New directions in the prediction of pre-eclampsia

Role of Uterine Artery Doppler Ultrasound in Predicting Pre-Eclampsia in High-Risk Women

Background and objective

Pre-eclampsia (PE) is a major cause of maternal morbidity and mortality. The utility of Doppler ultrasonography (U/S) in predicting PE has not been extensively explored. This study aimed to determine the role of Doppler U/S in predicting PE among high-risk women.

Methodology

This was a retrospective observational study conducted at the Department of Obstetrics and Gynecology of Abbasi Shaheed Hospital in Karachi, over a period of one year, from January 2019 till December 2019. A total of 325 women were initially screened for risk factors for PE. Among them, 75 women were eventually found to have risk factors for PE and hence included in the study. Uterine artery Doppler U/S was performed to evaluate uterine artery’s flow velocity waveforms. They were then used to calculate the presence of diastolic notch and resistance index (RI). At each antenatal visit, the risk factors for PE such as BP, proteinuria, and signs and symptoms were noted. Women were labeled to have PE if they developed hypertension (BP >140/90) after 20 weeks of gestation in combination with proteinuria.

Results

Twenty women (28%) had a normal Doppler flow of the uterine arteries. In 54 (72%) women, a unilateral/bilateral RI >0.58 was observed, and 29 women (38.7%) had a bilateral Rl >0.58. Notching of the uterine artery was also observed in 42 (26.7%, unilateral/bilateral) and in 22 (29.3%) bilaterally. Among the 75 women, BP of 140/90 mmHg along with proteinuria was observed in 56 (76.7%) cases, which were hence diagnosed as PE. Based on the cutoff of Rl and notching of the uterine artery, the overall sensitivity, specificity, and positive and negative predictive values (PPV and NPV) of Doppler U/S in predicting PE were 71.4%, 26.3%, 23.8%, and 74.1%, respectively. As far as individual Doppler U/S indices were concerned, RI >0.58 (unilateral/bilateral) was found to be most sensitive (71%), while the presence of uterine artery notch (unilateral/bilateral) was most specific in predicting PE.

Conclusion

Abnormal Doppler U/S has good overall sensitivity in predicting PE. Among individual Doppler indices, notching of uterine arteries had a better specificity compared to high RI.

Diagnostic value of doppler ultrasound indices of maternal renal interlobar vasculature in the prediction of preeclampsia

We aimed to determine the diagnostic accuracy of maternal renal vasculature Doppler ultrasound indices in the prediction of preeclampsia. A total of 40 pregnant women with a gestational age of more than 20 weeks were included and followed. The pregnant women underwent a Doppler ultrasound examination to measure the resistance index (RI) of the interlobar arteries of right and left kidneys and the renal interlobar vein impedance index (RIVI). Of the included women, 15 patients developed preeclampsia based on clinical and laboratory criteria. The renal vascular Doppler ultrasound indices were compared between the two groups. Then, using the Receiver Operating Characteristic (ROC) analysis, the diagnostic accuracy of interlobar artery RI and RIVI were investigated in the prediction of preeclampsia occurrence. RIVI values of right and left kidneys were significantly higher in the preeclampsia group compared to the normal pregnancy group. The left kidney interlobar artery RI at a cut-point of 0.59 had a sensitivity of 100% and a specificity of 40% (area under curve=0.7, P-0.03) in the prediction of preeclampsia. The RIVI of the left kidney (adjusted odds ratio=17.14, 95% CI = 3.46 to 47.28) was statistically significant in predicting preeclampsia (P-0.006). We found that, besides other routine methods, using Doppler ultrasound and measuring RIVI can be reliable in the prediction of preeclampsia.

Molecular Targets of Aspirin and Prevention of Preeclampsia and Their Potential Association with Circulating Extracellular Vesicles during Pregnancy

Uncomplicated healthy pregnancy is the outcome of successful fertilization, implantation of embryos, trophoblast development and adequate placentation. Any deviation in these cascades of events may lead to complicated pregnancies such as preeclampsia (PE). The current incidence of PE is 2–8% in all pregnancies worldwide, leading to high maternal as well as perinatal mortality and morbidity rates. A number of randomized controlled clinical trials observed the association between low dose aspirin (LDA) treatment in early gestational age and significant reduction of early onset of PE in high-risk pregnant women. However, a substantial knowledge gap exists in identifying the particular mechanism of action of aspirin on placental function. It is already established that the placental-derived exosomes (PdE) are present in the maternal circulation from 6 weeks of gestation, and exosomes contain bioactive molecules such as proteins, lipids and RNA that are a “fingerprint” of their originating cells. Interestingly, levels of exosomes are higher in PE compared to normal pregnancies, and changes in the level of PdE during the first trimester may be used to classify women at risk for developing PE. The aim of this review is to discuss the mechanisms of action of LDA on placental and maternal physiological systems including the role of PdE in these phenomena. This review article will contribute to the in-depth understanding of LDA-induced PE prevention.

Women's experiences of preeclampsia: a prospective survey of preeclamptic women at a single tertiary centre

Preeclampsia (PE) can suddenly disrupt a normal pregnancy experience. This project aimed to see how PE was experienced close to the time of birth, in a group of hospital patients. Women with PE who gave birth at The Royal Women's Hospital, Melbourne, Australia, from October 2010 to May 2012 were asked to complete a survey designed with consumer input. There was a 74% response rate. Regarding diagnosis, 90% experienced PE, 2.5% experienced eclampsia and 7.5% experienced HELLP. For 60% of women, their baby was born earlier than expected. Although 67.5% of women knew little about PE prior to pregnancy and diagnosis, 67.5% believed PE was serious or life threatening. Fifty-five percent were afraid that their baby might die. The women in the study identified the need to obtain more information about PE (97.5%), and 60% indicated that their PE experience would either delay or contribute to the decision to not undertake a future pregnancy. This project details that PE can have a substantial psychological effect on patients around the time of birth. Maternity caregivers can direct counselling to address the specific vulnerabilities raised in PE and thus improve the care of women with PE.Impact StatementWhat is already known on this subject? Qualitative research from New Zealand showed that women experiencing preeclampsia (PE) can have a number of psychological issues with their pregnancy experience, including feeling no longer in control of their pregnancy, dealing with an unexpected medicalised preterm birth, and feeling fear for themselves and their baby's life, even if no formal psychiatric issues are identified. A PE support group surveyed their own members and found that these psychological issues are present in most of their members who had PE.What the results of this study add? This study was a survey of 40 women experiencing PE around the time of birth in a tertiary hospital in Melbourne, Australia, to see if these themes could be applied to a general hospital group. There was a 74% response rate. For 60% of women, the baby was born earlier than expected. Although most women knew little about PE prior to diagnosis, 67.5% believed PE was serious or life threatening at diagnosis. More than half (55%) were afraid their baby might die and 47.5% of women identified that separation from their baby impaired their ability to bond. Most women planned to obtain more information about PE (97.5%) and 50% indicated that their PE experience meant they would either delay or not undertake future pregnancy.What the implications are of these findings for clinical practice and/or further clinical research? This study demonstrates the significance of psychological factors in the care of women with pre-eclampsia or eclampsia and offers a range of issues that the health care provider can use in discussions with women in the early postnatal period, in the inter-pregnancy interval and in subsequent pregnancies. Further research would ideally involve a large sample in a range of hospital settings (primary through tertiary) to further consider the prevalence and enduring nature of themes identified in the present study.

Incidence and risk factors for Preeclampsia in a cohort of healthy nulliparous pregnant women: a nested case-control study

The objective of this study is to determine the incidence, socio-demographic and clinical risk factors for preeclampsia and associated maternal and perinatal adverse outcomes. This is a nested case-control derived from the multicentre cohort study Preterm SAMBA, in five different centres in Brazil, with nulliparous healthy pregnant women. Clinical data were prospectively collected, and risk factors were assessed comparatively between PE cases and controls using risk ratio (RR) (95% CI) plus multivariate analysis. Complete data were available for 1,165 participants. The incidence of preeclampsia was 7.5%. Body mass index determined at the first medical visit and diastolic blood pressure over 75 mmHg at 20 weeks of gestation were independently associated with the occurrence of preeclampsia. Women with preeclampsia sustained a higher incidence of adverse maternal outcomes, including C-section (3.5 fold), preterm birth below 34 weeks of gestation (3.9 fold) and hospital stay longer than 5 days (5.8 fold) than controls. They also had worse perinatal outcomes, including lower birthweight (a mean 379 g lower), small for gestational age babies (RR 2.45 [1.52-3.95]), 5-minute Apgar score less than 7 (RR 2.11 [1.03-4.29]), NICU admission (RR 3.34 [1.61-6.9]) and Neonatal Near Miss (3.65 [1.78-7.49]). Weight gain rate per week, obesity and diastolic blood pressure equal to or higher than 75 mmHg at 20 weeks of gestation were shown to be associated with preeclampsia. Preeclampsia also led to a higher number of C-sections and prolonged hospital admission, in addition to worse neonatal outcomes.

An analysis of the risk factors of preeclampsia and prediction based on combined biochemical indexes

This study aims to investigate the risk factors and the joint biochemical indicators predictive value for preeclampsia. Related factors and biochemical indicators were investigated in 558 patients with preeclampsia and 435 normal pregnant women. Multiplicity analysis was performed by logistic regression. The predictive value of the biochemical index and joint biochemical indicators for predicting the incidence of pregnant women preeclampsia were analyzed by ROC curve. A progestation BMI of >24 kg/m² (OR = 5.412, 95% CI: 1.169-9.447), hypertension history (OR = 7.487, 95% CI: 2.541-11.247) and advanced age (>35 years old, OR = 6.321, 95% CI: 3.142-20.342) are risk factors for preeclampsia. Tumor necrosis factor-α and plasma protein-A are valuable for preeclampsia prediction. The predictive success of preeclampsia could be improved by clinical risk factors associated with biochemical indicators detection.

Increased expression of NLRP3 inflammasome in placentas from pregnant women with severe preeclampsia

Preeclampsia is a pregnancy disorder characterized by imbalance between pro- and anti-inflammatory cytokines associated with high plasma levels of uric acid and Interleukin-1 beta (IL-1β). The inflammasome is a protein complex that mediates innate immune responses via caspase-1 activation promoting secretion of IL-1β and IL-18 in their active forms, and also release of the high-mobility group box 1 protein (HMGB1). As the placenta seems to play an important role in the pathogenesis of PE, the present study investigated the expression of genes and proteins related to the inflammasome in placentas from pregnant women with severe preeclampsia. Placental tissue was collected from 20 normotensive pregnant women and 20 preeclamptic women, and inflammasome components, NLRP3 (NOD-like receptor family, pyrin domain-containing protein 3), caspase-1, IL-1β and IL-18, as well as tumor necrosis factor-alpha (TNF-α) and HMGB1 were evaluated by immunohistochemistry, enzyme-linked immunosorbent assay (ELISA) and also quantified by reverse transcription-qPCR (RT-qPCR). Compared with normotensive pregnant women, placenta from women with PE showed a significant increase in NLRP3, caspase-1, IL-1β, TNF-α and HMGB1 mRNA. Immunohistochemical staining of NLRP3, caspase-1, IL-1β and TNF-α in placental villi, as well as the levels of caspase-1, IL-1β, TNF-α and HMGB1 in placental homogenate were significantly higher in the preeclamptic group than in the normotensive group. However, mRNA expression of IL-18 and its protein concentrations were lower in placentas from preeclamptic women. The results suggest that placentas from pregnant women with preeclampsia show higher expression of NLRP3 inflammasome, which may be involved in the exaggerated inflammatory state in preeclampsia.

First-Trimester Uterine Artery Pulsatility Index and Maternal Serum PAPP-A and PlGF in Prediction of Preeclampsia in Primigravida

Background

Preeclampsia is a heterogeneous disorder affecting different body systems and frequently associated with morbidity and mortality. Early preeclampsia prediction will reduce this associated morbidity and mortality as it will give the chance for frequent maternal and fetal surveillance and application of prophylactic procedures.

Objective

The aim of this work is to evaluate the role of mean pulsatility index (PI) of the uterine arteries and maternal serum concentrations of pregnancy-associated plasma protein A (PAPP-A) and placental growth factor (PlGF) in early preeclampsia prediction in primigravida.

Patients and Methods

Three hundred primigravida attending the antenatal care clinic in Zagazig University Hospitals were included in the study. The mean PI of the uterine arteries was calculated. Maternal serum levels of PAPP-A and PIGF were analyzed by specific immunoassay.

Results

Three hundred women were included in the final analysis, of them 30 patients (10%) suffered from preeclampsia. There was a significant difference between preeclamptic and normal women as regards the mean PI of the uterine arteries and levels of PAPP-A and PIGF at 11-13 weeks. When combining the cutoff levels of the three methods, mean PI of the uterine arteries ≥1.69, PAPP-A assay <0.96 multiple of median (MoM) and PlGF assay <0.91 MoM, the sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy were 56.7, 99.3, 89.5, 95.4 and 67%, respectively.

Conclusion

The combined measurement of maternal serum PAPP-A and PlGF concentrations and mean PI of the uterine arteries at 11-13 weeks of pregnancy may help to predict preeclampsia in primigravida when other parameters of preeclampsia prediction are normal. However, we need more studies on larger and variable populations to evaluate the use of those combined methods in preeclampsia prediction.

Renal Interlobar Vein Impedance Index as a First-Trimester Marker Does Not Predict Hypertensive Disorders of Pregnancy

OBJECTIVES

The purpose of this study was to examine whether the maternal renal interlobar vein impedance index as assessed by first-trimester sonography is able to predict the later development of hypertensive disorders of pregnancy.

METHODS

Venous Doppler parameters of both maternal kidneys were studied in 214 pregnant women at gestational ages of 11 weeks to 13 weeks 6 days. Patients were classified according to outcomes related to hypertensive disorders. Detection rates and areas under receiver operating characteristic curves were determined for the maternal renal interlobar vein impedance index as a first-trimester predictor of preeclampsia and gestational hypertension.

RESULTS

Among the 214 patients, 22 (10.3%) developed preeclampsia; 10 (4.7%) developed gestational hypertension; and 182 were unaffected by hypertensive disorders (controls; 85.0%). In the overall study population, there was no difference in the impedance index between the right (0.44; 95% confidence interval, 0.35-0.50) and left (0.43; 95% confidence interval, 0.35-0.53) sides (P = .86). The average impedance index did not differ among women destined to develop preeclampsia (0.46; 95% confidence interval, 0.38-0.57), gestational hypertension (0.39; 95% confidence interval, 0.33-0.46), or pregnancies uncomplicated by hypertensive disease (0.42; 95% confidence interval, 0.37-0.50; P = .15). Low detection rates and the area under the curve analysis demonstrated that the impedance index was not predictive of hypertensive disorders of pregnancy.

CONCLUSIONS

The maternal renal interlobar vein impedance index should not be considered a first-trimester marker of hypertensive disorders of pregnancy.

Association between Placental Lesions, Cytokines and Angiogenic Factors in Pregnant Women with Preeclampsia

Preeclampsia (PE) is considered the leading cause of maternal and perinatal morbidity and mortality. The placenta seems to play an essential role in this disease, probably due to factors involved in its formation and development. The present study aimed to investigate the association between placental lesions, cytokines and angiogenic factors in pregnant women with preeclampsia (PE). We evaluated 20 normotensive pregnant women, 40 with early-onset PE and 80 with late-onset PE. Placental samples were analyzed for histopathology, immunohistochemistry and determination of granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-10 (IL-10), transforming growth factor-beta 1 (TGF-β₁), tumor necrosis factor-alpha (TNF-α), placental growth factor (PlGF), vascular endothelial growth factor (VEGF), fms-like tyrosine-kinase-1 (Flt-1) and endoglin (Eng) levels. Higher percentages of increased syncytial knots and increased perivillous fibrin deposits, and greater levels of TNF-α, TGF-β1and Flt-1 were detected in placentas from early-onset PE. Levels of IL-10, VEGF and PlGF were decreased in PE versus normotensive placentas. Both the TNF-α/IL-10 and sFlt-1/PlGF ratios were higher in placental homogenate of early-onset PE than late-onset PE and control groups. The more severe lesions and the imbalance between TNF-α/IL-10 and PlGF/sFlt-1 in placentas from early-onset PE allows differentiation of early and late-onset PE and suggests higher placental impairment in early-onset PE.

First trimester screening for pre-eclampsia

The commercial availability of tests in the first trimester of pregnancy that predict the later development of pre-eclampsia has prompted considerable debate regarding their clinical utility and the degree to which they fulfil the longstanding principles of screening. Such tests have been shown to achieve detection rates for early pre-eclampsia (requiring delivery prior to 34 weeks) of over 90%, for a false positive rate of 10%. However, their capacity to predict later onset pre-eclampsia, which accounts for the bulk of the disease burden, is much more limited. The relatively few studies validating the performance of these tests in different populations have demonstrated significant variations in performance. Moreover, prospective research confirming that the administration of aspirin to those screened to be high risk reduces the incidence of pre-eclampsia is yet to be completed, and there may be harms in restricting aspirin therapy to this group, given its broader beneficial effect. In light of these limitations, further development of these tests is recommended prior to their introduction to clinical practice.

Doppler Assessment of Uterine Blood Flow in Pre-eclampsia: A Review

Doppler ultrasonography plays an ever-increasing role in obstetric imaging. Although commonly purported to assess blood flow, most studies in this area report purely on velocimetric parameters, rather than true volumetric flow. This review article highlights the physiological importance of this distinction, and reports on a literature review of uterine artery Doppler interrogation in the context of pre-eclampsia, which identified only four original research papers that attempted to assess blood flow. Attention is needed for true volumetric flow assessment in pre-eclampsia research, which may permit a more complete conceptualisation of the pathogenesis and haemodynamic consequences of this condition.