Diagnosis of pregnancy-associated venous thromboembolism - position paper of the Working Group in Women’s Health of the Society of Thrombosis and Haemostasis (GTH)

Abstract

EpidemiologyVTE is a leading cause of maternal morbidity in the developed world and, in the case of PE, of mortality as well [1]. While the relative risk of VTE is greatly increased during pregnancy compared with that in non-pregnant women, the absolute risk remains low: estimates of the incidence of pregnancy-associated VTE have varied from 1:500 to 1:1500 pregnancies [2 -7]. The risk of VTE is approximately 5-fold greater in pregnant women than in non-pregnant women.Approximately 80 % of pregnancy-associated VTEs are isolated DVTs, and approximately 20 % are PEs or both DVTs and PEs [5]. Although a systematic review reported weighted event rates for DVT of 21.9 %, 33.7 % and 47.6 % for the fi rst, second and third trimesters, respectively [6], a recent study suggested that the risk might in fact increase exponentially over the duration of the pregnancy [7], with 12.4 % of VTEs diagnosed in the fi rst trimester, 15.3 % in the second trimester and 72.3 % in the third trimester. This detailed risk assessment for each gestational week demonstrated a 21-fold increased risk for the last two weeks before delivery [7]. Summary: Pregnancy and the postpartum period are associated with an increased risk of venous thromboembolism (VTE). Over the past decade, new diagnostic algorithms have been established, combining clinical probability, laboratory testing and imaging studies for the diagnosis of deep vein thrombosis (DVT) and pulmonary embolism (PE) in the non-pregnant population. However, there is no such generally accepted algorithm for the diagnosis of pregnancy-associated VTE. Studies establishing clinical prediction rules have excluded pregnant women, and prediction scores currently in use have not been prospectively validated in pregnancy or during the postpartum period. D-dimers physiologically increase throughout pregnancy and peak at delivery, so a negative D-dimer test result, based on the reference values of non-pregnant subjects, becomes unlikely in the second and third trimesters. Imaging studies therefore play a major role in confi rming suspected DVT or PE in pregnant women. Major concerns have been raised against radiologic imaging because of foetal radiation exposure, and doubts about the diagnostic value of ultrasound techniques in attempting to exclude isolated iliac vein thrombosis grow stronger as pregnancy progresses. As members of the Working Group in Women's Health of the Society of Thrombosis and Haemostasis (GTH), we summarise evidence from the available literature and aim to establish a more uniform strategy for diagnosing pregnancy-associated VTE. Review Diagnosis of pregnancy-associated

Impact of fetal maceration grade on risk of maternal disseminated intravascular coagulation after intrauterine fetal death – A retrospective cohort study

“…The strengths of this study are, firstly, its strict inclusion and exclusion criteria, resulting in a homogenous cohort limited to singleton IUFDs and devoid of any obvious maternal or fetal risk factors for DIC, apart from the fetal maceration grade, which was subject to our hypothesis. Secondly, we applied the Erez score instead of the International Society for Thrombosis and Hemostasis (ISTH) scoring system for DIC 47 , since evaluation of D-Dimer has not been routinely assessed in this cohort due to its poor positive predictive value in pregnancy 48 , 49 . The Erez score, however, puts emphasis on the PC count, and thrombocytopenia has been appreciated as one of the commonest diagnostic features for DIC 50 .…”

Pregnancy as a predictor of deviations from the recommended diagnostic pathway in women with suspected pulmonary embolism: ZATPOL registry data

“…In line with the 2011 guidelines, VTE risk should be assessed in all women in early pregnancy, as well as in those planning to get pregnant. Based on the result, each woman should be assigned to one out of three VTE risk categories and appropriate preventive measures need to be implemented [ 13 , 14 ].…”

“…However, the exposure to the maternal breast tissue during chest angio-CT is estimated to be in the range 10–70 mSv [ 1 ]. Exposure to radiation is thought to increase lifelong risk of breast and lung cancer in exposed women [ 14 ]. It needs to be underlined that PE is a life-threatening disease and therefore one should not hesitate to use all recommended diagnostic methods including those with ionizing radiation [ 1 ].…”

“…Both methods are at risk of inconclusive results, but among pregnant patients this probability is higher for angio-CT. However, in pregnant women with abnormal chest X-ray, the rate of nondiagnostic ventilation-perfusion scans is significantly higher [ 14 , 16 ]. There are two ongoing trials aimed at clarifying unsolved issues of the diagnostic pathway in pregnant women [ 17 ].…”

Kontrazeption und venöse Thromboembolie

“…The risk of VTE in women of child-bearing age is low at about 2 -5/10,000 per year (2). Pregnancy is associated with a considerable, roughly 6-fold higher risk of VTE and this increases by as much as 22 times during the post-partum period (3,4).…”