LDH (Lactate Dehydrogenase): A Biochemical Marker for the Prediction of Adverse Outcomes in Pre-eclampsia and Eclampsia

Effect of MSX1 on the cellular function of cardiomyocytes

MSX1 (Muscle Segment Homeobox 1) has pleiotropic effects in various tissues, including cardiomyocytes, while the effect of MSX1 on cardiomyocyte cellular function was not well known. In this study, we used AC16 cell culture, real-time fluorescence quantitative PCR (qPCR), protein blotting (Western blot), flow cytometry apoptosis assay and lactate dehydrogenase (LDH) ELISA (Enzyme-Linked Immunosorbnent Assay) to investigate the effect of the MSX1 gene on cardiomyocyte function. The results showed that MSX1 plays a protective role against hypoxia of cardiomyocytes. However, further studies are required to fully understand the role of MSX1 in the regulation of LDH expression in different cell types and under different conditions.

A Comprehensive Review on Serum Lactate Dehydrogenase (LDH) and Uric Acid in Preeclampsia: Implications for Maternal Health and Disease Severity

Preeclampsia, a hypertensive disorder unique to pregnancy, remains a significant cause of maternal and fetal morbidity and mortality worldwide. Serum lactate dehydrogenase (LDH) and uric acid have garnered attention as potential biomarkers in understanding preeclampsia's pathophysiology and clinical management. Elevated LDH and uric acid levels have been associated with disease severity and adverse outcomes, highlighting their potential utility in risk stratification and guiding management strategies. This comprehensive review explores the roles of LDH and uric acid in preeclampsia, summarizing current evidence regarding their diagnostic, prognostic, and therapeutic implications. Future research directions are also discussed, including understanding and validation studies. Integrating LDH and uric acid measurements into routine clinical practice may facilitate early detection and intervention, ultimately improving outcomes for preeclamptic pregnancies. This review underscores the importance of serum biomarkers in enhancing our understanding and managing preeclampsia, aiming to optimize maternal and fetal health.

A Study on Serum Lactate Dehydrogenase and Uric Acid in Preeclampsia and Eclampsia: Can they Predict Adverse Fetomaternal Outcome?

Background

Hypertensive disorders of pregnancy affect 3%-5% of all pregnancies, contributing immensely to maternal morbidity and mortality. According to the WHO, the incidence of deaths due to preeclampsia and eclampsia in developing and developed countries is 2.8% and 0.4%, respectively. Lactate dehydrogenase (LDH) and uric acid are good predictors of disease severity.

Aim

This study aims to determine the fetomaternal outcome in relation to abnormal serum levels of LDH and uric acid.

Materials and Methods

A cross-sectional study was carried out in 1200 patients with preeclampsia and eclampsia at a tertiary care center over 2 years. Patients were divided into - Group A: patients with normal LDH (≤300 IU/L) and uric acid (<6 mg/dl) (n = 300). Group B: patients with abnormal LDH and uric acid (n = 900), who were further divided into mild and severe preeclampsia and eclampsia. Abnormal serum values were stratified into groups for easier comparison. The results were compared in terms of maternal and perinatal outcomes.

Results

The incidence of preeclampsia and eclampsia in our study is 3.14% and 1.57%, respectively. Significant changes in LDH and uric acid were associated with increased severity of the disease (LDH - 1116.94 ± 4.78; uric acid - 9.2 ± 2.89). Higher incidence of maternal and fetal complications was seen with severe preeclampsia and eclampsia with LDH >800 IU/L and uric acid >6 mg/dl.

Conclusion

Standard antenatal follow-up should be carried out for early detection and prevention of preeclampsia, with strict monitoring of serum uric acid level and LDH. This may reduce the maternal and fetal complications due to preeclampsia.

Serum LDH Levels in Normotensive and Preeclamptic-Eclamptic Pregnant Women and Its Correlation With Fetomaternal Outcome

Background One of the most prevalent medical issues observed during pregnancy is hypertension. Hypertensive disorders of pregnancy (HDP) and their consequences affect around 5-10% of all pregnancies globally. Preeclampsia is caused by endothelial dysfunction, which causes widespread endothelial leakage and contributes to potentially fatal consequences, such as eclampsia, placental abruption, disseminated intravascular coagulation (DIC), severe renal failure, pulmonary edema, and hepatocellular necrosis. As a result, looking for predictive markers for at-risk pregnancies that can suggest poor maternal or fetal outcomes is critical. Elevated levels of lactate dehydrogenase (LDH), as a sign of cellular damage and dysfunction, can be utilized as a biochemical marker in pregnancy-induced hypertension (PIH) as it represents the severity of the disease, and the occurrence of problems, and has also been demonstrated to co-relate with fetomaternal outcomes. Methodology A total of 230 singleton pregnant women of 28-40 weeks of gestational age were enrolled in this study. All women were divided into two groups - normotensive and preeclamptic-eclamptic groups; the second group was further divided into mild preeclampsia, severe preeclampsia, and eclampsia, based on blood pressure and the presence of proteinuria. Serum lactate dehydrogenase levels were measured in both groups and correlated with their fetomaternal outcome. Results Mean serum lactate dehydrogenase (LDH) level in eclamptic women was 1515.86 ± 754, in severely preeclamptic women was 932.2 ± 448, mild preeclamptic women were 580.5±213, while in normotensive women mean LDH level was 378.6 ± 124. The difference between normotensive and preeclamptic-eclamptic women was statistically significant (p < 0.001). The complications in the preeclamptic-eclamptic group were increased significantly in women with LDH > 800 IU/L, 600-800 IU/L compared to those who had < 600 IU/L LDH levels. Conclusions Serum LDH levels were significantly higher in women of preeclamptic-eclamptic group compared to the normotensive pregnant women. Higher LDH levels were positively correlated with disease severity and maternal complications like placental abruption, hemolysis elevated liver enzymes low platelet count (HELLP), disseminated intravascular coagulation (DIC), acute renal failure, intracranial hemorrhage, pulmonary edema, and maternal death and for fetal complications like preterm, intrauterine growth restriction (IUGR), APGAR at 1 minute < 7, APGAR at 5 minutes < 7, low birth weight (LBW), neonatal intensive care unit (NICU) admission and intrauterine fetal death (IUFD).

Elevated lactate dehydrogenase predicts poor prognosis of acute ischemic stroke

Background

Lactate dehydrogenase (LDH) is associated with the prognosis of many diseases, but the relationship between LDH and the poor prognosis (recurrence and death) of acute ischemic stroke (AIS) has not been fully clarified. This study aimed to investigate the association between admission LDH level and poor prognosis in patients with AIS.

Methods

This retrospective study enrolled AIS patients treated in Taizhou Hospital of Zhejiang Province from July 2019 to December 2019. Poor prognosis included AIS recurrence and all-cause death at 3, 6, and 18 months. The correction between LDH and poor prognosis or all-cause death was assessed. Lasso Cox expression and multivariate Cox expression analyses were used to evaluate the association of LDH with the risk of poor prognosis and all-cause death, respectively. A nomogram was constructed to evaluate the predictive Values of LDH for the poor prognosis and all-cause death of AIS.

Results

732 patients were included in the study. Multivariate analysis shows that admission LDH levels were significantly correlated with poor prognosis [odds ratio (OR),1.003; 95% confidence interval (95% CI), 1.001–1.005; P = 0.001] and all-cause death (OR, 1.005; 95% CI, 1.000–1.009; P = 0.031). The correlation analysis showed that admission LDH level was positively correlated with National Institutes of Health Stroke Scale (NIHSS) score and modified Rankin Scale (mRS) score. Time-dependent receiver operating characteristic (td-ROC) curves analysis showed that the AUC values of admission LDH level for predicting prognosis of AIS patients in 3-month, 6-month, 12-month and 18-month were 0.706 (95% CI, 0.604–0.810), 0.653 (95% CI, 0.583–0.723), 0.616 (95% CI, 0.556–60676) and 0.610 (95% CI, 0.552–0.680), respectively. And td-ROC also showed that the AUC values of admission LDH level for predicting all-cause death of AIS patients in 3-month, 6-month,12-month and 18-month were 0.861 (95% CI, 0.764–0.958), 0.824 (95% CI, 0.753–0.890), 0.726 (95% CI, 0.633–0.819) and 0.715 (95% CI, 0.622–0.807), respectively. The nomograms were constructed to create the predictive models of the poor prognosis and all-cause death of AIS.

Conclusion

Higher LDH levels are independently associated with poor prognosis and all-cause death of AIS.

Regulatory mechanisms of tetramethylpyrazine on central nervous system diseases: A review

Central nervous system (CNS) diseases can lead to motor, sensory, speech, cognitive dysfunction, and sometimes even death. These diseases are recognized to cause a substantial socio-economic impact on a global scale. Tetramethylpyrazine (TMP) is one of the main active ingredients extracted from the Chinese herbal medicine Ligusticum striatum DC. (Chuan Xiong). Many in vivo and in vitro studies have demonstrated that TMP has a certain role in the treatment of CNS diseases through inhibiting calcium ion overload and glutamate excitotoxicity, anti-oxidative/nitrification stress, mitigating inflammatory response, anti-apoptosis, protecting the integrity of the blood-brain barrier (BBB) and facilitating synaptic plasticity. In this review, we summarize the roles and mechanisms of action of TMP on ischemic cerebrovascular disease, spinal cord injury, Parkinson’s disease, Alzheimer’s disease, cognitive impairments, migraine, and depression. Our review will provide new insights into the clinical applications of TMP and the development of novel therapeutics.

A New Model for the Predicting the Risk of Preeclampsia in Twin Pregnancy

Objective

We aimed to develop an effective nomogram model for predicting the risk of preeclampsia in twin pregnancies.

Methods

The study was a retrospective cohort study of women pregnant with twins who attended antenatal care and labored between January 2015 and December 2020 at the Fujian Maternity and Child Health Hospital, China. We extracted maternal demographic data and clinical characteristics. Then we performed the least absolute shrinkage and selection operator regression combined with clinical significance to screen variables. Thereafter, multivariate logistic regression was used to construct a nomogram that predicted the risk of preeclampsia in twin pregnancies. Finally, the nomogram was validated using C-statistics (C-index) and calibration curves.

Results

A total of 2,469 women with twin pregnancies were included, of whom 325 (13.16%) had preeclampsia. Multivariate logistic regression models revealed that serum creatinine, uric acid, mean platelet volume, high-density lipoprotein, lactate dehydrogenase, fibrinogen, primiparity, pre-pregnancy body mass index, and regular prenatal were independently associated with preeclampsia in twin pregnancies. The constructed predictive model exhibited a good discrimination and predictive ability for preeclampsia in twin pregnancies (concordance index 0.821).

Conclusion

The model for the prediction of preeclampsia in twin pregnancies has high accuracy and specificity. It can be used to assess the risk of preeclampsia in twin pregnancies.

Overexpression of glycolysis markers in placental tissue of pregnant women with chronic venous disease: a histological study

Chronic Venous Disease (CVD) refers to a wide variety of venous disorders being the varicose veins its most common manifestation. It is well-established the link between pregnancy and the risk of suffering CVD, due to hormonal or haematological factors, especially during the third trimester. In the same manner, previous studies have demonstrated the detrimental effect of this condition in the placental tissue of pregnant women, including in the normal physiology and the metabolomic profile of this organ. In this context, the aim of this study was to evaluate the glucose homeostasis in the placental tissue of women presenting CVD. Through immunohistochemistry, we studied the protein expression of the glucose transporter 1 (GLUT-1), Phosphoglycerate kinase 1 (PGK1), aldolase (ALD), Glyceraldehyde-3-phosphate dehydrogenase (GA3PDH) and lactate dehydrogenase (LDH). Our results have reported a significative increase in the expression of GLUT-1, PGK1, ALD, GA3PDH and the isoenzyme LDHA in placentas of women with CVD. This work has proven for the first-time an altered glucose metabolism in the placental tissue of women affected by CVD, what may aid to understand the pathophysiological mechanisms of this condition in more distant organs such as placenta. Furthermore, our research also supports the basis for further studies in the metabolic phenotyping of the human placenta due to CVD, which may be considered during the late pregnancy in these women.

Serum LDH values in hypertensive disorders of pregnancy and their association with maternal and neonatal morbidity: A meta-analysis

BACKGROUND

Serum lactate dehydrogenase has been extensively studied in hypertensive disorders of pregnancy. However, to date, its clinical usefulness in the field remains unknown. The present meta-analysis has been designed to evaluate differences in serum LDH values among patients with hypertensive disorders of pregnancy and to help determine its diagnostic accuracy as well its predictive accuracy in determining adverse pregnancy outcomes.

METHODS

We searched Medline, Scopus, Clinicaltrials.gov, EMBASE, Cochrane Central Register of Controlled Trials CENTRAL and Google Scholar databases from their inception till 18 March 2021. Observational studies that assessed differences in serum LDH levels among women with hypertensive disorders of pregnancy and healthy controls were included. Meta-analysis was performed using Rstudio. Pooled mean differences (MD) were calculated with the Hartung-Knapp-Sidik-Jonkman. Meta-regression analyses, publication bias assessment and Trim and Fill function were also performed. The adequacy of the sample size was evaluated with Trial Sequential Analysis.

RESULTS

Fifty-two articles were included that comprised 5340 women with hypertensive disorders of pregnancy and 2890 healthy controls. The meta-analysis revealed significant differences among patients with preeclampsia (either mild or severe) compared with controls, as well as among patients with mild and severe preeclampsia. Significant asymmetry was noted after examining funnel plots, however, and the trim and fill analysis revealed that differences were significant only among cases with severe preeclampsia and healthy controls. Morbidity outcomes increased with LDH levels >600 IU/L and particularly when these exceeded 800 IU/L. However, confidence and prediction intervals indicated an underpowered sample size for the accurate determination of the odds of developing maternal morbidity.

CONCLUSION

Despite the extensive research in the field of hypertensive disorders of pregnancy, there is still lack of evidence concerning the diagnostic performance of serum LDH in clinical practice; hence, research should expand in this direction to evaluate its clinical utility.

Serum lactate dehydrogenase activities as systems biomarkers for 48 types of human diseases

Most human diseases are systems diseases, and systems biomarkers are better fitted for diagnostic, prognostic, and treatment monitoring purposes. To search for systems biomarker candidates, lactate dehydrogenase (LDH), a housekeeping protein expressed in all living cells, was investigated. To this end, we analyzed the serum LDH activities from 172,933 patients with 48 clinically defined diseases and 9528 healthy individuals. Based on the median values, we found that 46 out of 48 diseases, leading by acute myocardial infarction, had significantly increased (p < 0.001), whereas gout and cerebral ischemia had significantly decreased (p < 0.001) serum LDH activities compared to the healthy control. Remarkably, hepatic encephalopathy and lung fibrosis had the highest AUCs (0.89, 0.80), sensitivities (0.73, 0.56), and specificities (0.90, 0.91) among 48 human diseases. Statistical analysis revealed that over-downregulation of serum LDH activities was associated with blood-related cancers and diseases. LDH activities were potential systems biomarker candidates (AUCs > 0.8) for hepatic encephalopathy and lung fibrosis.

Development of a constant pressure perfused ex vivo model of the equine larynx

Distal axonopathy is seen in a broad range of species including equine patients. In horses, this degenerative disorder of the recurrent laryngeal nerve is described as recurrent laryngeal neuropathy (RLN). The dysfunctional innervation of the cricoarytenoideus dorsalis muscle (CAD) leads to a loss of performance in affected horses. In general, ex vivo models of the larynx are rare and for equine patients, just one short report is available. To allow for testing new therapy approaches in an isolated organ model, we examined equine larynges in a constant pressure perfused setup. In order to check the vitality and functionality of the isolated larynx, the vessels´ reaction to norepinephrine (NE) and sodium nitroprusside (NP) as vasoactive agents was tested. Additionally, the contractility of the CAD was checked via electrical stimulation. To determine the extent of hypoxic alterations, lactate dehydrogenase (LDH) and lactate were measured and an immunofluorescent analysis of hypoxia-inducible factor (HIF-1α), a key transcription factor in hypoxia, was performed. For this, a hypoxia-induced cell culture for HIF-1α was developed. The application of NE led to an expected vasoconstriction while NP caused the expected vasodilation. During a perfusion period of 352 ±20.78 min, LDH values were in the reference range and lactate values slightly exceeded the reference range at the end of the perfusion. HIF-1α nuclear translocation could reliably be detected in the hypoxia-induced cell cultures, but not in sections of the perfused CAD. With the approach presented here, a solid basis for perfusing equine larynges was established and may serve as a tool for further investigations of equine larynx disorders as well as a transferrable model for other species.

Clinical characteristics of mirror syndrome: a retrospective study of 16 cases

The exact prevalence of mirror syndrome remains unclear, and the precise clinical features need to be disclosed. We retrospectively reviewed 85 cases of foetal hydrops from a total of 98,484 deliveries. Of these 16 showed mirror syndrome, while 69 did not. The incidence of mirror syndrome among all deliveries was 0.0162%, while that among patients with foetal hydrops was 23.2%. Maternal symptoms of mirror syndrome included anaemia (n = 15), hypertension (n = 7), proteinuria (n = 8), pulmonary oedema (n = 3), cardiac failure (n = 2) and HELLP syndrome (n = 2). Placental thickness, placental weight and amniotic fluid index were significantly different between the groups. In the mirror syndrome group, uric acid, lactate dehydrogenase, creatinine and D-dimer levels were significantly higher (p < .05), whereas haemoglobin, serum albumin levels, haematocrit value and platelet count were significantly lower (p < .05). Elevated uric acid, lactate dehydrogenase and D-dimer levels may be useful as predictors of mirror syndrome.Impact statementWhat is already known on this subject? As mirror syndrome is uncommon and under-diagnosed, its exact incidence is not yet clear, and most publications are case reports or reviews of case reports.What the results of this study add? The incidence of mirror syndrome among all deliveries was 0.0162%, while that among patients with foetal hydrops was 23.2%. Pregnant women who develop mirror syndrome may show severe complications of pregnancy. Attention should be paid to the further progress of the condition. Placental thickness, placental weight and amniotic fluid index were significantly different between those with mirror syndrome and those without. In the mirror syndrome group, the uric acid, lactate dehydrogenase, creatinine and D-dimer levels were significantly higher (p < .05), whereas haemoglobin level, haematocrit value, platelet count and serum albumin level were significantly lower (p < .05).What the implications are of these findings for clinical practice and/or further research? Mirror syndrome is not rare among patients with foetal hydrops. Elevated uric acid, lactate dehydrogenase and D-dimer levels may be useful as predictors of mirror syndrome.

Risk factors and pregnancy outcomes associated with retinopathy in patients presenting with severe preeclampsia: A retrospective cohort study

The visual system was reported to be affected in over half of patients with preeclampsia (PE), though fundus examination was performed only among patients complaining of visual symptoms. Delayed diagnosis and treatment of PE-related retinopathy may lead to permanent visual impairment. Therefore, we hypothesize that some clinical or laboratory parameters could predict severity of retinal damage.The aim of the study was to explore the risk factors for retinopathy in severe preeclampsia (sPE) and investigate pregnancy outcomes with different degrees of retinopathy.This retrospective cohort study included women with sPE who underwent ophthalmoscopy and delivered after admission to West China Second University Hospital, between June 2013 and December 2016. Clinical and laboratory characteristics were retrieved from medical records. Patients confirmed with retinopathy were followed up with telephones. Multiple logistic regression analysis was performed to identify risk factors of PE-related retinopathy.Five hundred thirty-four patients were included, of which 17.6% having stage-1/2 retinopathy, 14.6% having stage-3/4 retinopathy, and 67.8% having normal retina. Compared with patients without retinopathy, patients with stage 3/4 retinopathy were more likely to have preterm-birth and low-birth-weight babies. Significant risk factors for stage 3/4 retinopathy in sPE included severe hypertension (odds ratio [OR] 2.24, 95% confidence interval [CI]: 1.10-4.56), elevated white blood cell (WBC) counts (OR 1.88, 95% CI: 1.05-3.35), decreased platelet counts (OR 2.12, 95% CI: 1.07-4.48), lactate dehydrogenase (LDH) concentration of >800 IU/L (OR 2.31, 95% CI: 1.05-5.06), low hemoglobin (HGB) concentrations of <110 g/L (OR 3.73, 95% CI: 1.21-11.47), 24-hour proteinuria of 2 to 5 g (OR 6.39, 95% CI: 2.84-14.39), and >5 g (OR 8.66, 95% CI: 3.67-20.44).This study confirms the association between retinopathy and preterm-birth and low-birth weight in sPE. The risk factors for severe PE-related retinopathy, including severe hypertension, platelet and WBC count, HGB and LDH concentration, and proteinuria, are associated with the development of retinopathy. Routine and repeated fundus examination is recommended for maternal monitoring in sPE.

Biochemical tests of placental function versus ultrasound assessment of fetal size for stillbirth and small-for-gestational-age infants

BACKGROUND

Stillbirth affects 2.6 million pregnancies worldwide each year. Whilst the majority of cases occur in low- and middle-income countries, stillbirth remains an important clinical issue for high-income countries (HICs) - with both the UK and the USA reporting rates above the mean for HICs. In HICs, the most frequently reported association with stillbirth is placental dysfunction. Placental dysfunction may be evident clinically as fetal growth restriction (FGR) and small-for-dates infants. It can be caused by placental abruption or hypertensive disorders of pregnancy and many other disorders and factorsPlacental abnormalities are noted in 11% to 65% of stillbirths. Identification of FGA is difficult in utero. Small-for-gestational age (SGA), as assessed after birth, is the most commonly used surrogate measure for this outcome. The degree of SGA is associated with the likelihood of FGR; 30% of infants with a birthweight < 10th centile are thought to be FGR, while 70% of infants with a birthweight < 3rd centile are thought to be FGR. Critically, SGA is the most significant antenatal risk factor for a stillborn infant. Correct identification of SGA infants is associated with a reduction in the perinatal mortality rate. However, currently used tests, such as measurement of symphysis-fundal height, have a low reported sensitivity and specificity for the identification of SGA infants.

OBJECTIVES

The primary objective was to assess and compare the diagnostic accuracy of ultrasound assessment of fetal growth by estimated fetal weight (EFW) and placental biomarkers alone and in any combination used after 24 weeks of pregnancy in the identification of placental dysfunction as evidenced by either stillbirth, or birth of a SGA infant. Secondary objectives were to investigate the effect of clinical and methodological factors on test performance.

SEARCH METHODS

We developed full search strategies with no language or date restrictions. The following sources were searched: MEDLINE, MEDLINE In Process and Embase via Ovid, Cochrane (Wiley) CENTRAL, Science Citation Index (Web of Science), CINAHL (EBSCO) with search strategies adapted for each database as required; ISRCTN Registry, UK Clinical Trials Gateway, WHO International Clinical Trials Portal and ClinicalTrials.gov for ongoing studies; specialist abstract and conference proceeding resources (British Library's ZETOC and Web of Science Conference Proceedings Citation Index). Search last conducted in Ocober 2016.

SELECTION CRITERIA

We included studies of pregnant women of any age with a gestation of at least 24 weeks if relevant outcomes of pregnancy (live birth/stillbirth; SGA infant) were assessed. Studies were included irrespective of whether pregnant women were deemed to be low or high risk for complications or were of mixed populations (low and high risk). Pregnancies complicated by fetal abnormalities and multi-fetal pregnancies were excluded as they have a higher risk of stillbirth from non-placental causes. With regard to biochemical tests, we included assays performed using any technique and at any threshold used to determine test positivity.

DATA COLLECTION AND ANALYSIS

We extracted the numbers of true positive, false positive, false negative, and true negative test results from each study. We assessed risk of bias and applicability using the QUADAS-2 tool. Meta-analyses were performed using the hierarchical summary ROC model to estimate and compare test accuracy.

MAIN RESULTS

We included 91 studies that evaluated seven tests - blood tests for human placental lactogen (hPL), oestriol, placental growth factor (PlGF) and uric acid, ultrasound EFW and placental grading and urinary oestriol - in a total of 175,426 pregnant women, in which 15,471 pregnancies ended in the birth of a small baby and 740 pregnancies which ended in stillbirth. The quality of included studies was variable with most domains at low risk of bias although 59% of studies were deemed to be of unclear risk of bias for the reference standard domain. Fifty-three per cent of studies were of high concern for applicability due to inclusion of only high- or low-risk women.Using all available data for SGA (86 studies; 159,490 pregnancies involving 15,471 SGA infants), there was evidence of a difference in accuracy (P < 0.0001) between the seven tests for detecting pregnancies that are SGA at birth. Ultrasound EFW was the most accurate test for detecting SGA at birth with a diagnostic odds ratio (DOR) of 21.3 (95% CI 13.1 to 34.6); hPL was the most accurate biochemical test with a DOR of 4.78 (95% CI 3.21 to 7.13). In a hypothetical cohort of 1000 pregnant women, at the median specificity of 0.88 and median prevalence of 19%, EFW, hPL, oestriol, urinary oestriol, uric acid, PlGF and placental grading will miss 50 (95% CI 32 to 68), 116 (97 to 133), 124 (108 to 137), 127 (95 to 152), 139 (118 to 154), 144 (118 to 161), and 144 (122 to 161) SGA infants, respectively. For the detection of pregnancies ending in stillbirth (21 studies; 100,687 pregnancies involving 740 stillbirths), in an indirect comparison of the four biochemical tests, PlGF was the most accurate test with a DOR of 49.2 (95% CI 12.7 to 191). In a hypothetical cohort of 1000 pregnant women, at the median specificity of 0.78 and median prevalence of 1.7%, PlGF, hPL, urinary oestriol and uric acid will miss 2 (95% CI 0 to 4), 4 (2 to 8), 6 (6 to 7) and 8 (3 to 13) stillbirths, respectively. No studies assessed the accuracy of ultrasound EFW for detection of pregnancy ending in stillbirth.

AUTHORS' CONCLUSIONS

Biochemical markers of placental dysfunction used alone have insufficient accuracy to identify pregnancies ending in SGA or stillbirth. Studies combining U and placental biomarkers are needed to determine whether this approach improves diagnostic accuracy over the use of ultrasound estimation of fetal size or biochemical markers of placental dysfunction used alone. Many of the studies included in this review were carried out between 1974 and 2016. Studies of placental substances were mostly carried out before 1991 and after 2013; earlier studies may not reflect developments in test technology.

Evaluation of Hemolysis as a Severe Feature of Preeclampsia

Hemolysis predisposes to adverse pregnancy outcomes. Yet, there are limited data on hemolysis in hypertensive disorders of pregnancy other than hemolysis, elevated liver enzymes, and low platelet count syndrome. To evaluate the prevalence and impact of hemolysis in hypertensive disorders of pregnancy, we performed a retrospective cohort study at a single center (October 2013-May 2017), among women screened for hemolysis using lactate dehydrogenase (LDH) levels. We compared LDH levels by hypertensive disorder (chronic hypertension, gestational hypertension, preeclampsia, and preeclampsia with severe features) and evaluated impact on adverse pregnancy outcomes. Data were analyzed by χ² or t test, ANOVA, test of medians, and logistic regression. Among 8645 deliveries, 1188 (13.7%) had a hypertensive disorder. Of these, 812 (68.4%) had LDH measurement before delivery: chronic hypertension (n=152); gestational hypertension (n=209); preeclampsia (n=216); and preeclampsia with severe features (n=235). LDH ≥400 U/L (≥1.6× normal) was more common in preeclampsia with severe features compared with other hypertensive disorders of pregnancy (9.8% versus 2.3%; P<0.001); adjusted odds ratio 4.52 (95% confidence interval, 2.2-9.2; P<0.001). LDH ≥400 U/L was associated with adverse maternal outcomes (41.7% versus 15.3%; P<0.001), adjusted odds ratio 3.05 (95% confidence interval, 1.4-6.7; P=0.006), and adverse neonatal outcomes (eg, preterm birth 59.4% versus 22.5%; P<0.001). We find that elevated LDH levels are associated with adverse maternal and neonatal outcomes in hypertension and preeclampsia, independent of hemolysis, elevated liver enzymes, and low platelet count syndrome. Therefore, elevated LDH levels (≥1.6× normal or ≥400 U/L) may be considered a severe feature of preeclampsia.