Skip to main content
PMC home page
Medline Book to support NIHPA logoLink to Medline Book to support NIHPA
. 2024 Mar;28(9):1–176. doi: 10.3310/DFWT3873

Thromboprophylaxis during pregnancy and the puerperium: a systematic review and economic evaluation to estimate the value of future research.

Sarah Davis, Abdullah Pandor, Fiona C Sampson, Jean Hamilton, Catherine Nelson-Piercy, Beverley J Hunt, Jahnavi Daru, Steve Goodacre, Rosie Carser, Gill Rooney, Mark Clowes
PMCID: PMC11017156  PMID: 38476084

Abstract

BACKGROUND

Pharmacological prophylaxis to prevent venous thromboembolism is currently recommended for women assessed as being at high risk of venous thromboembolism during pregnancy or in the 6 weeks after delivery (the puerperium). The decision to provide thromboprophylaxis involves weighing the benefits, harms and costs, which vary according to the individual's venous thromboembolism risk. It is unclear whether the United Kingdom's current risk stratification approach could be improved by further research.

OBJECTIVES

To quantify the current decision uncertainty associated with selecting women who are pregnant or in the puerperium for thromboprophylaxis and to estimate the value of one or more potential future studies that would reduce that uncertainty, while being feasible and acceptable to patients and clinicians.

METHODS

A decision-analytic model was developed which was informed by a systematic review of risk assessment models to predict venous thromboembolism in women who are pregnant or in the puerperium. Expected value of perfect information analysis was used to determine which factors are associated with high decision uncertainty and should be the target of future research. To find out whether future studies would be acceptable and feasible, we held workshops with women who have experienced a blood clot or have been offered blood-thinning drugs and surveyed healthcare professionals. Expected value of sample information analysis was used to estimate the value of potential future research studies.

RESULTS

The systematic review included 17 studies, comprising 19 unique externally validated risk assessment models and 1 internally validated model. Estimates of sensitivity and specificity were highly variable ranging from 0% to 100% and 5% to 100%, respectively. Most studies had unclear or high risk of bias and applicability concerns. The decision analysis found that there is substantial decision uncertainty regarding the use of risk assessment models to select high-risk women for antepartum prophylaxis and obese postpartum women for postpartum prophylaxis. The main source of decision uncertainty was uncertainty around the effectiveness of thromboprophylaxis for preventing venous thromboembolism in women who are pregnant or in the puerperium. We found that a randomised controlled trial of thromboprophylaxis in obese postpartum women is likely to have substantial value and is more likely to be acceptable and feasible than a trial recruiting women who have had a previous venous thromboembolism. In unselected postpartum women and women following caesarean section, the poor performance of risk assessment models meant that offering prophylaxis based on these models had less favourable cost effectiveness with lower decision uncertainty.

LIMITATIONS

The performance of the risk assessment model for obese postpartum women has not been externally validated.

CONCLUSIONS

Future research should focus on estimating the efficacy of pharmacological thromboprophylaxis in pregnancy and the puerperium, and clinical trials would be more acceptable in women who have not had a previous venous thromboembolism.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42020221094.

FUNDING

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR131021) and is published in full in Health Technology Assessment; Vol. 28, No. 9. See the NIHR Funding and Awards website for further award information.

Plain language summary

Women who are pregnant or who have given birth in the previous 6 weeks are at increased risk of developing blood clots that can cause serious illness or death. Small doses of blood thinners given by injection are safe in pregnancy and can reduce the risk of blood clots, but they can slightly increase the risk of bleeding. Healthcare professionals use risk assessment tools to decide if a woman is at high risk of blood clots and should be offered blood thinners. We wanted to find out what research would be useful to help them make better decisions. We reviewed previous research to establish which risk assessment tools are best at predicting who will have a blood clot. We then created a mathematical model to predict what would happen when using different risk assessment tools to decide who should be offered blood thinners, both during pregnancy and after giving birth. We found that there was a lot of uncertainty about which women should be offered blood thinners. This was mainly because there have only been a few small studies comparing blood thinners to no treatment in pregnant women or women who have recently given birth. We estimated the value of future studies comparing blood thinners to no treatment, in groups of women with different risk factors, by predicting what information we would gain and how this would be used to improve decisions about using blood thinners. To find out whether these studies would be acceptable and feasible, we held workshops with women who have experienced a blood clot or have been offered blood thinners and surveyed healthcare professionals. We found that a study in obese women who have recently given birth would have substantial value and may be more acceptable than a study in pregnant women with a previous blood clot.

Full text of this article can be found in Bookshelf.

References

  1. Knight M, Bunch K, Tuffnel D, Patel R, Shakespeare J, Kotnis R, et al. Saving Lives, Improving Mother’s Care: Lessons Learned to Inform Maternity Care from the UK and Ireland Confidential Enquiries into Maternal Deaths and Morbidity 2017–19. Oxford: National Perinatal Epidemiology Unity, University of Oxford; 2021.
  2. Heit JA, Kobbervig CE, James AH, Petterson TM, Bailey KR, Melton LJ 3rd. Trends in the incidence of venous thromboembolism during pregnancy or postpartum: a 30-year population-based study. Ann Intern Med 2005;143:697–706. https://doi.org/10.7326/0003-4819-143-10-200511150-00006 doi: 10.7326/0003-4819-143-10-200511150-00006. [DOI] [PubMed]
  3. James AH, Jamison MG, Brancazio LR, Myers ER. Venous thromboembolism during pregnancy and the postpartum period: incidence, risk factors, and mortality. Am J Obstet Gynecol 2006;194:1311–5. https://doi.org/10.1016/j.ajog.2005.11.008 doi: 10.1016/j.ajog.2005.11.008. [DOI] [PubMed]
  4. Lindqvist P, Dahlbäck B, Marŝál K. Thrombotic risk during pregnancy: a population study. Obstet Gynecol 1999;94:595–9. https://doi.org/10.1016/S0029-7844(99)00308-7 doi: 10.1016/s0029-7844(99)00308-7. [DOI] [PubMed]
  5. Meng K, Hu X, Peng X, Zhang Z. Incidence of venous thromboembolism during pregnancy and the puerperium: a systematic review and meta-analysis. J Matern Fetal Neonatal Med 2015;28:245–53. https://doi.org/10.3109/14767058.2014.913130 doi: 10.3109/14767058.2014.913130. [DOI] [PubMed]
  6. National Institute for Health and Care Excellence (NICE). Venous Thromboembolism in Over 16s: Reducing the Risk of Hospital-acquired Deep Vein Thrombosis or Pulmonary Embolism – NICE Guideline 89. London: NICE; 2019. URL: www.nice.org.uk/guidance/ng89/evidence (accessed 20 February 2022). [PubMed]
  7. Royal College of Obstetricians & Gynaecologists. Thrombosis and Embolism during Pregnancy and the Puerperium, Reducing the Risk (Green-top Guideline No. 37a). London: Royal College of Obstetricians & Gynaecologists; 2015.
  8. Middleton P, Shepherd E, Gomersall JC. Venous thromboembolism prophylaxis for women at risk during pregnancy and the early postnatal period. Cochrane Database Syst Rev 2021;3:CD001689. https://doi.org/10.1002/14651858.CD001689.pub4 doi: 10.1002/14651858.CD001689.pub4. [DOI] [PMC free article] [PubMed]
  9. Zheng J, Chen Q, Fu J, Lu Y, Han T, He P. Critical appraisal of international guidelines for the prevention and treatment of pregnancy-associated venous thromboembolism: a systematic review. BMC Cardiovasc Disord 2019;19:199. https://doi.org/10.1186/s12872-019-1183-3 doi: 10.1186/s12872-019-1183-3. [DOI] [PMC free article] [PubMed]
  10. Kotaska A. Postpartum venous thromboembolism prophylaxis may cause more harm than benefit: a critical analysis of international guidelines through an evidence-based lens. BJOG 2018;125:1109–16. https://doi.org/10.1111/1471-0528.15150 doi: 10.1111/1471-0528.15150. [DOI] [PMC free article] [PubMed]
  11. Sultan AA, West J, Grainge MJ, Riley RD, Tata LJ, Stephansson O, et al. Development and validation of risk prediction model for venous thromboembolism in postpartum women: multinational cohort study. BMJ 2016;355:i6253. https://doi.org/10.1136/bmj.i6253 doi: 10.1136/bmj.i6253. [DOI] [PMC free article] [PubMed]
  12. Palmerola KL, D’Alton ME, Brock CO, Friedman AM. A comparison of recommendations for pharmacologic thromboembolism prophylaxis after caesarean delivery from three major guidelines. BJOG 2016;123:2157–62. https://doi.org/10.1111/1471-0528.13706 doi: 10.1111/1471-0528.13706. [DOI] [PubMed]
  13. Shacaluga A, Rayment R. Venous thromboembolic risk assessment in pregnancy: comparison of the All-Wales maternity risk assessment tool with guidance from the Royal College of Obstetrics and Gynaecology. Br J Haematol 2019;185:162–5. https://doi.org/10.1111/bjh.15417 doi: 10.1111/bjh.15417. [DOI] [PubMed]
  14. Revell BJ, Smith RP. Thrombosis and embolism in pregnancy and the puerperium, reducing the risk: what proportion of patients reach the threshold for thromboprophylaxis? Obstet Med 2011;4:12–4. https://doi.org/10.1258/om.2010.100042 doi: 10.1258/om.2010.100042. [DOI] [PMC free article] [PubMed]
  15. O’Shaughnessy F, Donnelly JC, Bennett K, Damkier P, Ainle FN, Cleary BJ. Prevalence of postpartum venous thromboembolism risk factors in an Irish urban obstetric population. J Thromb Haemost 2019;17:1875–85. https://doi.org/10.1111/jth.14568 doi: 10.1111/jth.14568. [DOI] [PubMed]
  16. Claxton K, Ginnelly L, Sculpher M, Philips Z, Palmer S. A pilot study on the use of decision theory and value of information analysis as part of the NHS Health Technology Assessment programme. Health Technol Assess 2004;8:1–103, iii. https://doi.org/10.3310/hta8310 doi: 10.3310/hta8310. [DOI] [PubMed]
  17. Ades AE, Lu G, Claxton K. Expected value of sample information calculations in medical decision modeling. Med Decis Making 2004;24:207–27. https://doi.org/10.1177/0272989X04263162 doi: 10.1177/0272989X04263162. [DOI] [PubMed]
  18. Rodger MA, Phillips P, Kahn SR, James AH, Konkle BA; PROSPER Investigators Low-molecular-weight heparin to prevent postpartum venous thromboembolism. A pilot randomised placebo-controlled trial. Thromb Haemost 2015;113:212–6. https://doi.org/10.1160/TH14-06-0485 doi: 10.1160/TH14-06-0485. [DOI] [PubMed]
  19. Rodger MA, Phillips P, Kahn SR, Bates S, McDonald S, Khurana R, et al.; PROSPER Investigators: Tim Ramsay, Dean Fergusson, Anne McLeod, Wee Shian Chan, Rshmi Khurana, Kara Narenberg, Haim Abenhaim, John Heit, Ghada Bourjeilly, Paul Gibson, Kent Bailey. Low molecular weight heparin to prevent postpartum venous thromboembolism: a pilot study to assess the feasibility of a randomized, open-label trial. Thromb Res 2016;142:17–20. https://doi.org/10.1016/j.thromres.2016.04.004
  20. Moher D, Liberati A, Tetzlaff J, Altman DG, PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. Ann Intern Med 2009;151:264–9. https://doi.org/10.7326/0003-4819-151-4-200908180-00135 doi: 10.7326/0003-4819-151-4-200908180-00135. [DOI] [PubMed]
  21. Wilczynski N. McMaster University – HiRU’s Approach to Search Filter Development. Ontario, Canada: Health Information Research Unit. URL: https://hiru.mcmaster.ca/hiru/HIRU_Hedges_home.aspx (accessed 23 November 2020).
  22. Moons KGM, Wolff RF, Riley RD, Whiting PF, Westwood M, Collins GS, et al. PROBAST: a tool to assess risk of bias and applicability of prediction model studies: explanation and elaboration. Ann Intern Med 2019;170:W1–33. https://doi.org/10.7326/M18-1377 doi: 10.7326/M18-1377. [DOI] [PubMed]
  23. Wolff RF, Moons KGM, Riley RD, Whiting PF, Westwood M, Collins GS, et al.; PROBAST Group†. PROBAST: a tool to assess the risk of bias and applicability of prediction model studies. Ann Intern Med 2019;170:51–8. https://doi.org/10.7326/M18-1376 doi: 10.7326/M18-1376. [DOI] [PubMed]
  24. Centre for Reviews and Dissemination. Systematic Reviews: CRD’s Guidance for Undertaking Reviews in Health Care. York: Centre for Reviews and Dissemination; 2009.
  25. McKenzie JE, Brennan SE, Ryan RE, Thomson HJ, Johnston RV. Summarizing study characteristics and preparing for synthesis. In: Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, et al., editors. Cochrane Handbook for Systematic Reviews of Interventions Version 6.2 (updated February 2021). London: Cochrane; 2021.
  26. Hosmer DW, Lemeshow S. Applied Logistic Regression. 2nd edn. New York: John Wiley & Sons; 2000.
  27. Bauersachs RM, Dudenhausen J, Faridi A, Fischer T, Fung S, Geisen U, et al.; EThIG Investigators. Risk stratification and heparin prophylaxis to prevent venous thromboembolism in pregnant women. Thromb Haemost 2007;98:1237–45. https://doi.org/10.1160/th07-05-0329 doi: 10.1160/th07-05-0329. [DOI] [PubMed]
  28. Binstock AB, Larkin JC. Development of a venous thromboembolism prevention tool in the postpartum period. Obstet Gynecol 2019;133:52S. https://doi.org/10.1097/01.AOG.0000558997.74246.16
  29. Cavazza S, Rainaldi MP, Adduci A, Palareti G. Thromboprophylaxis following cesarean delivery: one site prospective pilot study to evaluate the application of a risk score model. Thromb Res 2012;129:28–31. https://doi.org/10.1016/j.thromres.2011.06.028 doi: 10.1016/j.thromres.2011.06.028. [DOI] [PubMed]
  30. Chau C, Campagna J, Vial M, Rambeaud C, Loundou A, Bretelle F. Use of a personalized iterative score to evaluate risk of venous thromboembolism during pregnancy and puerperium. Int J Gynaecol Obstet 2019;144:277–82. https://doi.org/10.1002/ijgo.12754 doi: 10.1002/ijgo.12754. [DOI] [PubMed]
  31. Chauleur C, Quenet S, Varlet MN, Seffert P, Laporte S, Decousus H, Mismetti P. Feasibility of an easy-to-use risk score in the prevention of venous thromboembolism and placental vascular complications in pregnant women: a prospective cohort of 2736 women. Thromb Res 2008;122:478–84. https://doi.org/10.1016/j.thromres.2007.12.020 doi: 10.1016/j.thromres.2007.12.020. [DOI] [PubMed]
  32. Dargaud Y, Rugeri L, Fleury C, Battie C, Gaucherand P, Huissoud C, et al. Personalized thromboprophylaxis using a risk score for the management of pregnancies with high risk of thrombosis: a prospective clinical study. J Thromb Haemos JTH 2017;15:897–906. https://doi.org/10.1111/jth.13660 doi: 10.1111/jth.13660. [DOI] [PubMed]
  33. Dargaud Y, Rugeri L, Ninet J, Negrier C, Trzeciak MC. Management of pregnant women with increased risk of venous thrombosis. Int J Gynaecol Obstet 2005;90:203–7. https://doi.org/10.1016/j.ijgo.2005.05.003 doi: 10.1016/j.ijgo.2005.05.003. [DOI] [PubMed]
  34. Gassmann N, Viviano M, Righini M, Fontana P, Martinez de Tejada B, Blondon M. Estimating the risk thresholds used by guidelines to recommend postpartum thromboprophylaxis. J Thromb Haemos 2020;19:452–9. https://doi.org/10.1111/jth.15166 doi: 10.1111/jth.15166. [DOI] [PubMed]
  35. Hase EA, de Barros VIPVL, Igai AMK, Francisco RPV, Zugaib M. Risk assessment of venous thromboembolism and thromboprophylaxis in pregnant women hospitalized with cancer: preliminary results from a risk score. Clinics (Sao Paulo) 2018;73:e368. https://doi.org/10.6061/clinics/2018/e368 doi: 10.6061/clinics/2018/e368. [DOI] [PMC free article] [PubMed]
  36. Lindqvist PG, Torsson J, Almqvist A, Bjorgell O. Postpartum thromboembolism: severe events might be preventable using a new risk score model. Vasc Health Risk Manag 2008;4:1081–7. https://doi.org/10.2147/vhrm.s2831 doi: 10.2147/vhrm.s2831. [DOI] [PMC free article] [PubMed]
  37. Lok WY, Kong CW, To WWK. A local risk score model for venous thromboembolism prophylaxis for caesarean section in Chinese women and comparison with international guidelines. Taiwan J Obstet Gynecol 2019;58:520–5. https://doi.org/10.1016/j.tjog.2019.05.016 doi: 10.1016/j.tjog.2019.05.016. [DOI] [PubMed]
  38. Testa S, Passamonti SM, Paoletti O, Bucciarelli P, Ronca E, Riccardi A, et al. The ‘Pregnancy Health-care Program’ for the prevention of venous thromboembolism in pregnancy. Intern Emerg Med 2015;10:129–34. https://doi.org/10.1007/s11739-014-1111-6 doi: 10.1007/s11739-014-1111-6. [DOI] [PubMed]
  39. Tran JP, Stribling SS, Ibezim UC, Omere C, McEnery KA, Pacheco LD, et al. Performance of risk assessment models for peripartum thromboprophylaxis. Reprod Sci 2019;26:1243–8. https://doi.org/10.1177/1933719118813197 doi: 10.1177/1933719118813197. [DOI] [PubMed]
  40. Weiss N, Bernstein PS. Risk factor scoring for predicting venous thromboembolism in obstetric patients. Am J Obstet Gynecol 2000;182:1073–5. https://doi.org/10.1067/mob.2000.105441 doi: 10.1067/mob.2000.105441. [DOI] [PubMed]
  41. Ellis-Kahana J, Sparks AD, Gimovsky AC, James AH, Ahmadzia HK. Developing a model for predicting venous thromboembolism in obese pregnant women in a national study. Thromb Res 2020;191:42–9. https://doi.org/10.1016/j.thromres.2020.03.025 doi: 10.1016/j.thromres.2020.03.025. [DOI] [PMC free article] [PubMed]
  42. Collins GS, Reitsma JB, Altman DG, Moons KG. Transparent reporting of a multivariable prediction model for individual prognosis or diagnosis (TRIPOD): the TRIPOD statement. BMC Med 2015;13:1. https://doi.org/10.1186/s12916-014-0241-z doi: 10.1186/s12916-014-0241-z. [DOI] [PMC free article] [PubMed]
  43. Moons KG, de Groot JA, Bouwmeester W, Vergouwe Y, Mallett S, Altman DG, et al. Critical appraisal and data extraction for systematic reviews of prediction modelling studies: the CHARMS checklist. PLOS Med 2014;11:e1001744. https://doi.org/10.1371/journal.pmed.1001744 doi: 10.1371/journal.pmed.1001744. [DOI] [PMC free article] [PubMed]
  44. National Institute for Health and Care Excellence (NICE). Guide to the Methods of Technology Appraisal. London: National Institute for Health and Care Excellence; 2013. URL: www.nice.org.uk/process/pmg9/chapter/foreword (accessed 23 November 2020).
  45. Curtis L, Burns A. Unit Costs of Health and Social Care. Canterbury: University of Kent; 2020. https://doi.org/10.22024/UniKent/01.02.84818
  46. Pandor A, Horner D, Davis S, Goodacre S, Stevens JW, Clowes M, et al. Different strategies for pharmacological thromboprophylaxis for lower-limb immobilisation after injury: systematic review and economic evaluation. Health Technol Assess 2019;23:1–190. https://doi.org/10.3310/hta23630 doi: 10.3310/hta23630. [DOI] [PMC free article] [PubMed]
  47. Horner D, Davis S, Pandor A, Shulver H, Goodacre S, Hind D, et al. An evidence synthesis and economic evaluation of venous thromboembolism risk assessment models for hospital inpatients: the VTEAM project. Health Technol Assess 2021; in press. doi: 10.3310/AWTW6200. [DOI] [PMC free article] [PubMed]
  48. Tardy B, Chalayer E, Kamphuisen PW, Ni Ainle F, Verhamme P, Varlet MN, et al.; SSC Subcommittee on Control of Anticoagulation of the ISTH. Definition of bleeding events in studies evaluating prophylactic antithrombotic therapy in pregnant women: a systematic review and a proposal from the ISTH SSC. J Thromb Haemost 2019;17:1979–88. https://doi.org/10.1111/jth.14576 doi: 10.1111/jth.14576. [DOI] [PubMed]
  49. Greer IA, Nelson-Piercy C. Low-molecular-weight heparins for thromboprophylaxis and treatment of venous thromboembolism in pregnancy: a systematic review of safety and efficacy. Blood 2005;106:401–7. https://doi.org/10.1182/blood-2005-02-0626 doi: 10.1182/blood-2005-02-0626. [DOI] [PubMed]
  50. Galambosi P, Hiilesmaa V, Ulander VM, Laitinen L, Tiitinen A, Kaaja R. Prolonged low-molecular-weight heparin use during pregnancy and subsequent bone mineral density. Thromb Res 2016;143:122–6. https://doi.org/10.1016/j.thromres.2016.05.016 doi: 10.1016/j.thromres.2016.05.016. [DOI] [PubMed]
  51. Moody A. Health Survey for England 2019 Overweight and Obesity in Adults and Children. Leeds: NHS Digital; 2020. URL: https://files.digital.nhs.uk/9D/4195D5/HSE19-Overweight-obesity-rep.pdf (accessed 15 April 2021).
  52. De Stefano V, Martinelli I, Rossi E, Battaglioli T, Za T, Mannuccio Mannucci P, Leone G. The risk of recurrent venous thromboembolism in pregnancy and puerperium without antithrombotic prophylaxis. Br J Haematol 2006;135:386–91. https://doi.org/10.1111/j.1365-2141.2006.06317.x doi: 10.1111/j.1365-2141.2006.06317.x. [DOI] [PubMed]
  53. Pabinger I, Grafenhofer H, Kaider A, Kyrle PA, Quehenberger P, Mannhalter C, Lechner K. Risk of pregnancy-associated recurrent venous thromboembolism in women with a history of venous thrombosis. J Thromb Haemost 2005;3:949–54. https://doi.org/10.1111/j.1538-7836.2005.01307.x doi: 10.1111/j.1538-7836.2005.01307.x. [DOI] [PubMed]
  54. Brill-Edwards P, Ginsberg JS, Gent M, Hirsh J, Burrows R, Kearon C, et al.; Recurrence of Clot in This Pregnancy Study Group. Safety of withholding heparin in pregnant women with a history of venous thromboembolism. Recurrence of Clot in This Pregnancy Study Group. N Engl J Med 2000;343:1439–44. https://doi.org/10.1056/NEJM200011163432002 doi: 10.1056/NEJM200011163432002. [DOI] [PubMed]
  55. Sultan AA, Grainge MJ, West J, Fleming KM, Nelson-Piercy C, Tata LJ. Impact of risk factors on the timing of first postpartum venous thromboembolism: a population-based cohort study from England. Blood 2014;124:2872–80. https://doi.org/10.1182/blood-2014-05-572834 doi: 10.1182/blood-2014-05-572834. [DOI] [PMC free article] [PubMed]
  56. Blondon M, Casini A, Hoppe KK, Boehlen F, Righini M, Smith NL. Risks of venous thromboembolism after cesarean sections: a meta-analysis. Chest 2016;150:572–96. https://doi.org/10.1016/j.chest.2016.05.021 doi: 10.1016/j.chest.2016.05.021. [DOI] [PubMed]
  57. Sia WW, Powrie RO, Cooper AB, Larson L, Phipps M, Spencer P, et al. The incidence of deep vein thrombosis in women undergoing cesarean delivery. Thromb Res 2009;123:550–5. https://doi.org/10.1016/j.thromres.2008.06.004 doi: 10.1016/j.thromres.2008.06.004. [DOI] [PubMed]
  58. Macklon NS, Barry J, Greer IA. Duplex ultrasound screening for deep venous thrombosis in the puerperium. Br J Obstet Gynaecol 1995;102:255–6. https://doi.org/10.1111/j.1471-0528.1995.tb09104.x doi: 10.1111/j.1471-0528.1995.tb09104.x. [DOI] [PubMed]
  59. Kalro BN, Davidson RA, Owen P. Low incidence of asymptomatic deep venous thrombosis following caesarean section: a colour Doppler study. Health Bull (Edinb) 1999;57:418–21. [PubMed]
  60. Jacobsen AF, Drolsum A, Klow NE, Dahl GF, Qvigstad E, Sandset PM. Deep vein thrombosis after elective cesarean section. Thromb Res 2004;113:283–8. https://doi.org/10.1016/j.thromres.2004.03.008 doi: 10.1016/j.thromres.2004.03.008. [DOI] [PubMed]
  61. Goto M, Yoshizato T, Tatsumura M, Takashima T, Ogawa M, Nakahara H, et al. Safety and efficacy of thromboprophylaxis using enoxaparin sodium after cesarean section: a multi-center study in Japan. Taiwan J Obstet Gynecol 2015;54:248–52. https://doi.org/10.1016/j.tjog.2014.09.008 doi: 10.1016/j.tjog.2014.09.008. [DOI] [PubMed]
  62. Chan LYS, Lam KYM, Metreweli C, Lau TK. Duplex ultrasound screening for deep vein thrombosis in Chinese after cesarean section. Acta Obstet Gynecol Scand 2005;84:368–70. https://doi.org/10.1111/j.0001-6349.2005.00591.x doi: 10.1111/j.0001-6349.2005.00591.x. [DOI] [PubMed]
  63. Elgendy IY, Fogerty A, Blanco-Molina A, Rosa V, Schellong S, Skride A, et al. Clinical characteristics and outcomes of women presenting with venous thromboembolism during pregnancy and postpartum period: findings from the RIETE registry. Thromb Haemost 2020;120:1454–62. https://doi.org/10.1055/s-0040-1714211 doi: 10.1055/s-0040-1714211. [DOI] [PubMed]
  64. van Hoorn ME, Hague WM, van Pampus MG, Bezemer D, de Vries JIP; FRUIT Investigators Low-molecular-weight heparin and aspirin in the prevention of recurrent early-onset pre-eclampsia in women with antiphospholipid antibodies: the FRUIT-RCT. Eur J Obstet Gynecol Reprod Biol 2016;197:168–73. https://doi.org/10.1016/j.ejogrb.2015.12.011 doi: 10.1016/j.ejogrb.2015.12.011. [DOI] [PubMed]
  65. de Vries JIP, van Pampus MG, Hague WM, Bezemer PD, Joosten JH; FRUIT Investigators Low-molecular-weight heparin added to aspirin in the prevention of recurrent early-onset pre-eclampsia in women with inheritable thrombophilia: the FRUIT-RCT. J Thromb Haemost 2012;10:64–72. https://doi.org/10.1111/j.1538-7836.2011.04553.x doi: 10.1111/j.1538-7836.2011.04553.x. [DOI] [PubMed]
  66. Rodger MA, Hague WM, Kingdom J, Kahn SR, Karovitch A, Sermer M, et al.; TIPPS Investigators. Antepartum dalteparin versus no antepartum dalteparin for the prevention of pregnancy complications in pregnant women with thrombophilia (TIPPS): a multinational open-label randomised trial. Lancet 2014;384:1673–83. https://doi.org/10.1016/S0140-6736(14)60793-5 doi: 10.1016/S0140-6736(14)60793-5. [DOI] [PubMed]
  67. Gates S, Brocklehurst P, Ayers S, Bowler U; Thromboprophylaxis in Pregnancy Advisory Group. Thromboprophylaxis and pregnancy: two randomized controlled pilot trials that used low-molecular-weight heparin. Am J Obstet Gynecol 2004;191:1296–303. https://doi.org/10.1016/j.ajog.2004.03.039 doi: 10.1016/j.ajog.2004.03.039. [DOI] [PubMed]
  68. Burrows RF, Gan ET, Gallus AS, Wallace EM, Burrows EA. A randomised double-blind placebo controlled trial of low molecular weight heparin as prophylaxis in preventing venous thrombolic events after caesarean section: a pilot study. BJOG 2001;108:835–9. https://doi.org/10.1111/j.1471-0528.2001.00198.x doi: 10.1111/j.1471-0528.2001.00198.x. [DOI] [PubMed]
  69. Algahtani FH, Al-Dohami H, Abo-Harbesh S, Gader AGA, Aamer A. Thromboembolism prophylaxis after cesarean section (PRO-CS) trial. Thromb Res 2015;130:s197. https://doi.org/10.1016/j.thromres.2012.08.253
  70. Nelson-Piercy C, Powrie R, Borg JY, Rodger M, Talbot DJ, Stinson J, Greer IA. Tinzaparin use in pregnancy: an international, retrospective study of the safety and efficacy profile. Eur J Obstet Gynecol Reprod Biol 2011;159:293–9. https://doi.org/10.1016/j.ejogrb.2011.08.005 doi: 10.1016/j.ejogrb.2011.08.005. [DOI] [PubMed]
  71. Schoenbeck D, Nicolle A, Newbegin K, Hanley J, Loughney AD. The use of a scoring system to guide thromboprophylaxis in a high-risk pregnant population. Thrombosis 2011;2011:652796. https://doi.org/10.1155/2011/652796 doi: 10.1155/2011/652796. [DOI] [PMC free article] [PubMed]
  72. Cox S, Eslick R, McLintock C. Effectiveness and safety of thromboprophylaxis with enoxaparin for prevention of pregnancy-associated venous thromboembolism. J Thromb Haemost 2019;17:1160–70. https://doi.org/10.1111/jth.14452 doi: 10.1111/jth.14452. [DOI] [PubMed]
  73. Schulman S, Kearon C; Subcommittee on Control of Anticoagulation of the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis. Definition of major bleeding in clinical investigations of antihemostatic medicinal products in non-surgical patients. J Thromb Haemost 2005;3:692–4. https://doi.org/10.1111/j.1538-7836.2005.01204.x doi: 10.1111/j.1538-7836.2005.01204.x. [DOI] [PubMed]
  74. Lindqvist PG, Bremme K, Hellgren M; Working Group on Hemostatic Disorders (Hem-ARG), Swedish Society of Obstetrics and Gynecology. Efficacy of obstetric thromboprophylaxis and long-term risk of recurrence of venous thromboembolism. Acta Obstet Gynecol Scand 2011;90:648–53. https://doi.org/10.1111/j.1600-0412.2011.01098.x doi: 10.1111/j.1600-0412.2011.01098.x. [DOI] [PubMed]
  75. Royal College of Obstetricians & Gynaecologists. Thromboembolic Disease in Pregnancy and the Puerperium: Acute Management: Green-top Guideline No. 37b. London: Royal College of Obstetricians & Gynaecologists; 2015.
  76. Gizzo S, Noventa M, Anis O, Saccardi C, Zambon A, Di Gangi S, et al. Pharmacological anti-thrombotic prophylaxis after elective caesarean delivery in thrombophilia unscreened women: should maternal age have a role in decision making? J Perinat Med 2014;42:339–47. https://doi.org/10.1515/jpm-2013-0160 doi: 10.1515/jpm-2013-0160. [DOI] [PubMed]
  77. Ferres MA, Olivarez SA, Trinh V, Davidson C, Sangi-Haghpeykar H, Aagaard-Tillery KM. Rate of wound complications with enoxaparin use among women at high risk for postpartum thrombosis. Obstet Gynecol 2011;117:119–24. https://doi.org/10.1097/AOG.0b013e3182029180 doi: 10.1097/AOG.0b013e3182029180. [DOI] [PubMed]
  78. Knight M, Bunch K, Tuffnel D, Shakespeare J, Kotnis R, Kenyon S, et al. Saving Lives, Improving Mother’s Care: Lessons Learned to Inform Maternity Care from the UK and Ireland Confidential Enquiries into Maternal Deaths and Morbidity 2016–18. Oxford: National Perinatal Epidemiology Unity, University of Oxford; 2020.
  79. Ban L, Sprigg N, Abdul Sultan A, Nelson-Piercy C, Bath PM, Ludvigsson JF, et al. Incidence of first stroke in pregnant and nonpregnant women of childbearing age: a population-based cohort study from England. J Am Heart Assoc 2017;6(4):e004601. https://doi.org/10.1161/JAHA.116.004601 doi: 10.1161/JAHA.116.004601. [DOI] [PMC free article] [PubMed]
  80. Jerjes-Sanchez C, Rodriguez D, Farjat AE, Kayani G, MacCallum P, Lopes RD, et al.; GARFIELD-VTE Investigators. Pregnancy-associated venous thromboembolism: insights from GARFIELD-VTE. TH Open 2021;5:e24–34. https://doi.org/10.1055/s-0040-1722611 doi: 10.1055/s-0040-1722611. [DOI] [PMC free article] [PubMed]
  81. Nieto JA, Solano R, Ruiz-Ribo MD, Ruiz-Gimenez N, Prandoni P, Kearon C, Monreal M; Riete Investigators. Fatal bleeding in patients receiving anticoagulant therapy for venous thromboembolism: findings from the RIETE registry. J Thromb Haemost 2010;8:1216–22. https://doi.org/10.1111/j.1538-7836.2010.03852.x doi: 10.1111/j.1538-7836.2010.03852.x. [DOI] [PubMed]
  82. Ende-Verhaar YM, Cannegieter SC, Vonk Noordegraaf A, Delcroix M, Pruszczyk P, Mairuhu ATA, et al. Incidence of chronic thromboembolic pulmonary hypertension after acute pulmonary embolism: a contemporary view of the published literature. Eur Respir J 2017;49:1601792. https://doi.org/10.1183/13993003.01792-2016 doi: 10.1183/13993003.01792-2016. [DOI] [PubMed]
  83. Pengo V, Lensing AW, Prins MH, Marchiori A, Davidson BL, Tiozzo F, et al.; Thromboembolic Pulmonary Hypertension Study Group. Incidence of chronic thromboembolic pulmonary hypertension after pulmonary embolism. N Engl J Med 2004;350:2257–64. https://doi.org/10.1056/NEJMoa032274 doi: 10.1056/NEJMoa032274. [DOI] [PubMed]
  84. Kourlaba G, Relakis J, Kontodimas S, Holm MV, Maniadakis N. A systematic review and meta-analysis of the epidemiology and burden of venous thromboembolism among pregnant women. Int J Gynaecol Obstet 2016;132:4–10. https://doi.org/10.1016/j.ijgo.2015.06.054 doi: 10.1016/j.ijgo.2015.06.054. [DOI] [PubMed]
  85. Wik HS, Jacobsen AF, Sandvik L, Sandset PM. Prevalence and predictors for post-thrombotic syndrome 3 to 16 years after pregnancy-related venous thrombosis: a population-based, cross-sectional, case-control study. J Thromb Haemost 2012;10:840–7. https://doi.org/10.1111/j.1538-7836.2012.04690.x doi: 10.1111/j.1538-7836.2012.04690.x. [DOI] [PubMed]
  86. van Dongen CJJ, Prandoni P, Frulla M, Marchiori A, Prins MH, Hutten BA. Relation between quality of anticoagulant treatment and the development of the postthrombotic syndrome. J Thromb Haemost 2005;3:939–42. https://doi.org/10.1111/j.1538-7836.2005.01333.x doi: 10.1111/j.1538-7836.2005.01333.x. [DOI] [PubMed]
  87. Fogelholm R, Murros K, Rissanen A, Avikainen S. Long term survival after primary intracerebral haemorrhage: a retrospective population based study. J Neurol Neurosurg Psychiatry 2005;76:1534–8. https://doi.org/10.1136/jnnp.2004.055145 doi: 10.1136/jnnp.2004.055145. [DOI] [PMC free article] [PubMed]
  88. Liu S, Rouleau J, Joseph KS, Sauve R, Liston RM, Young D, Kramer MS. Epidemiology of pregnancy-associated venous thromboembolism: a population-based study in Canada. J Obstet Gynaecol Can 2009;31:611–20. https://doi.org/10.1016/S1701-2163(16)34240-2 doi: 10.1016/S1701-2163(16)34240-2. [DOI] [PubMed]
  89. Goodacre S, Horspool K, Shephard N, Pollard D, Hunt BJ, Fuller G, et al. Selecting pregnant or postpartum women with suspected pulmonary embolism for diagnostic imaging: the DiPEP diagnostic study with decision-analysis modelling. Health Technol Assess 2018;22:1–230. https://doi.org/10.3310/hta22470 doi: 10.3310/hta22470. [DOI] [PMC free article] [PubMed]
  90. Delcroix M, Lang I, Pepke-Zaba J, Jansa P, D’Armini AM, Snijder R, et al. Long-term outcome of patients with chronic thromboembolic pulmonary hypertension: results from an International Prospective Registry. Circulation 2016;133:859–71. https://doi.org/10.1161/CIRCULATIONAHA.115.016522 doi: 10.1161/CIRCULATIONAHA.115.016522. [DOI] [PubMed]
  91. Office for National Statistics. National Life Tables, England: 2016–18. London: Office for National Statistics; 2019.
  92. Joint Formulary Committee. British National Formulary (online). London: BMJ Group and Pharmaceutical Press; 2021.
  93. Menakaya CU, Pennington N, Muthukumar N, Joel J, Ramirez Jimenez AJ, Shaw CJ, Mohsen A. The cost of outpatient venous thromboembolism prophylaxis following lower limb injuries. Bone Joint J 2013;95-B:673–7. https://doi.org/10.1302/0301-620X.95B5.30555 doi: 10.1302/0301-620X.95B5.30555. [DOI] [PubMed]
  94. National Cost Collection. National Schedule of NHS Costs – Year 2018–19: NHS Trust and NHS Foundation. London: NHS England; 2020.
  95. McFarlane SQ, Patel JP, Auyeung V, Arya R. An international survey of low molecular weight heparin prescribing in the context of antenatal venous thromboembolism. Thromb Res 2021;200:99–101. https://doi.org/10.1016/j.thromres.2021.01.024 doi: 10.1016/j.thromres.2021.01.024. [DOI] [PubMed]
  96. Goodacre S, Nelson-Piercy C, Hunt BJ, Fuller G. Accuracy of PE rule-out strategies in pregnancy: secondary analysis of the DiPEP study prospective cohort. Emerg Med J 2020;37:423–8. https://doi.org/10.1136/emermed-2019-209213 doi: 10.1136/emermed-2019-209213. [DOI] [PMC free article] [PubMed]
  97. Knight M; UKOSS. Antenatal pulmonary embolism: risk factors, management and outcomes. BJOG 2008;115:453–61. https://doi.org/10.1111/j.1471-0528.2007.01622.x doi: 10.1111/j.1471-0528.2007.01622.x. [DOI] [PubMed]
  98. Luengo-Fernandez R, Yiin GS, Gray AM, Rothwell PM. Population-based study of acute- and long-term care costs after stroke in patients with AF. Int J Stroke 2013;8:308–14. https://doi.org/10.1111/j.1747-4949.2012.00812.x doi: 10.1111/j.1747-4949.2012.00812.x. [DOI] [PMC free article] [PubMed]
  99. Johnston JA, Brill-Edwards P, Ginsberg JS, Pauker SG, Eckman MH. Cost-effectiveness of prophylactic low molecular weight heparin in pregnant women with a prior history of venous thromboembolism. Am J Med 2005;118:503–14. https://doi.org/10.1016/j.amjmed.2004.12.009 doi: 10.1016/j.amjmed.2004.12.009. [DOI] [PubMed]
  100. Pickering K, Gallos ID, Williams H, Price MJ, Merriel A, Lissauer D, et al. Uterotonic drugs for the prevention of postpartum haemorrhage: a cost-effectiveness analysis. PharmacoEconomics Open 2019;3:163–76. https://doi.org/10.1007/s41669-018-0108-x doi: 10.1007/s41669-018-0108-x. [DOI] [PMC free article] [PubMed]
  101. Richardson J, Hollier-Hann G, Kelly K, Chiara Alvisi M, Winter C, Cetin I, et al. A study of the healthcare resource use for the management of postpartum haemorrhage in France, Italy, the Netherlands, and the UK. Eur J Obstet Gynecol Reprod Biol 2022;268:92–9. https://doi.org/10.1016/j.ejogrb.2021.11.432 doi: 10.1016/j.ejogrb.2021.11.432. [DOI] [PubMed]
  102. Caprini JA, Botteman MF, Stephens JM, Nadipelli V, Ewing MM, Brandt S, et al. Economic burden of long-term complications of deep vein thrombosis after total hip replacement surgery in the United States. Value Health 2003;6:59–74. https://doi.org/10.1046/j.1524-4733.2003.00204.x doi: 10.1046/j.1524-4733.2003.00204.x. [DOI] [PubMed]
  103. Etxeandia-Ikobaltzeta I, Zhang Y, Brundisini F, Florez ID, Wiercioch W, Nieuwlaat R, et al. Patient values and preferences regarding VTE disease: a systematic review to inform American Society of Hematology guidelines. Blood Adv 2020;4:953–68. https://doi.org/10.1182/bloodadvances.2019000462 doi: 10.1182/bloodadvances.2019000462. [DOI] [PMC free article] [PubMed]
  104. Chuang LH, Gumbs P, van Hout B, Agnelli G, Kroep S, Monreal M, et al. Health-related quality of life and mortality in patients with pulmonary embolism: a prospective cohort study in seven European countries. Qual Life Res 2019;28:2111–24. https://doi.org/10.1007/s11136-019-02175-z doi: 10.1007/s11136-019-02175-z. [DOI] [PMC free article] [PubMed]
  105. Monreal M, Agnelli G, Chuang LH, Cohen AT, Gumbs PD, Bauersachs R, et al. Deep vein thrombosis in Europe-Health-Related Quality of Life and Mortality. Clin Appl Thromb Hemost 2019;25:1076029619883946. https://doi.org/10.1177/1076029619883946 doi: 10.1177/1076029619883946. [DOI] [PMC free article] [PubMed]
  106. Enden T, Wik HS, Kvam AK, Haig Y, Klow NE, Sandset PM. Health-related quality of life after catheter-directed thrombolysis for deep vein thrombosis: secondary outcomes of the randomised, non-blinded, parallel-group CaVenT study. BMJ Open 2013;3:e002984. https://doi.org/10.1136/bmjopen-2013-002984 doi: 10.1136/bmjopen-2013-002984. [DOI] [PMC free article] [PubMed]
  107. Lenert LA, Soetikno RM. Automated computer interviews to elicit utilities: potential applications in the treatment of deep venous thrombosis. J Am Med Inform Assoc 1997;4:49–56. https://doi.org/10.1136/jamia.1997.0040049 doi: 10.1136/jamia.1997.0040049. [DOI] [PMC free article] [PubMed]
  108. Hach-Wunderle V, Bauersachs R, Gerlach HE, Eberle S, Schellong S, Riess H, et al. Post-thrombotic syndrome 3 years after deep venous thrombosis in the Thrombosis and Pulmonary Embolism in Out-Patients (TULIPA) PLUS Registry. J Vasc Surg Venous Lymphat Disord 2013;1:5–12. https://doi.org/10.1016/j.jvsv.2012.07.003 doi: 10.1016/j.jvsv.2012.07.003. [DOI] [PubMed]
  109. Meads DM, McKenna SP, Doughty N, Das C, Gin-Sing W, Langley J, Pepke-Zaba J. The responsiveness and validity of the CAMPHOR Utility Index. Eur Respir J 2008;32:1513–9. https://doi.org/10.1183/09031936.00069708 doi: 10.1183/09031936.00069708. [DOI] [PubMed]
  110. Luengo-Fernandez R, Gray AM, Bull L, Welch S, Cuthbertson F, Rothwell PM; Oxford Vascular Study. Quality of life after TIA and stroke: ten-year results of the Oxford vascular study. Neurology 2013;81:1588–95. https://doi.org/10.1212/WNL.0b013e3182a9f45f doi: 10.1212/WNL.0b013e3182a9f45f. [DOI] [PMC free article] [PubMed]
  111. Marchetti M, Pistorio A, Barone M, Serafini S, Barosi G. Low-molecular-weight heparin versus warfarin for secondary prophylaxis of venous thromboembolism: a cost-effectiveness analysis. Am J Med 2001;111:130–9. https://doi.org/10.1016/s0002-9343(01)00793-8 doi: 10.1016/s0002-9343(01)00793-8. [DOI] [PubMed]
  112. Ara R, Brazier JE. Using health state utility values from the general population to approximate baselines in decision analytic models when condition-specific data are not available. Value Health 2011;14:539–45. https://doi.org/10.1016/j.jval.2010.10.029 doi: 10.1016/j.jval.2010.10.029. [DOI] [PubMed]
  113. Voke J, Keidan J, Pavord S, Spencer NH, Hunt BJ; British Society for Haematology Obstetric Haematology Group. The management of antenatal venous thromboembolism in the UK and Ireland: a prospective multicentre observational survey. Br J Haematol 2007;139:545–58. https://doi.org/10.1111/j.1365-2141.2007.06826.x doi: 10.1111/j.1365-2141.2007.06826.x. [DOI] [PubMed]
  114. Sultan AA, Tata LJ, West J, Fiaschi L, Fleming KM, Nelson-Piercy C, et al. Risk factors for first venous thromboembolism around pregnancy: a population-based cohort study from the United Kingdom. Blood 2013;121(19):3952–61. https://doi.org/10.1182/blood-2012-11-469551 doi: 10.1182/blood-2012-11-469551. [DOI] [PubMed]
  115. Strong M, Oakley JE, Brennan A. Estimating multiparameter partial expected value of perfect information from a probabilistic sensitivity analysis sample: a nonparametric regression approach. Med Decis Making 2014;34:311–26. https://doi.org/10.1177/0272989X13505910 doi: 10.1177/0272989X13505910. [DOI] [PMC free article] [PubMed]
  116. Kunst N, Wilson ECF, Glynn D, Alarid-Escudero F, Baio G, Brennan A, et al.; Collaborative Network for Value of Information. Computing the expected value of sample information efficiently: practical guidance and recommendations for four model-based methods. Value Health 2020;23:734–42. https://doi.org/10.1016/j.jval.2020.02.010 doi: 10.1016/j.jval.2020.02.010. [DOI] [PMC free article] [PubMed]
  117. Office for National Statistics. Births in England and Wales: 2019. London: Office for National Statistics; 2020.
  118. Ziauddeen N, Wilding S, Roderick PJ, Macklon NS, Alwan NA. Is maternal weight gain between pregnancies associated with risk of large-for-gestational age birth? Analysis of a UK population-based cohort. BMJ Open 2019;9:e026220. https://doi.org/10.1136/bmjopen-2018-026220 doi: 10.1136/bmjopen-2018-026220. [DOI] [PMC free article] [PubMed]
  119. van der Zande ISE, van der Graaf R, Hooft L, van Delden JJM. Facilitators and barriers to pregnant women’s participation in research: a systematic review. Women Birth 2018;31:350–61. https://doi.org/10.1016/j.wombi.2017.12.009 doi: 10.1016/j.wombi.2017.12.009. [DOI] [PubMed]
  120. Rodger MA, Makropoulos D, Walker M, Keely E, Karovitch A, Wells PS. Participation of pregnant women in clinical trials: will they participate and why? Am J Perinatol 2003;20:69–76. https://doi.org/10.1055/s-2003-38318 doi: 10.1055/s-2003-38318. [DOI] [PubMed]
  121. Braun V, Clarke V. One size fits all? What counts as quality practice in (reflexive) thematic analysis? Qual Res Psychol 2021;18:328–52. https://doi.org/10.1080/14780887.2020.1769238
  122. Strong M, Oakley JE, Brennan A, Breeze P. Estimating the expected value of sample information using the probabilistic sensitivity analysis sample: a fast, nonparametric regression-based method. Med Decis Making 2015;35:570–83. https://doi.org/10.1177/0272989X15575286 doi: 10.1177/0272989X15575286. [DOI] [PMC free article] [PubMed]
  123. Reps JM, Ryan PB, Rijnbeek PR, Schuemie MJ. Design matters in patient-level prediction: evaluation of a cohort vs. case-control design when developing predictive models in observational healthcare datasets. J Big Data 2021;8:108. https://doi.org/10.1186/s40537-021-00501-2
  124. Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, et al. Cochrane Handbook for Systematic Reviews of Interventions Version 6.2 (Updated February 2021). Cochrane; 2021. URL: www.training.cochrane.org (accessed 5 February 2000).
  125. Smyth RMD, Jacoby A, Elbourne D. Deciding to join a perinatal randomised controlled trial: experiences and views of pregnant women enroled in the Magpie Trial. Midwifery 2012;28:E478–85. https://doi.org/10.1016/j.midw.2011.08.006 doi: 10.1016/j.midw.2011.08.006. [DOI] [PubMed]
  126. van der Zande ISE, van der Graaf R, Oudijk MA, van Vliet-Lachotzki EH, van Delden JJM. A qualitative study on stakeholders’ views on the participation of pregnant women in the APOSTEL VI study: a low-risk obstetrical RCT. BMC Pregnancy Childbirth 2019;19:65. https://doi.org/10.1186/s12884-019-2209-7 doi: 10.1186/s12884-019-2209-7. [DOI] [PMC free article] [PubMed]
  127. Hanrahan V, Gillies K, Biesty L. Recruiters’ perspectives of recruiting women during pregnancy and childbirth to clinical trials: a qualitative evidence synthesis. PLOS ONE 2020;15:e0234783. https://doi.org/10.1371/journal.pone.0234783 doi: 10.1371/journal.pone.0234783. [DOI] [PMC free article] [PubMed]
  128. Tooher RL, Middleton PF, Crowther CA. A thematic analysis of factors influencing recruitment to maternal and perinatal trials. BMC Pregnancy Childbirth 2008;8:36. https://doi.org/10.1186/1471-2393-8-36 doi: 10.1186/1471-2393-8-36. [DOI] [PMC free article] [PubMed]
  129. Renert H, Russell-Mayhew S, Arthur N. Recruiting ethnically diverse participants into qualitative health research: lessons learned. Qual Rep 2013;18:1–13. https://doi.org/10.46743/2160-3715/2013.1542
  130. Rooney LK, Bhopal R, Halani L, Levy ML, Partridge MR, Netuveli G, et al. Promoting recruitment of minority ethnic groups into research: qualitative study exploring the views of South Asian people with asthma. J Public Health (Oxf) 2011;33:604–15. https://doi.org/10.1093/pubmed/fdq100 doi: 10.1093/pubmed/fdq100. [DOI] [PubMed]
  131. Hanrahan V, Biesty L, Lawrie L, Duncan E, Gillies K. Theory-guided interviews identified _behavioral barriers and enablers to healthcare professionals recruiting participants to maternity trials. J Clin Epidemiol 2022;145:81–91. https://doi.org/10.1016/j.jclinepi.2022.01.015 doi: 10.1016/j.jclinepi.2022.01.015. [DOI] [PubMed]
  132. James A, Birsner M, Kaimal A; in Collaboration with American College of Obstetricians and Gynecologists’ Committee on Practice Bulletins-Obstetrics. ACOG Practice Bulletin No. 196 Summary: thromboembolism in pregnancy. Obstet Gynecol 2018;132:243–8. https://doi.org/10.1097/AOG.0000000000002707
  133. Lindqvist PG, Hellgren M. Obstetric thromboprophylaxis: the Swedish guidelines. Adv Hematol 2011;2011:157483. https://doi.org/10.1155/2011/157483 doi: 10.1155/2011/157483. [DOI] [PMC free article] [PubMed]
  134. Wu O, Robertson L, Twaddle S, Lowe GDO, Clark P, Greaves M, et al. Screening for thrombophilia in high-risk situations: systematic review and cost-effectiveness analysis. The Thrombosis: Risk and Economic Assessment of Thrombophilia Screening (TREATS) study. Health Technol Assess 2006;10:1–110. https://doi.org/10.3310/hta10110 doi: 10.3310/hta10110. [DOI] [PubMed]
  135. Wu O, Robertson L, Twaddle S, Lowe G, Clark P, Walker I, et al.; Thrombosis: Risk and Economic Assessment of Thrombophilia Screening (TREATS) Study. Screening for thrombophilia in high-risk situations: a meta-analysis and cost-effectiveness analysis. Br J Haematol 2005;131:80–90. https://doi.org/10.1111/j.1365-2141.2005.05715.x
  136. Wu O, Greer IA. Is screening for thrombophilia cost-effective? Curr Opin Hematol 2007;14:500–3. https://doi.org/10.1097/MOH.0b013e32825f5318 doi: 10.1097/MOH.0b013e32825f5318. [DOI] [PubMed]
  137. Wormer KC, Jangda AA, El Sayed FA, Stewart KI, Mumford SL, Segars JH. Is thromboprophylaxis cost effective in ovarian hyperstimulation syndrome: a systematic review and cost analysis. Eur J Obstet Gynecol Reprod Biol 2018;224:117–24. https://doi.org/10.1016/j.ejogrb.2018.03.028 doi: 10.1016/j.ejogrb.2018.03.028. [DOI] [PMC free article] [PubMed]
  138. Westhoff G, Yanit K, Volpe KA, Pilliod R, Doss A, Rodriguez M, Caughey AB. The cost-effectiveness of thromboprophylaxis with low-molecular weight heparin or unfractionated heparin after cesarean delivery. Am J Obstet Gynecol 2012;206:S366. https://doi.org/10.1016/j.ajog.2011.10.854
  139. Sievert A, Hernandez M, Hersh AR, Harmon D, Caughey AB. Pregnancy-adapted years algorithm for diagnosing suspected pulmonary embolism: a cost-effectiveness analysis. Obstet Gynecol 2020;135:131S. https://doi.org/10.1097/01.AOG.0000664664.88371.1c
  140. Sabol BA, Rosenbloom JI, Cahill AG, Macones GA. 832: Universal screening of inherited thrombophilias to reduce venous thromboembolism risk in pregnancy: a decision analysis. Am J Obstet Gynecol 2019;220:S543–4. https://doi.org/10.1016/j.ajog.2018.11.855
  141. Rizvi AH, Smith KJ, Ragni MV. Cost-effectiveness of thromboprophylaxis in pregnant women with sickle cell disease. Blood 2013;122:426. https://doi.org/10.1182/blood.V122.21.426.426
  142. Quinones JN, James DN, Stamilio DM, Cleary KL, Macones GA. Thromboprophylaxis after cesarean delivery: a decision analysis. Obstet Gynecol 2005;106:733–40. https://doi.org/10.1097/01.AOG.0000178792.51401.3a doi: 10.1097/01.AOG.0000178792.51401.3a. [DOI] [PubMed]
  143. Pollard D, Goodacre S, Stevenson M, Fuller G. Decision analysis modelling of diagnostic strategies for suspected pulmonary embolism in pregnancy: the DiPEP economic evaluation. Emerg Med J 2017;34:A867–8. https://doi.org/10.1136/emermed-2017-207308.10
  144. Lee VR, Westhoff GL, Pilliod RA, Yanit KE, Caughey AB. Cost-effectiveness of post-cesarean pharmacologic VTE prophylaxis in obese women. Am J Obstet Gynecol 2017;216:S232–3. https://doi.org/10.1016/j.ajog.2016.11.645
  145. Iroz CB, Dahl CM, Cassimatis IR, Wescott AB, Miller ES. Prophylactic anticoagulation for preterm premature rupture of membranes: a decision analysis. Am J Obstet Gynecol MFM 2021;3:100311. https://doi.org/10.1016/j.ajogmf.2021.100311 doi: 10.1016/j.ajogmf.2021.100311. [DOI] [PubMed]
  146. Houlihan M, Higgins J, Ismail S, Murphy A. Prospective cost analysis of low molecular weight heparin thromboprophylaxis post-planned caesarean section. Ir J Med Sci 2017;186:S178. https://doi.org/10.1007/s11845-017-1629-5
  147. Eckman MH, Alonso-Coello P, Guyatt GH, Ebrahim S, Tikkinen KAO, Lopes LC, et al. Women’s values and preferences for thromboprophylaxis during pregnancy: a comparison of direct-choice and decision analysis using patient specific utilities. Thromb Res 2015;136:341–7. https://doi.org/10.1016/j.thromres.2015.05.020 doi: 10.1016/j.thromres.2015.05.020. [DOI] [PMC free article] [PubMed]
  148. Dahl CM, Iroz C, Wescott A, Cassimatis I, Miller ES. Prophylactic anticoagulation while hospitalized for premature prelabor rupture of membranes: a decision analysis. Obstet Gynecol 2020;135:132S. https://doi.org/10.1097/01.AOG.0000664672.29477.41
  149. Casele H, Grobman WA. Cost-effectiveness of thromboprophylaxis with intermittent pneumatic compression at cesarean delivery. Obstet Gynecol 2006;108:535–40. https://doi.org/10.1097/01.AOG.0000227780.76353.05 doi: 10.1097/01.AOG.0000227780.76353.05. [DOI] [PubMed]
  150. Bunce E, Sheperd JP, Paruchuri Y, Simhan HN. Optimal Strategy for Venous Thromboembolism Prophylaxis Following Cesarean Delivery: A Decision Analysis. Am J Obstet Gynecol 2017;216:S379–80.
  151. Blondon M, Perrier A, Nendaz M, Righini M, Boehlen F, Boulvain M, De Moerloose P. Thromboprophylaxis with low-molecular-weight heparin after cesarean delivery: a decision analysis. Thromb Haemost 2010;103:129–37. https://doi.org/10.1160/TH09-06-0349 doi: 10.1160/TH09-06-0349. [DOI] [PubMed]
  152. Becker DA, Einerson BD, Wetta LL, Kuper SG, Casey BM, Subramaniam A. 742: Postpartum venous thromboembolism prophylaxis: a cost-effectiveness analysis. Am J Obstet Gynecol 2019;220:S487–8. https://doi.org/10.1016/j.ajog.2018.11.765
  153. Bajaj PS, Veenstra DL. A risk-benefit analysis of factor V Leiden testing to improve pregnancy outcomes: a case study of the capabilities of decision modeling in genomics. Genet Med 2013;15:374–81. https://doi.org/10.1038/gim.2012.139 doi: 10.1038/gim.2012.139. [DOI] [PubMed]
  154. National Clinical Guideline Centre. Venous Thromboembolism: Reducing the Risk for Patients in Hospital. London: Royal College of Physicians (UK); 2012.

RESOURCES