Society of Obstetric Medicine of Australia and New Zealand
Recommendations from the Society of Obstetric Medicine of Australia and New Zealand on testing for venous thromboembolism, inherited thrombophilia, proteinuria in established pre-eclampsia, and erythrocyte sedimentation rate (ESR) in pregnancy. The Society of Obstetric Medicine of Australia and New Zealand aims to advance clinical and scientific knowledge of hypertensive diseases and medical disorders in pregnancy and to foster collaboration with other regional and international societies interested in hypertension in pregnancy and obstetric medicine.
Do not test for inherited thrombophilia for placental mediated complications
While older retrospective studies suggested that inherited thrombophilia is associated with adverse pregnancy outcomes such as stillbirth, recurrent miscarriage and placental abruption, more recent and more rigorous studies have either failed to find an association or have found only a weak association. Moreover, the association is a moot point as there is now good quality evidence from randomised controlled trials that low-molecular-weight heparin does not significantly reduce the rate of placental mediated complications.
As evidence and clinical practice advances, Evolve recommendations will reflect these changes following a review. The latest SOMANZ recommendation developments are outlined below
Removal of recommendation (2019)
The previous iteration of the SOMANZ ‘Top-Five’ recommendations included:
Do not perform a D-Dimer test for the exclusion of venous thromboembolism during any trimester of pregnancy.
Recent studies have shown that using a D-Dimer in combination with a clinical algorithm can increase the reliability of D-Dimer testing in ruling out DVT and PE in pregnancy.
Furthermore, the alternative to D-Dimer tests for these purposes is the use of imaging tests, which have their own set of risks from radiation exposure. Where previous evidence which suggested D-Dimer testing was highly unreliable would have tipped the scales towards discouraging D-Dimer testing, the new evidence suggests the results of D-Dimer testing can be made more reliable. Thus, it is no longer apparent there would be strong benefits from discouraging the use of D-Dimer testing in these settings if the alternative is imaging.
At a 7 August 2019 meeting of the SOMANZ Council it was agreed this recommendation be removed. The RACP Evolve team and the NPS MedicineWise Choosing Wisely Australia Clinical Lead also undertook a review.
Due to this change in evidence, and physician support, this recommendation was officially removed in August 2019.
Supporting evidence for the removal of this recommendation
- Langlois E, Cusson-Dufour C, Moumneh T, et al. Could the YEARS algorithm be used to exclude pulmonary embolism during pregnancy? Data from the CT-PE-pregnancy study. J Thromb Haemost. 2019;17(8):1329-1334
- van der Pol LM, Tromeur C, Bistervels IM, et al. Pregnancy-Adapted YEARS Algorithm for Diagnosis of Suspected Pulmonary Embolism. N Engl J Med 2019; 380:1139-1149.*
Original Recommendation: Do not perform a D-Dimer test for the exclusion of venous thromboembolism during any trimester of pregnancy
As D-Dimer levels are raised during pregnancy, they do not have a high positive predictive value for venous thromboembolism (VTE) in pregnancy (i.e. they are unreliable for ruling in VTE in pregnancy). However, nor are they a reliable rule-out test for VTE. One study estimated the sensitivity of the D-Dimer test at 73 per cent, meaning that 27 per cent of patients with a negative D-Dimer had VTE. There have also been case reports of pregnant women with pulmonary embolism presenting with a negative D-Dimer. Therefore, there is no value in performing a D-Dimer test for the exclusion of venous thromboembolism at any trimester in pregnancy.
- Damodaram M, Kaladindi M, Luckit J, et al. D-dimers as a screening test for venous thromboembolism in pregnancy: is it of any use? Journal of Obstetrics and Gynaecology 2009; 29(2):101-32.
- 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; 52(1):14-22.
- To MS, Hunt BJ, Nelson-Piercy C. A negative D-Dimer does not exclude venous thromboembolism in pregnancy. Journal of Obstetrics and Gynaecology 2008; 28(2):222-40.
- Clark P, Walker ID, Langhorne P, et al. SPIN: the Scottish Pregnancy Intervention Study: a multicentre randomised controlled trial of low molecular weight heparin and low dose aspirin in women with recurrent miscarriage. Blood 2010; 115(21):4162-7.
- Rodger MA, Walker MC, Smith GN, et al. Is thrombophilia associated with placenta-mediated pregnancy complications? A prospective cohort study. J of Thrombosis & Haemostasis 2014; 12:469-78.
- Rodger MA, Hague WM, Kingdom J, et al. 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.
- Said JM, Higgins JR, Moses EK, et al. Inherited thrombophilias and adverse pregnancy outcomes: a case-control study in an Australian population. Acta Obstet Gynecol Scand 2012; 91(2):250-5.
- Silver RM, Saade GR, Thorsten V, et al. Factor V Leiden, prothrombin G20210A, and methylene tetrahydrofolate reductase mutations and stillbirth: the Stillbirth Collaborative Research Network. Am J Obstet Gynecol 2016; 215:468.e1-17.
SOMANZ Council members considered potential low value clinical practices in obstetric medicine of relevance to SOMANZ members, and developed a shortlist of nine items. Council members then worked with the RACP to compile and review the published research on each of these practices. Based on the review, the list of potential items of interest was refined down to seven and recommendations for these were formulated.
All Fellows and advanced trainees of SOMANZ were surveyed online for their views on these seven draft recommendations and provided with evidence summaries for each, and for their suggestions of other practices not already included. They were asked to score each recommendation based on whether they thought it was evidence based, currently undertaken in significant volume, and important for reducing harms and/or unnecessary healthcare costs. Based on the scores and feedback, the final top-five recommendations were then finalised and approved by SOMANZ Council.
- 1 Do not test for inherited thrombophilia for placental mediated complications
- 2 Do not do repeat testing for proteinuria in established pre-eclampsia
- 3 Do not undertake methylenetetrahydrofolate reductase (MTHFR) polymorphism testing as part of a routine evaluation for thrombophilia in pregnancy
- 4 Do not measure erythrocyte sedimentation rate (ESR) in pregnancy