The use of D-dimer with new cutoff can be useful in diagnosis of venous thromboembolism in pregnancy

The role of D-dimer changes in predicting delivery time in preterm premature rupture of membranes: a retrospective analysis

INTRODUCTION

Pregnancy induces a hypercoagulable state, characterized by increased coagulation factors and decreased anticoagulants, alongside ongoing fibrinolysis marked by elevated D-dimer (DD) levels. Reference values for DD in pregnancy often exceed the non-pregnant cutoff due to these changes. Elevated DD levels are common in late pregnancy and may correlate with complications such as gestational diabetes, hypertension, and preterm delivery, particularly in cases of preterm premature rupture of membranes (PPROM). This study investigates the association between DD levels, the duration from PPROM diagnosis to delivery, and neonatal outcomes.

METHODS

This retrospective study was conducted at the Department of Perinatology, Etlik City Hospital, Ankara, Turkey, from October 2022 to May 2023. Eighty patients with PPROM between 24 and 36 weeks of gestation were included. Routine blood tests and coagulation parameters, including DD, were monitored every other day for 2 weeks. Patients were classified into two subgroups based on whether labor occurred within 7 days of PPROM diagnosis. Statistical analyses included the Mann-Whitney U test, Student's t test, Chi-square test, Friedman test, Durbin-Conover test, generalized estimating equations (GEE), and ROC analysis.

RESULTS

Gestational age at admission was significantly lower in patients who delivered later than 7 days post-PPROM. Significant differences were observed in ultrasonographic measurements, with larger fetal parameters in the early delivery group. Higher DD levels at the third follow-up correlated with shorter durations to delivery (p = 0.021). Longitudinal analysis showed significant fluctuations in DD levels over time, particularly near delivery. The GEE analysis demonstrated a strong inverse relationship between DD levels and time to delivery (p = 0.004), supported by ROC analysis (AUROC = 0.811).

CONCLUSIONS

Elevated DD levels are associated with shorter durations from PPROM diagnosis to delivery, indicating their potential utility in predicting labor onset. Monitoring DD levels may help in clinical decision-making for managing PPROM, including planning neonatal care and timing of interventions.

Associations of serum D-dimer and glycosylated hemoglobin levels with third-trimester fetal growth restriction in gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) is a special type of diabetes that commonly occurs in women during pregnancy and involves impaired glucose tolerance and abnormal glucose metabolism; GDM is diagnosed for the first time during pregnancy and can affect fetal growth and development.

AIM

To investigate the associations of serum D-dimer (D-D) and glycosylated hemoglobin (HbA1c) levels with third-trimester fetal growth restriction (FGR) in GDM patients.

METHODS

The clinical data of 164 pregnant women who were diagnosed with GDM and delivered at the Obstetrics and Gynecology Hospital of Fudan University from January 2021 to January 2023 were analyzed retrospectively. Among these women, 63 whose fetuses had FGR were included in the FGR group, and 101 women whose fetuses had normal body weights were included in the normal body weight group (normal group). Fasting venous blood samples were collected from the elbow at 28-30 wk gestation and 1-3 d before delivery to measure serum D-D and HbA1c levels for comparative analysis. The diagnostic value of serum D-D and HbA1c levels for FGR was evaluated by receiver operating characteristic analysis, and the influencing factors of third-trimester FGR in GDM patients were analyzed by logistic regression.

RESULTS

Serum fasting blood glucose, fasting insulin, D-D and HbA1c levels were significantly greater in the FGR group than in the normal group, while the homeostasis model assessment of insulin resistance values were lower (P < 0.05). Regarding the diagnosis of FGR based on serum D-D and HbA1c levels, the areas under the curves (AUCs) were 0.826 and 0.848, the cutoff values were 3.04 mg/L and 5.80%, the sensitivities were 81.0% and 79.4%, and the specificities were 88.1% and 87.1%, respectively. The AUC of serum D-D plus HbA1c levels for diagnosing FGR was 0.928, and the sensitivity and specificity were 84.1% and 91.1%, respectively. High D-D and HbA1c levels were risk factors for third-trimester FGR in GDM patients (P < 0.05).

CONCLUSION

D-D and HbA1c levels can indicate the occurrence of FGR in GDM patients in the third trimester of pregnancy to some extent, and their combination can be used as an important index for the early prediction of FGR.

Pulmonary Embolism in Pregnancy: A Review for Clinical Practitioners

Diagnostic and therapeutic decision-making in pregnancy with suspected pulmonary embolism (PE) is challenging. European and other international professional societies have proposed various recommendations that are ambiguous, probably due to the unavailability of randomized controlled trials. In the following sections, we discuss the supporting diagnostic steps and treatments. We suggest a standardized diagnostic work-up in pregnant patients presenting with symptoms of PE to make evidence-based diagnostic and therapeutic decisions. We strongly recommend that clinical decisions on treatment in pregnant patients with intermediate- or high-risk pulmonary embolism should include a multidisciplinary team approach involving emergency physicians, pulmonologists, angiologist, cardiologists, thoracic and/or cardiovascular surgeons, radiologists, and obstetricians to choose a tailored management option including an interventional treatment. It is important to be aware of the differences among guidelines and to assess each case individually, considering the specific views of the different specialties. This review summarizes key concepts of the diagnostics and acute management of pregnant women with suspected PE that are supportive for the clinician on duty.

IAS-FET: An intelligent assistant system and an online platform for enhancing successful rate of in-vitro fertilization embryo transfer technology based on clinical features

BACKGROUND

Among all of the assisted reproductive technology (ART) methods, in vitro fertilization-embryo transfer (IVF-ET) holds a prominent position as a key solution for overcoming infertility. However, its success rate hovers at a modest 30% to 70%. Adding to the challenge is the absence of effective models and clinical tools capable of predicting the outcome of IVF-ET before embryo formation. Our study is dedicated to filling this critical gap by aiming to predict IVF-ET outcomes and ultimately enhance the success rate of this transformative procedure.

METHODS

In this retrospective study, infertile patients who received artificial assisted pregnancy treatment at Gansu Provincial Maternity and Child-care Hospital in China were enrolled from 2016 to 2020. Individual's clinical information were studied by cascade XGBoost method to build an intelligent assisted system for predicting the outcome of IVF-ET, called IAS-FET. The cascade XGBoost model was trained using clinical information from 2292 couples and externally tested using clinical information from 573 couples. In addition, several schemes which will be of help for patients to adjust their physical condition to improve their success rate on ART were suggested by IAS-FET.

RESULTS

The outcome of IVF-ET can be predicted by the built IAS-FET method with the area under curve (AUC) value of 0.8759 on the external test set. Besides, this IAS-FET method can provide several schemes to improve the successful rate of IVF-ET outcomes. The built tool for IAS-FET is addressed as a free platform online at http://www.cppdd.cn/ART for the convenient usage of users.

CONCLUSIONS

It suggested the significant influence of personal clinical features for the success of ART. The proposed system IAS-FET based on the top 27 factors could be a promising tool to predict the outcome of ART and propose a plan for the patient's physical adjustment. With the help of IAS-FET, patients can take informed steps towards increasing their chances of a successful outcome on their journey to parenthood.

Use of the RCOG risk assessment model and biomarkers to evaluate the risk of postpartum venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE) is a leading cause of morbidity and mortality during pregnancy and the puerperium. The vast majority of VTE occurs after childbirth. China has not yet established standard risk assessment model for postpartum venous thromboembolism (VTE), the Royal College of Obstetricians and Gynecologists (RCOG) risk assessment model (RAM) is commonly used in clinic at present. Herein, we aimed to evaluate the validity of the RCOG RAM in the Chinese population and try to formulate a local risk assessment model by combining with other biomarkers for VTE prophylaxis.

METHODS

The retrospective study was conducted from January 2019 to December 2021at Shanghai First Maternity and Infant Hospital which has approximately 30,000 births annually, and the incidence of VTE, differences between RCOG-recommended risk factors, and other biological indicators from medical records were evaluated.

RESULTS

The study included VTE (n = 146) and non-VTE(n = 413) women who examined by imaging for suspicion of postpartum VTE. There was no statistical difference in the incidence rate of postpartum VTE between the low-score group (23.8%) and the high-score group (28%) after stratification by RCOG RAM. However, we found that cesarean section (in the low-score group), white blood cell (WBC) ≥ 8.64*10^9/L (in the high-score group), low-density lipoprotein(LDL) ≥ 2.70 mmol/L, and D-dimer ≥ 3.04 mg/L (in both groups) were highly associated with postpartum VTE. Subsequently, the validity of the RCOG RAM combined with biomarkers as a model for the risk assessment of VTE was estimated and the results showed that this model has good accuracy, sensitivity, and specificity.

CONCLUSIONS

Our study indicated that the RCOG RAM was not the best strategy for predicting postpartum VTE. Combined with some biomarkers (including the value of LDL and D-Dimer, and WBC count), the RCOG RAM is more efficient when identifying high-risk groups of postpartum VTE in the Chinese population.

TRIAL REGISTRATION

This purely observational study does not require registration based on ICMJE guidelines.

Clinical and laboratory characteristics of COVID-19 in pregnant women

This article discusses the distinct characteristics of COVID-19 in pregnant women and investigates potential early predictors of disease severity in this specific patient population. The study included 116 pregnant women with a confirmed diagnosis of COVID-19 in different trimesters of pregnancy. In addition to clinical features, we evaluated general clinical research methods, biochemical parameters (procalcitonin, C-reactive protein, D-dimer), and the leukocyte index of endogenous intoxication and lymphocytic index to identify potential early predictors of disease severity. All pregnant women were divided into two study groups: Group I - pregnant women with mild course, and Group II - pregnant women with moderate and severe course of COVID-19. Most pregnant women (72.4%) experienced a non-severe course characterized by catarrhal symptoms and moderate intoxication. However, pulmonary manifestations and pregnancy-related complications were detected in pregnant women from Group 2. The levels of C-reactive protein and procalcitonin in both study groups were significantly increased compared to the control group. In pregnant women with moderate and severe COVID-19, indicators of endogenous intoxication were significantly pronounced. Establishing associations between leukocyte indices and biomarkers, such as procalcitonin and C-reactive protein, enables the utilization of routine complete blood counts as a primary screening tool for predicting the severity of COVID-19 in pregnant women.

Trajectories of maternal D-dimer are associated with the risk of developing adverse maternal and perinatal outcomes: a prospective birth cohort study

OBJECTIVE

To assess the relationships of maternal D-dimer trajectories with the risk of developing adverse maternal and perinatal outcomes (AMPOs).

METHODS

A prospective birth cohort study was conducted in China, and 7,095 women who had singleton birth were included. The latent class growth model was used to determine the maternal D-dimer trajectory.

RESULTS

Three maternal D-dimer trajectories were identified: (1) slight increase (43.6%), (2) rapid rise (51.3%), (3) sustained high (5.1%). Compared to pregnant women with a slight increase in D-dimer trajectory, the risk of gestational diabetes mellitus, placenta previa, macrosomia, large for gestational age (LGA), and increased postpartum bleeding was significantly increased in those with a rapid rise trajectory (adjusted OR=1.22, 2.00, 1.80, and 1.56, adjusted β=15.92∼25.1ml, respectively, P<0.05), and women with a sustained high trajectory also demonstrated a relatively elevated risk of macrosomia and LGA (adjusted OR=2.11 and 1.82, respectively, P<0.05). While the odds of pregnancy-induced hypertension, low birth weight, and small for gestational age in pregnant women with the rapid rise D-dimer trajectory and fetal distress in those with sustained high trajectory exhibited a reduction (adjusted OR=0.62, 0.38, 0.54, and 0.64, respectively, P<0.05).

CONCLUSION

This study highlights the influence of inappropriate maternal D-dimer trajectories on the risk of AMPOs.

Pulmonary Embolism After in vitro Fertilization and Cesarean Section: Two Case Reports and Brief Review of the Literature

This paper reports two cases of postpartum pulmonary embolism in Taicang First People's Hospital affiliated to Soochow University. They share many similarities in age, fertilization way, birthing method, incidence of pulmonary embolism, treatment and prognosis. The main purpose is to inspire the current maternal PTE risk assessment, diagnosis and treatment, as well as to explore the existing limitations and problems.

Risk stratification for pregnancy-associated venous thromboembolism: Potential role for global coagulation assays

Risk assessment for venous thromboembolism in pregnancy and the puerperium is currently limited to stratifying clinical surrogate risk factors without high-quality evidence. While the absolute risk of pregnancy-associated venous thromboembolism is low for the vast majority of women, associated morbidity and mortality remains significant. As guidelines for thromboprophylaxis vary widely, some women may be under- or over-anticoagulated, contributing to poor outcomes. New global coagulation assays provide a holistic view of coagulation and may have the potential to detect hypercoagulability in pregnancy, unlike clinically available coagulation assays. However, there are major technical challenges to overcome before global coagulation assays can be realistically proposed as an adjunct to risk assessment for pregnancy-associated venous thromboembolism. This review summarises the literature and controversies in the prediction and prevention of pregnancy-associated venous thromboembolism and outlines the new tools in haematology that may assist in our future understanding of hypercoagulability in pregnancy.

Obstetric venous thromboembolism: Evaluation of prophylactic approach based on risk scores, D-dimer levels, and ultrasonography findings in a tertiary hospital in Japan

AIM

Pulmonary embolism remains a leading cause of maternal mortality in developed countries despite developments in venous thromboembolism prophylaxis strategies. This study aimed to evaluate the effectiveness of our approach involving risk-scoring, D-dimer level assessment, and ultrasonography for obstetric venous thromboembolism.

METHODS

This retrospective cohort study included women who delivered at 22-41 weeks of gestation in The University of Tsukuba Hospital, Japan between January and December 2020. Venous thromboembolism risk (determined according to Japanese guidelines) and D-dimer levels were evaluated within 20 weeks of gestation, 30-34 weeks of gestation, and during the pre-delivery period (36 weeks of gestation or any time before preterm delivery). Compression and color Doppler ultrasonography for lower extremity deep vein thrombosis were performed if D-dimer levels were ≥3.2 μg/mL (for those undergoing cesarean delivery, 1.0 μg/mL).

RESULTS

Of 1026 women, 6 women had deep vein thrombosis during pregnancy and 1 during the puerperium period. Pulmonary embolism was not observed. The D-dimer screening result was positive for 8 women (2%) within 20 weeks of gestation (deep vein thrombosis was confirmed in 3 of them), 87 women (10%) (no deep vein thrombosis) at 30-34 weeks of gestation, and 367 women (36%) during the pre-delivery period (asymptomatic deep vein thrombosis in one). Based on the Japanese guidelines, 1%, 11%, 33%, and 55% of women had high, intermediate, low, and no postpartum risk factors, respectively.

CONCLUSIONS

Our approach appears useful for antenatal venous thromboembolism screening in the first trimester. For postpartum prophylaxis, more cost-effective strategies are needed.

Reference intervals for coagulation parameters in non-pregnant and pregnant women

Established reference intervals (RIs) of coagulation parameters generally based on the general population are not applicable to specific women. In order to accurately evaluate the coagulation status of non-pregnant women and pregnant women, specific RIs should be established. Our study recruited 465 non-pregnant women and 1972 pregnant women aged 20-45 years. Eight tests including antithrombin (AT), protein C (PC), free protein S (fPS), lupus anticoagulant (LA), D-dimer, fibrin/fibrinogen degradation products (FDP), coagulation factor VII (FVII), and factor VIII (FVIII) were performed on ACL TOP automated coagulation instrument. The RIs for these tests were established in non-pregnant and pregnant women at different gestational weeks. Compared to the non-pregnant group, the medians of AT and fPS were lower, while the medians of PC, LA normalized ratio, D-dimer, FDP, FVII, and FVIII were higher. During pregnancy, AT and fPS activity showed a decreasing trend, with the increase of gestational age. PC activity, LA normalized ratio, D-dimer concentrations, FDP concentrations, FVII, and FVIII activity presented an increasing trend, with the increase of gestational age. The non-pregnant women-specific RIs and the gestational age-specific RIs of AT, PC, fPS, LA normalized ratio, D-dimer, FDP, FVII, and FVIII needed to be established for accurate clinical diagnoses.

D-dimer level significance for deep vein thrombosis screening in the third trimester: a retrospective study

Background

Venous thromboembolism often develops after surgery and childbirth, resulting in death in some cases. Although early deep vein thrombosis (DVT) detection can predict pulmonary thromboembolism, there is no early screening method for DVT in pregnant women. Lack of consensus regarding significance or setting and cut-off value interpretation of D-dimer levels further impedes venous thromboembolism screening in pregnant women.

This study aimed to examine the utility of third-trimester serum D-dimer levels as a screening test for DVT during pregnancy and to determine the frequency of asymptomatic DVT using lower-limb compression ultrasonography.

Methods

This single-center retrospective study included 497 pregnant women who underwent elective cesarean section at term in our hospital between January 2013 and December 2019. Serum D-dimer levels were preoperatively measured at 32–37 weeks’ gestation. The presence or absence of DVT in patients with serum D-dimer levels ≥ 3.0 µg/ml, the cut-off value, was examined using compression ultrasonography. In all patients, the presence or absence of clinical venous thrombosis (symptoms such as lower-limb pain, swelling, and heat sensation) was examined within 4 postoperative weeks.

The Royal College of Obstetricians and Gynecologists Guideline 2015 was referred to determine risk factors for the onset of venous thrombosis during pregnancy. Among those, we examined the risk factors for DVT that result in high D-dimer levels during pregnancy.

Results

The median age and body mass index were 35 (20–47) years and 21.2 (16.4–41.1) kg/m², respectively. Further, the median gestational age and D-dimer levels were 37 weeks and 2.1 (0.2–16.0) µg/ml, respectively. Compression ultrasonography was performed on 135 (26.5%) patients with a D-dimer level ≥ 3.0 µg/ml, with none of the patients showing DVT. All patients were followed up for 4 postoperative weeks, with none presenting with venous thromboembolism. Multivariate analysis showed that hypertensive disorders of pregnancy are an independent risk factor for venous thromboembolism that causes high D-dimer levels (odds ratio: 2.48, 95% confidence interval: 1.05–6.50, P = 0.04).

Conclusion

There may be low utility in screening for DVT using D-dimer levels in the third trimester. Further, prepartum asymptomatic DVT has a low frequency, indicating the low utility of compression ultrasonography.

Trial registration

Institutional Review Board of Tottori University Hospital (IRB no. 20A149).

Comparison of guidelines for evaluation of suspected PE in pregnancy: a cost-effectiveness analysis

BACKGROUND

Pulmonary embolism (PE) remains a leading cause of maternal mortality, yet diagnosis remains challenging. International diagnostic guidelines vary significantly in their recommendations, making it difficult to determine an optimal policy for evaluation.

RESEARCH QUESTION

Which societal-level diagnostic guideline for evaluation of suspected PE in pregnancy is an optimal policy in terms of its cost-effectiveness?

STUDY DESIGN AND METHODS

We constructed a complex Markov decision model to evaluate the cost-effectiveness of each identified societal guideline for diagnosis of PE in pregnancy. Our model accounted for risk stratification, empiric treatment, diagnostic testing strategies, as well as short- and long-term effects from PE, treatment with low-molecular weight heparin, and radiation exposure from advanced imaging. We considered clinical and cost outcomes of each guideline from a U.S. health care system perspective with a lifetime horizon. Clinical effectiveness and costs were measured in time-discounted quality-adjusted life years (QALYs) and U.S. dollars respectively. Strategies were compared using the incremental cost-effectiveness ratio (ICER) with a willingness-to-pay threshold of $100,000 per QALY. One-way, multi-way, and probabilistic sensitivity analyses were performed.

RESULTS

We identified six international societal-level guidelines. Base-case analysis showed the guideline proposed by the American Thoracic Society-Society of Thoracic Radiology (ATS-STR) yielded the highest health benefits (22.90 QALYs) and was cost-effective, with an ICER of $7,808 over the guideline proposed by the Australian Society of Thrombosis and Haemostasis and the Society of Obstetric Medicine of Australia and New Zealand (ASTH-SOMANZ). All remaining guidelines were dominated. The ATS-STR guideline-recommended strategy yielded an expected additional 2.7 QALYs per 100 patients evaluated over the ASTH-SOMANZ. Conclusions were robust to sensitivity analyses, with the ATS-STR guideline optimal in 86% of probabilistic sensitivity analysis scenarios.

INTERPRETATION

The ATS-STR guideline for diagnosis of suspected PE in pregnancy is cost-effective and generates better expected health outcomes than guidelines proposed by other medical societies.

Predictive value of D-dimer and analysis of risk factors in pregnant women with suspected pulmonary embolism after cesarean section

Background

Acute pulmonary embolism (PE) is one of the leading causes of maternal mortality, and cesarean section is an established independent risk factor for PE. The diagnostic utility of D-dimer for PE in non-pregnant women has been well-established, but its role in women with suspected PE after cesarean section is unclear. Furthermore, the optimal threshold level in this patient population is unknown. Traditional D-dimer levels have low diagnostic specificity, resulting in many pregnant women being exposed to potentially harmful radiation despite negative diagnostic imaging results. This research aimed to optimize the clinical threshold for D-dimer to improve specificity while ensuring high sensitivity and to identify risk factors for PE after cesarean section.

Methods

This retrospective study of 289 women who underwent diagnostic imaging (ventilation/perfusion [V/Q] or computed tomographic pulmonary angiography [CTPA]) for suspected acute PE after cesarean delivery from 2010 to 2021 was conducted. Clinical data and laboratory indicators within 24 h postpartum including D-dimer levels were collected for analyses.

Results

The final analysis included 125 patients, among whom 33 were diagnosed with acute PE (incidence of 11.42%, 95% confidence interval 7.7–15.1). The receiver operating characteristic curve analysis suggested that a D-dimer cut-off value of 800 ng/mL had specificity of 25.26% and sensitivity of 100% for detecting PE. The cut-off value was adjusted to 1000 ng/mL with a specificity of 34.74% and a sensitivity of 96.67%. Using a D-dimer cut-off value of 800 ng/mL (instead of the conventional value of 500 ng/mL) increased the number of patients excluded from suspected PE from 9.6 to 18.4% without additional false-negative results. Of note, a history of known thrombophilia was significantly more common in patients with PE than in those without (P < 0.05). No other independent risk factors were noted in our study.

Conclusions

The D-dimer cut-off value of 800 ng/mL ensures high sensitivity and increases specificity compared to the conventional threshold of 500 ng/mL. Utilizing this higher threshold can reduce the number of unnecessary CT and subsequently unnecessary radiation exposure, in women after cesarean delivery. Prospective studies should also be conducted to verify these results.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01757-3.

A Comprehensive Review of the Management of Pregnant Women with COVID-19: Useful Information for Obstetricians

Due to the physiological changes of the cardiovascular system and respiratory system in pregnancy, pregnant women are vulnerable to pathogen infection and severe pneumonia. With the increasing incidence of COVID-19 pneumonia, its influence on pregnant women and neonates has attracted more attention. In this review, we collected all relevant articles published in English from September 1, 2019 to June 10, 2021, regarding the epidemiology, clinical presentations, chemical examinations, imaging findings, the timing of delivery and delivery mode, maternal and neonatal complications, medication, and vertical transmission of COVID-19 in pregnancy. It has been reported that compared with non-pregnant females, pregnant women with COVID-19 are more likely to develop into severe type. In particular, the risk of entering the intensive care unit and endotracheal intubation was higher. Chest computed tomography and blood routine examination are useful for the diagnosis of COVID-19 in a short period of time. COVID-19 pneumonia is not an independent indication for terminating the pregnancy, and it is not contraindicated for vaginal delivery. Compared to normal pregnant females, patients with COVID-19 showed an elevated susceptibility of preterm delivery. Multidisciplinary consultation was suggested in the treatment policy of COVID-19 in pregnancy. Currently, there is no evaluation on the safety, efficacy, and immunity of the approved vaccines for mothers and infants. In human placental tissues, the COVID-19 virus has been found by different detection methods. The mechanism by which the virus enters the placental tissue is unclear, which may be related to placental inflammation. The long-term prognosis of pregnant women with COVID-19 remains unclear and requires further detailed investigation.

New cut-off point for D-dimer in the diagnosis of pulmonary embolism during pregnancy

Background

Considering that pulmonary embolism (PE) is one of the leading causes of mortality among pregnant women and that the D-dimer level in pregnancy can be highly fluctuating, a new and reliable D-dimer reference value is essential to identifying PE in this group of patients. Hence, the present study aimed to evaluate the diagnostic effect of D-dimer testing in pregnant women with suspected PE.

Methods

This study recruited 100 women with confirmed pregnancy or six weeks after delivery or abortion with suspected PE symptoms. Wells criteria, D-dimer values, and pregnancy trimesters were recorded. Definitive PE results were obtained using multidetector computed tomography (MDCT) or pulmonary ventilation/perfusion scans.

Results

D-dimer cut-off point in PE diagnosis was higher than 1,447 mg/L [sensitivity, 87.5%; specificity, 63.04%; area under the curve (AUC)=0.735; P=0.003]. In addition, the combination of Wells criteria with the D-dimer test indicated that the cut-off points of D-dimer in PE likely and unlikely women were 1,962 and 1,447 mg/L, respectively, and had acceptable and significant diagnostic value in PE detection. In addition, the diagnostic value of D-dimer in pregnancy trimesters was not found to be significant (P>0.05).

Conclusion

The new cut-off points of 1,447 and 1,962 mg/L were determined for D-dimer in pregnant women with likely and unlikely PE, respectively. Moreover, the new cut-off points in the first and second trimesters of pregnancy were 1,701 mg/L and 1,451 mg/L, respectively, which indicated no statistically acceptable diagnostic value.

The Optimal Cutoff Level of D-Dimer during Pregnancy to Exclude Deep Vein Thrombosis, and the Association between D-Dimer and Postpartum Hemorrhage in Cesarean Section Patients

OBJECTIVE

The main purpose was to clarify the optimal D-dimer cutoff level during pregnancy to exclude deep vein thrombosis (DVT) prior to Cesarean section. The secondary purpose was to determine whether D-dimer can predict severe postpartum hemorrhage (PPH) in Cesarean section patients.

METHODS

Two hundred and seventy eight elective Cesarean section cases were enrolled. Clinical factors and blood parameters at 34-37 weeks of gestation were analyzed. To detect DVT, lower extremities veins were examined using color Doppler ultrasonography in cases with D-dimer level ≥ 1.5 μg/mL. In addition, postpartum blood loss amounts during Cesarean section were recorded.

RESULTS

Five DVT cases occurred in 250 singleton pregnancies, and 2 DVT cases occurred in 28 twin pregnancies. The overall incidence of DVT was 2.5%. The D-dimer level was higher in DVT cases than in non-DVT cases (3.84±1.97 vs. 2.31±1.48 μg/mL, P<0.01). The optimal D-dimer cutoff level was 2.6 μg/mL with a negative predic tive value of 99.5%, and sensitivity of 85.7%. PPH during Cesarean section was positively correlated with D-dimer level in all pregnancies. However, this relationship disappeared after excluding twin pregnancies.

CONCLUSION

A D-dimer level < 2.6 μg/mL at 34-37 weeks of gestation has the potential to exclude DVT. D-dimer can be an independent predictor for severe PPH for all Cesarean section cases, including twin pregnancies.

COVID-19 and Pregnancy: Risk, Symptoms, Diagnosis, and Treatment

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a novel virus responsible for causing an infection known as COVID-19. Several pulmonary and systemic manifestations of the illness have been described since the discovery of this virus. However, there have been higher-risk populations in which this infection has not been well studied nor documented. One of these populations includes the pregnant cohort. The purpose of this article is to describe the clinical manifestations of COVID-19 infection in the pregnant population and review the implications and sequelae of the infection throughout pregnancy and outcomes of live births. Also, we summarize the understanding and safety of current treatments and vaccination in pregnancy. This comprehensive review article comprises several case reports, case series, cohort studies, retrospective studies, and randomized clinical trials. Findings regarding maternal morbidity included an increased risk of acquiring severe COVID-19 infection requiring a higher level of inpatient hospital care along with an increased risk of preterm labor and cesarean delivery. Neonatal COVID-19 vertical transmission was shown to have conflicting data as there was a presence of transmission in certain retrospective studies and absence in others. There was also no evidence of teratogenicity from maternal COVID-19 infection. In conclusion, in part due to the unique physiologic state of pregnancy and part due to unknown factors, pregnant patients are at increased risk for negative outcomes of COVID-19 infection and must be classified as a high-risk population.

Severe coronavirus disease pneumonia in a pregnant woman at 25 weeks' gestation: A case report

There are numerous reports on the effects of the coronavirus disease on mothers and fetuses during pregnancy. It is currently unknown whether pregnancy is associated with a high risk of severe coronavirus disease. We report a pregnant patient with coronavirus disease who underwent a cesarean section. A pregnant 39-year-old Japanese woman was diagnosed with coronavirus disease at 25 weeks of gestation. Her breathing condition worsened daily, and she required oxygen administration. On day 6 of her 26th week of gestation, she developed severe pneumonia and required tracheal intubation and artificial ventilation, and an emergency cesarean section was performed under general anesthesia. It is necessary to investigate the risk of increased coronavirus disease severity during pregnancy, the effects of coronavirus disease on perinatal prognosis, and the management of pregnancy with coronavirus disease.

The clinical utility of D-dimer/platelet count ratio in pregnant women

OBJECTIVE

We performed a retrospective study to assess the clinical utility of a new index, D-dimer/platelet count (DD/PLT) ratio, in discriminating preeclampsia from normal pregnancy and gestational hypertension during third trimester, compared to the biomarkers currently used, such as D-dimer (DD), platelet (PLT), lymphocyte (LIN) and neutrophil (NEU) counts, fibrinogen (FIB), PLT/NEU, NEU/LIN and PLT/LIN ratios.

STUDY DESIGN

We retrospectively included 213 subjects. Of them, 163 and 50 were singleton pregnant and healthy non-pregnant women, respectively. Among pregnant women, 105 had normal pregnancy, 33 had gestational hypertension, and 25 had preeclampsia.

RESULTS

Using Receiver Operating Curve (ROC) analysis, DD/PLT ratio showed significant higher area under the curve (AUC) (0.90; 95% confidence interval (CI) 0.84-0.95) in discriminating preeclampsia from normal pregnancy compared to those of DD, NEU, FIB, LIN, PLT/NEU, NEU/LIN and PLT/LIN ratios (p < .03). In discriminating preeclampsia from gestational hypertension, the DD/PLT AUC (0.90; 95% CI 0.79-0.96) was significantly higher than those of DD, NEU, FIB, LIN, NEU/LIN and PLT/LIN ratios (p < .03), and not statistically different from those of PLT (p = .22) and PLT/NEU ratio (p = .46).

CONCLUSIONS

This study shows that DD/PLT ratio helps to discriminate preeclampsia from normal pregnancy and gestational hypertension. Large-scale studies are needed to verify its clinical usefulness, and to suggest more appropriate cutoff values for a widespread use.

The Predictive Value of d-Dimer Test for Venous Thromboembolism During Puerperium: A Prospective Cohort Study

The aim of this study was to investigate the d-dimer for prediction of venous thromboembolism (VTE) events in puerperium and to identify other risk factors associated with the occurrence of VTE. This was a prospective observational cohort study, which included 16 127 women who gave birth after 28 weeks of gestation at Women’s Hospital of Zhejiang University, School of Medicine, from January 2016 to December 2016. Data including basic maternal and fetal characteristics, pregnancy complications, and predictive biomarkers within postpartum 24 hours including d-dimer, platelet, and fibrinogen were collected for analyses. In the cohort study, 19 (0.12%) women were identified as VTE, including 1 pulmonary embolism event and 18 deep venous thrombosis events. The receiver operating characteristic curve analysis suggested the best cutoff point for d-dimer level within postpartum 24 hours was 3.695 mg/L, with a specificity of 75.5% and a sensitivity of 73.7%, and there was no statistical correlation between fibrinogen and VTE, as well as between platelets and VTE. On multivariate analysis, age ≥35 years (odds ratio [OR] = 2.895, 95% confidence interval [CI]: 1.079-7.773), scarred uterus (OR = 3.894, 95% CI: 1.234-12.282), intrauterine infection (OR = 7.214, 95% CI: 1.519-34.262), antiphospholipid syndrome (OR = 199.530, 95% CI: 15.152-2627.529), d-dimer ≥3.70 mg/L (OR = 7.573, 95% CI: 2.699-21.247), and emergency cesarean delivery (OR = 23.357, 95% CI: 2.819-193.508) were independently associated with VTE in puerperium. We concluded that d-dimer ≥3.70 mg/L was an independent predictor of VTE during puerperium and d-dimer testing was necessary for perinatal women.

The predictive value of D-dimer test for venous thromboembolism during puerperium in women age 35 or older: a prospective cohort study

Background

This study aimed to investigate the predictive value of the D-dimer level for venous thromboembolism (VTE) events during puerperium of women age at 35 years or older, as well as to identify other risk factors associated with the occurrence of VTE.

Methods

It was a prospective observational cohort study, from January 2014 to December 2018, which involved 12,451 women age 35 or older who delivered at least 28 weeks of gestation at Women’s Hospital of Zhejiang University, School of Medicine. The maternal and fetal demographic characteristics, pregnancy complications, imaging finding and results of laboratory test within postpartum 24 h including D-dimer level, platelet counts and fibrinogen level were collected for analyses.

Results

30(2.4‰) women were identified as VTE, including 1 pulmonary embolism event and 29 deep venous thrombosis events. The receiver operating characteristic (ROC) curve analysis suggested the best cutoff point for D-dimer level within postpartum 24 h of women age 35 or older was 5.545 mg/L, with a specificity of 70.0% and a sensitivity of 75.4%. Besides, there was no statistical correlation between platelet counts and VTE, as well as between fibrinogen level and VTE. On multivariate analysis, D-dimer≥5.50 mg/L (OR = 5.874, 95%CI: 2.678–12.886) and emergency cesarean section (OR = 11.965, 95%CI: 2.732–52.401) were independently associated with VTE in puerperium of women age 35 or older.

Conclusions

We concluded that D-dimer≥5.50 mg/L was an independent predictor of VTE in puerperium with maternal age 35 or older and D-dimer testing was a necessary examination for perinatal women.

COVID-19 Pandemic and Pregnancy in Kidney Disease

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a rapidly spreading pandemic. Owing to changes in the immune system and respiratory physiology, pregnant women are vulnerable to severe viral pneumonia. We review the clinical course, pregnancy outcomes, and management of women with COVID-19 in pregnancy with a focus on those with kidney involvement. Current evidence does not show an increased risk of acquiring SARS-CoV-2 during pregnancy and the maternal course appears to be similar to nonpregnant patients. However, severe maternal disease can lead to complex management challenges and has shown to be associated with higher incidence of preterm and caesarean births. The risk of congenital infection with SARS-CoV-2 is not known. All neonates must be considered as high-risk contacts and should be screened at birth and isolated. Pregnant women should follow all measures to prevent SARS-CoV-2 exposure and this fear should not compromise antenatal care. Use of telemedicine, videoconferencing, and noninvasive fetal and maternal home monitoring devices should be encouraged. High-risk pregnant patients with comorbidities and COVID-19 require hospitalization and close monitoring. Pregnant women with COVID-19 and kidney disease are a high-risk group and should be managed by a multidisciplinary team approach including a nephrologist and neonatologist.

Comparison of the D-dimer concentration in pregnant women with or without pulmonary thromboembolism

Introduction and Objectives:

Pulmonary thromboembolism is the third most common vascular disease after coronary heart disease and stroke and is approximately 10 times more common in pregnant women compared with the nonpregnant population at the same age. The purpose of the current work is to evaluate D-dimer plasma concentration in pregnant women with or without pulmonary thromboembolism.

Methods:

The present study was a cross-sectional study in which 100 pregnant women with suspected pulmonary embolism referred to Imam Khomeini Hospital in Ahwaz in 1398 were studied. After imaging and approving or rejecting a pulmonary embolism, simultaneously the D-dimer sample was taken from them; then the dimer level in each trimester was compared in positive or negative cases of pulmonary embolism. The SPSS software version 22 was used for data analysis.

Results:

The results showed that 12 patients in the study population had pulmonary embolism and 88 patients did not have pulmonary embolism. According to the results of patients with pulmonary embolism based on CT angiography results, there was no significant relationship with increasing gestational age and mean dimer level (P = 0.41). But there was a significant relationship between gestational age and mean dimer level in the group with no pulmonary embolism (P = 0.0001). There was no significant relationship between maternal age and mean dimer level in patients with pulmonary embolism (P = 0.376) and without pulmonary embolism (P = 0.1). Also, there was no significant relationship between the number of pregnancies in both groups with and without pulmonary embolism (P = 0456, P = 0.392).

Conclusion:

Concomitant use of D-dimer and Wells' criteria can help us to diagnose or rule out pulmonary thromboembolism and minimize the risk of pregnant women being exposed to X-rays; given the biodiversity of the D-dimer of every woman during a natural pregnancy, repeated D-dimer measurements in the evaluation of thromboembolic pregnancy during pregnancy have no clinical application.

Elevated levels of D-dimer tested by immunoturbidimetry are associated with the extent of severity of pre-eclampsia

OBJECTIVE

To establish the association between increased levels of D-dimer and severity of pre-eclampsia.

METHODS

A nested, prospective cohort, analytical case-control study was conducted among women with pre-eclampsia between March 2017 and March 2018. Inclusion criteria were age over 18 years, gestational age of more than 20 weeks, a single pregnancy with a living fetus, and a diagnosis of pre-eclampsia. D-dimer was measured by immunoturbidimetry at the time of diagnosis of pre-eclampsia, applying cut-off points adjusted for gestational age. Statistical analysis involved unconditional logistic regression for the association of elevated D-dimer with severe pre-eclampsia adjusted by confounding variables.

RESULTS

There were 132 patients with pre-eclampsia, of which 44 were classed as controls and 88 were classed as having severe pre-eclampsia (case group). Cohort characteristics included: age between 18 and 45 years (mean 28.0 ± 6.3 years); presence of gestational hypertension (10.6%), chronic arterial hypertension (9.0%); and gestational diabetes (5.3%). In the case group, levels of D-dimer were significantly higher than in controls (19.3% vs 2.3%, odds ratio [OR] 10.30, 95% confidence interval [CI] 1.32-80.14, P=0.004) as well as significant in the unconditional logistic regression model adjusted for maternal age, parity, gestational age, and comorbidities (OR 10.02, 95% CI 1.28-78.68, P=0.028).

CONCLUSION

Elevated levels of D-dimer and severe pre-eclampsia are strongly associated, reinforcing evidence that one of the physiopathologic bases of the condition is the activation of fibrinolysis and the coagulation system.

Coronavirus disease 2019 (COVID-19) pandemic and pregnancy

The current coronavirus disease 2019 (COVID-19) pneumonia pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is spreading globally at an accelerated rate, with a basic reproduction number (R0) of 2-2.5, indicating that 2-3 persons will be infected from an index patient. A serious public health emergency, it is particularly deadly in vulnerable populations and communities in which healthcare providers are insufficiently prepared to manage the infection. As of March 16, 2020, there are more than 180,000 confirmed cases of COVID-19 worldwide, with more than 7000 related deaths. The SARS-CoV-2 virus has been isolated from asymptomatic individuals, and affected patients continue to be infectious 2 weeks after cessation of symptoms. The substantial morbidity and socioeconomic impact have necessitated drastic measures across all continents, including nationwide lockdowns and border closures. Pregnant women and their fetuses represent a high-risk population during infectious disease outbreaks. To date, the outcomes of 55 pregnant women infected with COVID-19 and 46 neonates have been reported in the literature, with no definite evidence of vertical transmission. Physiological and mechanical changes in pregnancy increase susceptibility to infections in general, particularly when the cardiorespiratory system is affected, and encourage rapid progression to respiratory failure in the gravida. Furthermore, the pregnancy bias toward T-helper 2 (Th2) system dominance, which protects the fetus, leaves the mother vulnerable to viral infections, which are more effectively contained by the Th1 system. These unique challenges mandate an integrated approach to pregnancies affected by SARS-CoV-2. Here we present a review of COVID-19 in pregnancy, bringing together the various factors integral to the understanding of pathophysiology and susceptibility, diagnostic challenges with real-time reverse transcription polymerase chain reaction (RT-PCR) assays, therapeutic controversies, intrauterine transmission, and maternal-fetal complications. We discuss the latest options in antiviral therapy and vaccine development, including the novel use of chloroquine in the management of COVID-19. Fetal surveillance, in view of the predisposition to growth restriction and special considerations during labor and delivery, is addressed. In addition, we focus on keeping frontline obstetric care providers safe while continuing to provide essential services. Our clinical service model is built around the principles of workplace segregation, responsible social distancing, containment of cross-infection to healthcare providers, judicious use of personal protective equipment, and telemedicine. Our aim is to share a framework that can be adopted by tertiary maternity units managing pregnant women in the flux of a pandemic while maintaining the safety of the patient and healthcare provider at its core.

Reference Values of D-Dimers and Fibrinogen in the Course of Physiological Pregnancy: the Potential Impact of Selected Risk Factors-A Pilot Study

Pregnancy predisposes to thrombotic hemostasis, reflected in the laboratory as, e.g., increased levels of D-Dimers and fibrinogen, but in physiological pregnancy, the risk of venous thrombosis does not increase. Risk may increase if gestational diabetes mellitus (GDM) or nicotinism coexists. Study aims were to determine reference values for D-Dimers and fibrinogen concentrations in each trimester of pregnancy, corrected for GDM and nicotinism. Subjects and Methods. The study involved 71 pregnant women aged 25-44 y. Venous blood was collected three times: in the first (11-14 weeks), second (20-22 weeks), and third (30-31 weeks) trimesters. D-Dimer concentrations were determined by an enzyme-linked fluorescence assay, fibrinogen concentrations by a coagulation method according to Clauss. Results. Significant increases in D-Dimers and fibrinogen concentrations were observed, increasing with successive trimesters (p ANOVA < 0.0001). Furthermore, a positive correlation between D-Dimers and fibrinogen was detected in the second trimester of pregnancy (r = 0.475; p < 0.0001). In addition, a significantly higher fibrinogen concentration was found in women with GDM compared to without GDM (p = 0.0449). Reference ranges for D-Dimers were established, in trimester order, as follows: 167-721 ng/mL, 298-1653 ng/mL, and 483-2256 ng/mL. After adjusting for risk factors, significantly higher D-Dimer values (mainly second and third trimesters) were obtained: 165-638 ng/mL, 282-3474 ng/mL, and 483-4486 ng/mL, respectively. Reference ranges for fibrinogen were, in trimester order, 2.60-6.56 g/L, 3.40-8.53 g/L, and 3.63-9.14 g/L and, after adjustment for risk factors, 3.34-6.73 g/L, 3.40-8.84 g/L, and 3.12-9.91 g/L. Conclusions. We conclude that the increase in D-Dimers and fibrinogen levels in women with physiological pregnancy was compounded by gestational diabetes (GDM) and nicotinism. Therefore, D-Dimers and fibrinogen pregnancy reference values require correction for these risk factors.

Fibrin/fibrinogen degradation products in late pregnancy promote macrosomia prediction in normal uncomplicated pregnancy

OBJECTIVE

The purpose of this study was to explore the association of fibrin/fibrinogen degradation products (FDP) levels with the risk of macrosomia, and determine whether FDP, either alone or combined with traditional factors in late pregnancy, could be used to predict macrosomia at birth in healthy pregnancies.

METHODS

A total of 9464 health pregnant women with singleton pregnancy were recruited in this retrospective cohort study. Maternal plasma FDP levels at hospital admission and birth outcomes were obtained from laboratory system and hospital records, respectively.

RESULTS

FDP levels in late pregnancy were significant higher in women who delivered macrosomia than those who delivered infants with normal weight [median (interquartile range, IQR): 8.2 (5.8-11.9) vs. 6.6 (4.7-9.6) mg/L; P < 0.001]. Multivariable logistic regression analysis demonstrated that FDP levels were independently associated with macrosomia risk. Pregnant women in the highest quartile of FDP had a 2.99-fold higher risk of delivering macrosomia compared with those in the lowest (adjusted OR: 2.99; 95% CI: 2.27-3.93). In addition, the incorporation of FDP into the crude prediction model significantly improved the area under curve (AUC) for predicting macrosomia (0.774 vs. 0.787; P < 0.001).

CONCLUSION

Our findings suggest that maternal plasma FDP levels in late pregnancy are independently and significantly associated with risk of macrosomia. Combination of FDP levels and traditional risk factors could promote the prediction of macrosomia.

Comparison of international societal guidelines for the diagnosis of suspected pulmonary embolism during pregnancy

Pregnancy-associated pulmonary embolism is one of the leading causes of maternal mortality. Diagnosis of pulmonary embolism in pregnancy is challenging, with symptoms of pulmonary embolism mimicking those of pregnancy. Several key components such as clinical prediction tools, risk stratification, laboratory tests, and imaging widely used for diagnosis of pulmonary embolism in the non-pregnant population show limitations for diagnosis in pregnancy. Further, because of the difficulty of studying pregnant patients, high-quality research evaluating the performance of these diagnostic components in pregnancy is scarce. Seven international medical society guidelines present clinical diagnostic pathways for evaluation of pulmonary embolism in pregnancy that show conflicting recommendations on the use of these diagnostic components. This Review assesses all key components of diagnostic clinical pathways recommended by guidelines for evaluation of pulmonary embolism in pregnancy, reviews current evidence, compares the guideline recommendations with respect to each key component, and provides our preferred diagnostic pathway. It provides the guidelines and available data needed for informed decision making to diagnose pulmonary embolism in pregnancy.

Association of maternal D-dimer level in late pregnancy with birth outcomes in a Chinese cohort

OBJECTIVE

To investigate the association of D-dimer level during late pregnancy with birth outcomes in a Chinese population.

METHODS

A retrospective observational cohort study of 11,570 pregnant women who delivered in a single central hospital was conducted. Maternal plasma D-dimer levels at hospital admission and pregnancy outcomes were abstracted and analyzed from laboratory information system and hospital records, respectively.

RESULTS

Maternal plasma D-dimer levels were associated with higher fetal growth indicators for the highest vs. lowest quartile (Q) of D-dimer (mean birth weight: 145.79 g, mean birth length: 0.11 cm, mean gestational age: 0.30 week). Increase in D-dimer quartiles were associated with an decreased risk for small for gestational age (SGA), low birth weight (LBW) and preterm birth (PTB) neonates, and with an increased risk for large for gestational age (LGA), and macrosomia infants (SGA: OR = 0.52, 95% CI: 0.43, 0.64; LBW: OR = 0.58, 95% CI: 0.38, 0.86; PTB: OR = 0.44, 95% CI: 0.35, 0.55; LGA: OR = 2.37, 95% CI: 2.01, 2.78; macrosomia: OR = 2.59, 95% CI, 2.06, 3.24; for Q4 vs. Q1).

CONCLUSION

Maternal plasma D-dimer levels during late pregnancy were associated with birth outcomes and had risk evaluation value for these outcomes.

ACOG Practice Bulletin No. 196: Thromboembolism in Pregnancy

Women who are pregnant or in the postpartum period have a fourfold to fivefold increased risk of thromboembolism compared with nonpregnant women (). Approximately 80% of thromboembolic events in pregnancy are venous (), with a prevalence of 0.5-2.0 per 1,000 pregnant women (). Venous thromboembolism (VTE) is one of the leading causes of maternal mortality in the United States, accounting for 9.3% of all maternal deaths ().The prevalence and severity of this condition during pregnancy and the peripartum period warrant special consideration of management and therapy. Such therapy includes the treatment of acute thrombotic events and prophylaxis for those at increased risk of thrombotic events. The purpose of this document is to provide information regarding the risk factors, diagnosis, management, and prevention of thromboembolism, particularly VTE in pregnancy. This Practice Bulletin has been revised to reflect updated guidance regarding screening for thromboembolism risk and management of anticoagulation around the time of delivery.

D-dimer: Preanalytical, analytical, postanalytical variables, and clinical applications

D-dimer is a soluble fibrin degradation product deriving from the plasmin-mediated degradation of cross-linked fibrin. D-dimer can hence be considered a biomarker of activation of coagulation and fibrinolysis, and it is routinely used for ruling out venous thromboembolism (VTE). D-dimer is increasingly used to assess the risk of VTE recurrence and to help define the optimal duration of anticoagulation treatment in patients with VTE, for diagnosing disseminated intravascular coagulation, and for screening medical patients at increased risk of VTE. This review is aimed at (1) revising the definition of D-dimer; (2) discussing preanalytical variables affecting the measurement of D-dimer; (3) reviewing and comparing assay performance and some postanalytical variables (e.g. different units and age-adjusted cutoffs); and (4) discussing the use of D-dimer measurement across different clinical settings.

Variations of plasma D-dimer level at various points of normal pregnancy and its trends in complicated pregnancies: A retrospective observational cohort study

D-Dimer (DD) is the smallest fragment of plasmin-mediated cleavage of fibrin. There is a progressive increase in DD concentration with advancing gestation in normal pregnancies, making the upper limit of 0.5 μg/ml used in non-pregnant population an unfavorable marker during pregnancy. Coagulation and fibrinolysis parameters are also markedly disturbed in pregnancies complicated by various pathologies.We designed this retrospective observational cohort study to investigate the trimester specific reference range for DD throughout normal pregnancy, and to compare the distribution of DD in third trimester healthy pregnancies and those complicated by preeclampsia (PE), severe preeclampsia (SPE), gestational diabetes mellitus (GDM), premature rupture of membranes (PROM) and preterm premature rupture of membranes (PPROM). In addition, we aimed to determine the diagnostic value of DD in PE and SPE.In this retrospective observational cohort study, 250 normal and 178 complicated pregnancies were included. Normal pregnancies included 88-first trimester, 101-second trimester and 61-third trimester pregnancies. Complicated pregnancy included 34 PE, 44 SPE, 32 GDM, 33 PROM, and 35 PPROM cases during the third trimester. Predefined exclusion criteria were used.The period of gestation (POG) accounted for 41.9% of the variance in DD, with strong correlation between the POG and DD. The trimester specific reference intervals were computed. The distribution for severe preeclampsia was statistically different compared to other categories in the third trimester. This exceptional distribution led to the generation of a receiver operating characteristic (ROC) curve with an area under curve of 0.828, attesting its possible role in predicting severe preeclampsia.We determined trimester specific reference intervals of DD. The role of DD has been explored, and it may be of diagnostic value in severe preeclampsia.

Selecting pregnant or postpartum women with suspected pulmonary embolism for diagnostic imaging: the DiPEP diagnostic study with decision-analysis modelling

BACKGROUND

Pulmonary embolism (PE) is a leading cause of death in pregnancy and post partum, but the symptoms of PE are common in normal pregnancy. Simple diagnostic tests are needed to select women for diagnostic imaging.

OBJECTIVE

To estimate the accuracy, effectiveness and cost-effectiveness of clinical features, decision rules and biomarkers for selecting pregnant or postpartum women with a suspected PE for imaging.

DESIGN

An expert consensus study to develop new clinical decision rules, a case-control study of women with a diagnosed PE or a suspected PE, a biomarker study of women with a suspected PE or diagnosed deep-vein thrombosis (DVT) and decision-analysis modelling.

SETTING

Emergency departments and consultant-led maternity units.

PARTICIPANTS

Pregnant/postpartum women with a diagnosed PE from any hospital reporting to the UK Obstetric Surveillance System research platform and pregnant/postpartum women with a suspected PE or diagnosed DVT at 11 prospectively recruiting sites.

INTERVENTIONS

Clinical features, decision rules and biomarkers.

MAIN OUTCOME MEASURES

Sensitivity, specificity, area under receiver operating characteristic (AUROC) curve, quality-adjusted life-years (QALYs) and health-care costs.

RESULTS

The primary analysis involved 181 women with PE and 259 women without PE in the case-control study and 18 women with DVT, 18 with PE and 247 women without either in the biomarker study. Most clinical features showed no association with PE. The AUROC curves for the clinical decision rules were as follows: primary consensus, 0.626; sensitive consensus, 0.620; specific consensus, 0.589; PE rule-out criteria, 0.621; simplified Geneva score, 0.579; Wells's PE criteria (permissive), 0.577; and Wells's PE criteria (strict), 0.732. The sensitivities and specificities of the D-dimer measurement were 88.4% and 8.8%, respectively, using a standard threshold, and 69.8% and 32.8%, respectively, using a pregnancy-specific threshold. Previous venous thromboembolism, long-haul travel, multiple pregnancy, oxygen saturation, recent surgery, temperature and PE-related chest radiograph abnormality were predictors of PE on multivariable analysis. We were unable to derive a rule through multivariable analysis or recursive partitioning with adequate accuracy. The AUROC curves for the biomarkers were as follows: activated partial thromboplastin time - 0.669, B-type natriuretic peptide - 0.549, C-reactive protein - 0.542, Clauss fibrinogen - 0.589, enzyme-linked immunosorbent assay D-dimer - 0.668, Innovance D-dimer (Siemens Healthcare Diagnostics Products GmbH, distributed by Sysmex UK Ltd, Milton Keynes, UK) - 0.651, mid-regional pro-atrial natriuretic peptide (MRproANP) - 0.524, prothrombin fragment 1 + 2 - 0.562, plasmin-antiplasmin - 0.639, Prothombin time - 0.613, thrombin generation lag time - 0.702, thrombin generation endogenous potential - 0.559, thrombin generation peak - 0.596, thrombin generation time to peak - 0.655, tissue factor - 0.531 and troponin - 0.597. The repeat analysis excluding women who had received anticoagulation was limited by the small number of women with PE (n = 4). The health economic analysis showed that a strategy of scanning all women with a suspected PE accrued more QALYs and incurred fewer costs than any selective strategy based on a clinical decision rule and was therefore the dominant strategy.

LIMITATIONS

The findings apply specifically to the diagnostic assessment of women with a suspected PE in secondary care.

CONCLUSIONS

Clinical features, decision rules and biomarkers do not accurately, effectively or cost-effectively select pregnant or postpartum women with a suspected PE for diagnostic imaging.

FUTURE WORK

New diagnostic technologies need to be developed to detect PE in pregnancy.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN21245595.

FUNDING DETAILS

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 47. See the NIHR Journals Library website for further project information.

D-dimer during pregnancy: establishing trimester-specific reference intervals

Pregnancy is associated with an increased risk of venous thromboembolism (VTE). D-dimer is a biomarker used as an exclusion criterion of VTE disease, but its usefulness during pregnancy shows limitations because D-dimer levels physiologically increase through pregnancy. The aim of our study was to follow the changes of D-dimer levels and to establish trimester-specific reference intervals during normal pregnancy. This is a longitudinal prospective study in which the reference population finally included 102 healthy pregnant women. Plasma D-dimer levels were measured during the three trimesters of pregnancy, using a latex-based immunoturbidimetric assay. Reference intervals were calculated according to the Clinical and Laboratory Standards Institute recommendations. D-dimer levels increased progressively and significantly through pregnancy and peaked in the third trimester, in which D-dimer levels were above the conventional cut-off point (500 µg/L) in 99% of pregnant women. The following reference intervals were defined: first trimester: 169-1202 µg/L, second trimester: 393-3258 µg/L and third trimester: 551-3333 µg/L. The study provides reference intervals of D-dimer during the pregnancy using latex-based immunoturbidimetry on the ACL 300 TOP automated coagulation analyser. Further prospective studies of pregnant women with clinical suspicion of VTE are needed to validate these results.

Review article: Investigations and the pregnant woman in the emergency department - part 1: Laboratory investigations

Accurate assessment of the pregnant patient in the ED depends on knowledge of physiological changes in pregnancy, and how these changes may impact on pathology tests, appearance on point-of-care ultrasound and electrocardiography. In addition the emergency physician needs to be cognisant of disorders that are unique to or more common in pregnancy. Part 1 of this review addresses potential deviations in laboratory investigation reference intervals resulting from physiological alterations in pregnancy, and the important causes of abnormal laboratory results in pregnancy. Part 2 will address the role of point-of-care ultrasound in pregnancy, physiological changes that may affect interpretation of point-of-care ultrasound, physiological changes in electrocardiography, and the safety of radiological procedures in the pregnant patient.

The diagnostic utility of D-dimer and other clinical variables in pregnant and post-partum patients with suspected acute pulmonary embolism

BACKGROUND

Pulmonary embolism (PE) during pregnancy remains one of the leading causes of maternal morbidity and mortality in the developed world. However, there is a paucity of high-quality evidence resulting in a lack of consensus in managing this group of patients. The aims of the study were to address the diagnostic utility of D-dimer for suspected PE in pregnant and post-partum patients and to identify any clinical presentation variables that are predictors of PE in this group of patients.

METHODS

A retrospective case note review of 152 pregnant and post-partum patients who underwent diagnostic imaging (ventilation/perfusion (V/Q) or computed tomographic pulmonary angiography (CTPA)) for suspected PE at a tertiary teaching hospital from 2007 to 2011 was conducted. The reference range for D-dimer was less than 0.5 mg/L as being normal. The following variables were also assessed in terms of their predictive capability for PE diagnosis in pregnancy: heart rate (HR), mean arterial pressure (MAP), shock index (SI) and A-a gradient.

RESULTS

The application of D-dimer testing for suspected PE in this study population had a sensitivity of 100% (95% CI, 73-100%), specificity of 42% (95% CI, 31-53%) and a likelihood negative ratio of 0. None of the clinical variables were significant predictors of PE according to regression analyses.

CONCLUSIONS

There is supportive evidence that a negative D-dimer result is useful as a means of ruling out PE in pregnant and post-partum patients. However, we need a larger prospective observational study to collaborate the findings.

The DiPEP (Diagnosis of PE in Pregnancy) biomarker study: An observational cohort study augmented with additional cases to determine the diagnostic utility of biomarkers for suspected venous thromboembolism during pregnancy and puerperium

This study aimed to estimate the diagnostic utility of biomarkers for suspected venous thromboembolism (VTE) in pregnancy and the puerperium. Research nurses/midwives collected blood samples from 310 pregnant/postpartum women with suspected pulmonary emboli (PE) and 18 with diagnosed deep vein thrombosis (DVT). VTE was diagnosed using imaging, treatment and adverse outcome data. Primary analysis was limited to women with conclusive imaging (36 with VTE, 247 without). The area under the curve (AUC) for each biomarker was: activated partial thromboplastin time 0·669 (95% confidence interval 0·570-0·768), B-type natriuretic peptide 0·549 (0·453-0·645), C-reactive protein 0·542 (0·445-0·639), Clauss fibrinogen 0·589 (0·476-0·701), D-Dimer (by enzyme-linked immunosorbent assay) 0·668 (0·561-0·776), near-patient D-Dimer 0·651 (0·545-0·758), mid-regional pro-atrial natriuretic peptide 0·524 (0·418-0·630), prothrombin fragment 1 + 2 0·562 (0·462-0·661), plasmin-antiplasmin complexes 0·639 (0·536-0·742), prothombin time 0·613 (0·508-0·718), thrombin generation lag time 0·702 (0·598-0·806), thrombin generation endogenous potential 0·559 (0·437-0·681), thrombin generation peak 0·596 (0·478-0·715), thrombin generation time to peak 0·655 (0·541-0·769), soluble tissue factor 0·531 (0·424-0·638) and serum troponin 0·597 (0·499-0·695). No diagnostically useful threshold for diagnosing or ruling out VTE was identified. In pregnancy and the puerperium, conventional and candidate biomarkers have no utility either for their negative or positive predictive value in the diagnosis of VTE.

Thrombin Generation Biomarkers Decline With Parenteral Anticoagulation-An Overlooked Means of Anticoagulation Monitoring?

Anticoagulation therapy is administered to patients to prevent or stop thrombin generation in vivo. Although plasma tests of in vivo thrombin generation have been available for more than 2 decades, they are not routinely used in clinical trials or practice to monitor anticoagulation therapy. We observed a fall in one such marker, the D-dimer antigen, in patients receiving anticoagulation therapy. We therefore conducted a systematic review of the medical literature to document the change in serum biomarkers of thrombin generation following the initiation of anticoagulation therapy. Using a defined search strategy, we screened PubMed and Embase citations and identified full-length articles published in English. Eighteen articles containing serial changes in 1 of 3 markers of thrombin generation (D-dimer antigen, thrombin–antithrombin complexes, and prothrombin fragment 1+2 antigen levels) in the 14 days following the initiation of anticoagulation were identified. Even though the assays used varied considerably, each of the 3 markers of thrombin generation declined in the initial period of anticoagulation therapy, with changes evident as early as 1 day after beginning therapy. These observations provide a rationale for further exploration of these markers as measures of the adequacy of anticoagulation using classic as well as novel anticoagulants. Particular patient groups that would benefit from additional means of monitoring anticoagulation therapy are discussed.

Deep Venous Thrombosis

Deep venous thrombosis (DVT) is a frequently encountered condition that is often diagnosed and treated in the outpatient setting. Risk stratification is helpful and recommended in the evaluation of DVT. An evidence-based diagnostic approach is discussed here. Once diagnosed, the mainstay of DVT treatment is anticoagulation. The specific type and duration of anticoagulation depend upon the suspected etiology of the venous thromboembolism, as well as risks of bleeding and other patient comorbidities. Both specific details and a standardized approach to this vast treatment landscape are presented.

Guidance for the diagnosis of pulmonary embolism during pregnancy: Consensus and controversies

Pulmonary embolism (PE) is one of the leading causes of maternal mortality despite a low incidence of PE during pregnancy. Several challenges surround the diagnosis of PE in pregnant women and the existing clinical guidelines provide weak recommendations on selecting the appropriate investigations for suspected PE in pregnancy. The purpose of this narrative review is to compare and contrast the recommendations of current clinical guidelines and review the evidence underpinning the recommendations on the evaluation of suspected PE in pregnancy. Consensus and controversies, knowledge gaps and areas requiring further research will be highlighted.

Pitfalls in the diagnostic management of pulmonary embolism in pregnancy

Women are at increased risk of venous thromboembolism (VTE) during pregnancy and VTE remains one of the main causes of maternal mortality in developed countries (Konstantinides SV, et al. Eur Heart J 2014; 35(43):3033-69, 69a-69k). Although an accurate diagnosis of acute pulmonary embolism (PE) in pregnant patients is thus of crucial importance, the diagnostic management of suspected PE is challenging for this specific patient category. As D-dimer levels increase physiologically throughout pregnancy, the optimal D-dimer threshold to rule out PE during pregnancy remains unknown. Available clinical decision rules, such as the Wells score and the revised Geneva rule, have not been evaluated in pregnant patients. Also, although ventilation-perfusion (V-Q) lung scan and computed tomography pulmonary angiography (CTPA) can be used in the pregnant population, both modalities have disadvantages of radiation exposure to both mother and foetus. Because of these uncertainties, clinical guidelines provide contradicting recommendations with weak levels of evidence. In this review, we illustrate these dilemmas and provide practice recommendation for the diagnostic management of suspected PE in pregnancy using two real-life patient cases.

Maternal and pregnancy characteristics affect plasma fibrin monomer complexes and D-dimer reference ranges for venous thromboembolism in pregnancy

BACKGROUND

D-dimers have a high negative predictive value for excluding venous thromboembolism outside of pregnancy but the use in pregnancy remains controversial. A higher cut-off value has been proposed in pregnancy due to a continuous increase across gestation. Fibrin monomer complexes have been considered as an alternative diagnostic tool for exclusion of venous thromboembolism in pregnancy due to their different behavior.

OBJECTIVE

We sought to establish normal values of fibrin monomer complexes and D-dimer as a diagnostic tool for the exclusion of venous thromboembolism in pregnancy and examine the effect of maternal and obstetric factors on these markers.

STUDY DESIGN

Plasma D-dimer and fibrin monomer complexes were measured by quantitative immunoturbidimetry in 2870 women with singleton pregnancies attending their routine first-trimester hospital visit in a prospective screening study for adverse obstetric outcome. Multiple regression analysis was used to determine maternal characteristics and obstetric factors affecting the plasma concentrations and converting these into multiple of the median values after adjusting for significant maternal and obstetric characteristics.

RESULTS

Plasma fibrin monomer complexes increased with maternal weight and were lower in women with a history of cocaine abuse and chronic hypertension. D-dimers increased with gestational age and maternal weight and were higher in sickle cell carriers and in women of African and South Asian racial origin compared to Caucasians.

CONCLUSION

Fibrin monomer complexes and D-dimers are affected by maternal and obstetric characteristics rather than only gestational age. The utility of these fibrin-linked markers as a tool for exclusion of venous thromboembolism in pregnancy might be improved by adjusting for patient-specific characteristics.