineum)     present, consider extending
                                        thromboprophylaxis
  Medical co-morbidities e.g. cancer,
  heart failure, peripartum
  cardiomyopathy, active systemic
  lupus erythematosus, inflammatory
  polyarthropathy or inflammatory
  bowel disease, nephrotic syndrome,
  type 1 diabetes mellitus with
  nephropathy, sickle cell disease,
  current intravenous drug user

  BMI [greater than or equal to] 40
  kg/[m.sup.2] ([dagger])

Low Risk
  Age >35 years                         Early mobilisation, mechanical
                                        prophylaxis ([section]) and
  BMI [greater than or equal to] 30     avoid dehydration
  kg/[m.sup.2]                          Postpartum thromboprophylaxis
                                        at least until discharge from
  Parity [greater than or equal to] 3   hospital if multiple
                                        ([greater than or equal to] 2)
  Smoker                                risk factors

  Elective caesarean delivery

  Family history of VTE

  Low-risk thrombophilia

  Gross varicose
  veins ([double dagger])

  Current systemic infection

  Immobility, e.g. paraplegia,
  long-distance travel (>8 hours)

  Multiple pregnancy

  Preterm delivery in this pregnancy
  (<37 weeks)

  Stillbirth in this pregnancy

  Mid-cavity or rotational operative
  delivery

  Prolonged labour (>24 hours)

  Postpartum haemorrhage
  (> 1 L or blood transfusion
  requiring re-operation)

* A positive family history of VTE is associated with a two-to
fourfold increase in the risk of VTE.

([dagger]) The patient's BMI is based on the booking weight.

([double dagger]) Gross varicose veins are by definition symptomatic,
above the knee or associated with phlebitis or oedema or skin changes.

([section]) Mechanical prophylaxis includes intermittent pneumatic
compression which is preferable to graduated compression stockings.

Table 4. Recommended dosages of LMWH
thromboprophylaxis [5]

Weight (kg)   Dosage

<50           Enoxaparin 20 mg once daily
              Dalteparin 2 500 units daily

50 - 90       Enoxaparin 40 mg once daily
              Dalteparin 5 000 units daily
              Nadroparin 2 850 units daily

91 - 130      Enoxaparin 60 mg once daily
              Dalteparin 7500 units daily

131 - 170     Enoxaparin 80 mg once daily
              Dalteparin 10 000 units daily

>170          Enoxaparin 0.6 mg/kg once daily
              Dalteparin 75 units/kg once daily

LMWH = low-molecular-weight heparin.

Table 5. Interpretation of anti-Xa levels in patients
on LMWH

Target anti-Xa levels   0.3 - 0.5 anti-Xa units/mL

Low anti-Xa level       Inadequate dosing
                        Delayed specimen draw
                        Dose of LMWH omitted
                        Weight gain
                        Gestation
                          (volume of distribution of LMWH changes)

High anti-Xa level      Excessive dosing
                        Weight loss
                        Renal dysfunction
                        Reduced creatinine clearance
                          (end of the third trimester)

Anti-Xa = anti-factor Xa; LMWH = low-molecular-weight heparin.
COPYRIGHT 2018 Health & Medical Publishing Group
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2018 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:RESEARCH
Author:Schapkaitz, E.; de Jong, P.R.; Jacobson, B.F.; Buller, H.R.
Publication:South African Journal of Obstetrics and Gynaecology
Article Type:Report
Date:Apr 1, 2018
Words:3528
Previous Article:Lactic acid as an adjuvant marker in pregnancy-associated sepsis.
Next Article:Barriers to cervical cancer screening uptake among rural women in South West Nigeria: A qualitative study.
Topics:

Terms of use | Privacy policy | Copyright © 2019 Farlex, Inc. | Feedback | For webmasters