Repeat placental growth factor-based testing in women with suspected preterm pre-eclampsia (PARROT-2): a multicentre, parallel-group, superiority, randomised controlled trial.

BACKGROUND: Placental growth factor (PlGF)-based testing has high diagnostic accuracy for predicting pre-eclampsia needing delivery, significantly reducing time to diagnosis and severe maternal adverse outcomes. The clinical benefit of repeat PlGF-based testing is unclear. We aimed to determine whether repeat PlGF-based testing (using a clinical management algorithm and nationally recommended thresholds) reduces adverse perinatal outcomes in pregnant individuals with suspected preterm pre-eclampsia. METHODS: In this multicentre, parallel-group, superiority, randomised controlled trial, done in 22 maternity units across England, Scotland, and Wales, we recruited women aged 18 years or older with suspected pre-eclampsia between 22 weeks and 0 days of gestation and 35 weeks and 6 days of gestation. Women were randomly assigned (1:1) to revealed repeat PlGF-based testing or concealed repeat testing with usual care. The intervention was not masked to women or partners, or clinicians or data collectors, due to the nature of the trial. The trial statistician was masked to intervention allocation. The primary outcome was a perinatal composite of stillbirth, early neonatal death, or neonatal unit admission. The primary analysis was by the intention-to-treat principle, with a per-protocol analysis restricted to women managed according to their allocation group. The trial was prospectively registered with the ISRCTN registry, ISRCTN 85912420. FINDINGS: Between Dec 17, 2019, and Sept 30, 2022, 1253 pregnant women were recruited and randomly assigned treatment; one patient was excluded due to randomisation error. 625 women were allocated to revealed repeat PlGF-based testing and 627 women were allocated to usual care with concealed repeat PlGF-based testing (mean age 32·3 [SD 5·7] years; 879 [70%] white). One woman in the concealed repeat PlGF-based testing group was lost to follow-up. There was no significant difference in the primary perinatal composite outcome between the revealed repeat PlGF-based testing group (195 [31·2%]) of 625 women) compared with the concealed repeat PlGF-based testing group (174 [27·8%] of 626 women; relative risk 1·21 [95% CI 0·95-1·33]; p=0·18). The results from the per-protocol analysis were similar. There were four serious adverse events in the revealed repeat PlGF-based testing group and six in the concealed repeat PlGF-based testing group; all serious adverse events were deemed unrelated to the intervention by the site principal investigators and chief investigator. INTERPRETATION: Repeat PlGF-based testing in pregnant women with suspected pre-eclampsia was not associated with improved perinatal outcomes. In a high-income setting with a low prevalence of adverse outcomes, universal, routine repeat PlGF-based testing of all individuals with suspected pre-eclampsia is not recommended. FUNDING: Tommy's Charity, Jon Moulton Charitable Trust, and National Institute for Health and Care Research Guy's and St Thomas' Biomedical Research Centre.

Placental growth factor testing to assess women with suspected pre-eclampsia: a multicentre, pragmatic, stepped-wedge cluster-randomised controlled trial.

BACKGROUND: Previous prospective cohort studies have shown that angiogenic factors have a high diagnostic accuracy in women with suspected pre-eclampsia, but we remain uncertain of the effectiveness of these tests in a real-world setting. We therefore aimed to determine whether knowledge of the circulating concentration of placental growth factor (PlGF), an angiogenic factor, integrated with a clinical management algorithm, decreased the time for clinicians to make a diagnosis in women with suspected pre-eclampsia, and whether this approach reduced subsequent maternal or perinatal adverse outcomes. METHODS: We did a multicentre, pragmatic, stepped-wedge cluster-randomised controlled trial in 11 maternity units in the UK, which were each responsible for 3000-9000 deliveries per year. Women aged 18 years and older who presented with suspected pre-eclampsia between 20 weeks and 0 days of gestation and 36 weeks and 6 days of gestation, with a live, singleton fetus were invited to participate by the clinical research team. Suspected pre-eclampsia was defined as new-onset or worsening of existing hypertension, dipstick proteinuria, epigastric or right upper-quadrant pain, headache with visual disturbances, fetal growth restriction, or abnormal maternal blood tests that were suggestive of disease (such as thrombocytopenia or hepatic or renal dysfunction). Women were approached individually, they consented for study inclusion, and they were asked to give blood samples. We randomly allocated the maternity units, representing the clusters, to blocks. Blocks represented an intervention initiation time, which occurred at equally spaced 6-week intervals throughout the trial. At the start of the trial, all units had usual care (in which PlGF measurements were also taken but were concealed from clinicians and women). At the initiation time of each successive block, a site began to use the intervention (in which the circulating PlGF measurement was revealed and a clinical management algorithm was used). Enrolment of women continued for the duration of the blocks either to concealed PlGF testing, or after implementation, to revealed PlGF testing. The primary outcome was the time from presentation with suspected pre-eclampsia to documented pre-eclampsia in women enrolled in the trial who received a diagnosis of pre-eclampsia by their treating clinicians. This trial is registered with ISRCTN, number 16842031. FINDINGS: Between June 13, 2016, and Oct 27, 2017, we enrolled and assessed 1035 women with suspected pre-eclampsia. 12 (1%) women were found to be ineligible. Of the 1023 eligible women, 576 (56%) women were assigned to the intervention (revealed testing) group, and 447 (44%) women were assigned to receive usual care with additional concealed testing (concealed testing group). Three (1%) women in the revealed testing group were lost to follow-up, so 573 (99%) women in this group were included in the analyses. One (<1%) woman in the concealed testing group withdrew consent to follow-up data collection, so 446 (>99%) women in this group were included in the analyses. The median time to pre-eclampsia diagnosis was 4·1 days with concealed testing versus 1·9 days with revealed testing (time ratio 0·36, 95% CI 0·15-0·87; p=0·027). Maternal severe adverse outcomes were reported in 24 (5%) of 447 women in the concealed testing group versus 22 (4%) of 573 women in the revealed testing group (adjusted odds ratio 0·32, 95% CI 0·11-0·96; p=0·043), but there was no evidence of a difference in perinatal adverse outcomes (15% vs 14%, 1·45, 0·73-2·90) or gestation at delivery (36·6 weeks vs 36·8 weeks; mean difference -0·52, 95% CI -0·63 to 0·73). INTERPRETATION: We found that the availability of PlGF test results substantially reduced the time to clinical confirmation of pre-eclampsia. Where PlGF was implemented, we found a lower incidence of maternal adverse outcomes, consistent with adoption of targeted, enhanced surveillance, as recommended in the clinical management algorithm for clinicians. Adoption of PlGF testing in women with suspected pre-eclampsia is supported by the results of this study. FUNDING: National Institute for Health Research.

Efficacy of transvaginal cervical cerclage in women at risk of preterm birth following previous emergency cesarean section.

INTRODUCTION: Emergency cesarean sections (EMCS) are associated with subsequent preterm birth, particularly at full dilation (FDCS), which is a cause of both second trimester miscarriages and early, recurrent spontaneous preterm birth (sPTB). The optimal management for these women in subsequent pregnancies is currently unknown. This study aims to assess efficacy of transvaginal cervical cerclage (TVC) in prevention of preterm birth among women who have had an EMCS followed by a subsequent late miscarriage or sPTB. MATERIAL AND METHODS: A historical cohort study was performed assessing outcomes of women attending the Preterm Surveillance Clinic at St Thomas' Hospital, London, who received TVC, with a history of EMCS (pregnancy A) followed by a sPTB/late miscarriage (pregnancy B) and a subsequent pregnancy (pregnancy C). A historical reference group managed in the same clinic was identified comprising women with any risk factor for sPTB, who required TVC. Incidence of delivery >24 to <30 weeks' gestation was compared with relative risk and 95% confidence intervals (CI). Subgroup analysis was carried out assessing women who had a previous FDCS. RESULTS: 209 women with a previous EMCS during labor (50 with FDCS), followed by sPTB/late miscarriage were identified. 178 progressed beyond 24 weeks; of these, 56 received TVC and formed the study group. 905 high-risk women were identified; of these, 154 received TVC and formed the reference group. Despite TVC treatment, 17/56 (30%) of the study group delivered <30 weeks' gestation compared with 5/154 (3%) of the reference group (RR 9.4, 95% CI 3.6-24.2, P < .001). In the subset of 17 women in the study group with a previous FDCS, followed by sPTB/late miscarriage, 6/17 (35%) delivered <30 weeks' gestation, significantly higher than the reference group (P < .001) but similar to EMCS at less than full dilation (35% vs 28%, P = .596). Overall, 33/72 (46%) women receiving cerclage with prior EMCS had either a mid-trimester loss or delivery <30 weeks. CONCLUSIONS: Transvaginal cervical cerclage appears less effective in preventing preterm birth among pregnant women who have had an EMCS followed by a sPTB/late miscarriage compared with other high-risk women. The lack of efficacy in the subgroup with an FDCS was similar.

Diagnostic accuracy of repeat placental growth factor measurements in women with suspected preeclampsia: A case series study.

INTRODUCTION: Preeclampsia affects about 3% of singleton pregnancies and is characterized by placental dysfunction. It is associated with significant maternal and perinatal morbidity and mortality. The diagnosis of preeclampsia remains a challenge, and the clinical course can develop for weeks before a diagnosis is confirmed. National guidelines have approved placental growth factor (PlGF) testing to rule out suspected preeclampsia, but the utility of repeated PlGF measurement is unknown. The aim of this case series analysis was to evaluate the test performance of repeated PlGF sampling in women presenting with suspected preeclampsia, and to describe relevant clinical outcomes. MATERIAL AND METHODS: Women who presented to maternity services with suspected preeclampsia between 20+0 and 36+6  weeks' gestation who underwent repeat PlGF sampling with a minimum test interval of 7 days were assessed. The outcomes were delivery for preeclampsia within 14 days of sampling, the proportion changing PlGF categories, and time to delivery. RESULTS: In total, 289 women with suspected preeclampsia undergoing repeat PlGF sampling were included. PlGF <100 pg/mL had a high sensitivity (87.5%, 95% confidence interval [CI] 67.6%-97.3%) and a negative predictive value (97.7%, 95% CI 93.5%-99.5%) at the initial test (receiver operating characteristic [ROC] area 0.79, 95% CI 0.68-0.89). Similar test performance was seen for PlGF <100 pg/mL when undertaken as a repeat test (sensitivity 90.7%, 95% CI 85.2%-95.9%, negative predictive value 92.2%, 95% CI 85.3-96.6%). Overall, 25.6% of women changed PlGF category between the first and second PlGF tests. For each PlGF category, determination of time to delivery was similar for first and second tests. CONCLUSIONS: Repeat PlGF measurement demonstrates high negative predictive value for determining preeclampsia requiring delivery in 14 days. Repeat testing may be clinically useful to risk stratify women with ongoing symptoms of disease. Confirmation of the impact of these findings is required in further studies.

Repeat Placental Growth Factor-Based Testing in Women With Suspected Preterm Preeclampsia: A Stratified Analysis of the PARROT-2 Trial.

BACKGROUND: PlGF (placental growth factor)-based testing reduces severe maternal adverse outcomes. Repeat PlGF-based testing is not associated with improved perinatal or maternal outcomes. This planned secondary analysis aimed to determine whether there is a subgroup of women who benefit from repeat testing. METHODS: Pregnant individuals with suspected preterm preeclampsia were randomized to repeat revealed PlGF-based testing, compared with usual care where testing was concealed. Perinatal and maternal outcomes were stratified by trial group, by initial PlGF-based test result, and by PlGF-based test type (PlGF or sFlt-1 [soluble fms-like tyrosine kinase-1]/PlGF ratio). RESULTS: A total of 1252 pregnant individuals were included. Abnormal initial PlGF-based test identified a more severe phenotype of preeclampsia, at increased risk of adverse maternal and perinatal outcomes. Repeat testing was not significantly associated with clinical benefit in women with abnormal initial results. Of women with a normal initial result, 20% developed preeclampsia, with the majority at least 3 to 4 weeks after initial presentation. Repeat test results were more likely to change from normal to abnormal in symptomatic women (112/415; 27%) compared with asymptomatic women (163/890; 18%). A higher proportion of symptomatic women who changed from normal to abnormal were diagnosed with preeclampsia, compared with asymptomatic women. CONCLUSIONS: Our results do not demonstrate evidence of the clinical benefit of repeating PlGF-based testing if the initial result is abnormal. Judicious use of repeat PlGF-based testing to stratify risk may be considered at least 2 weeks after a normal initial test result, particularly in women who have symptoms or signs of preeclampsia. REGISTRATION: URL: https://www.isrctn.com/ISRCTN85912420; Unique identifier: ISRCTN85912420.

Antiplatelet agents for the prevention of pre-eclampsia.

Pre-eclampsia (P-EC) remains a significant problem in modern obstetrics occurring in 2 to 4% of women. The disease is still responsible for 60,000 maternal deaths worldwide annually. An increased understanding of the underlying pathophysiology has resulted in a more scientific approach to prophylaxis and prevention, yet the underlying disease mechanisms are not fully understood. The role of combining good prediction with prevention has yet to be established but has the potential to target health resources far more efficiently. Good prediction may also impact on tailoring antenatal care appropriately, with prophylactic measures for high-risk women becoming the highly preferred management option. Antiplatelet agents reduce the incidence and complications of P-EC and should be considered prophylactically in those at high risk of the disease.

Prognostic indicators of severe disease in late preterm pre-eclampsia to guide decision making on timing of delivery: The PEACOCK study.

OBJECTIVE: To assess the diagnostic performance of angiogenic biomarkers in determining need for delivery in seven days in women with late preterm preeclampsia. STUDY DESIGN: In a prospective observational cohort study in 36 maternity units across England and Wales, we studied the diagnostic accuracy of placental growth factor (PlGF) and sFlt-1 in determining the risk of complications requiring delivery in late preterm (34+0 to 36+6 weeks' gestation) preeclampsia. Angiogenic biomarkers were measured using the Quidel (PlGF) and Roche (sFlt-1:PlGF ratio) assays. Additional clinical data was obtained for use within the established 'Prediction of complications in early-onset pre-eclampsia' (PREP)-S prognostic model. Biomarkers were assessed using standard methods (sensitivity, specificity, Receiver Operator Curve areas). Estimated probability of early delivery from PREP-S was compared to actual event rates. MAIN OUTCOME MEASURES: Clinically indicated need for delivery for pre-eclampsia within seven days. RESULTS: PlGF (Quidel) testing had high sensitivity (97.9%) for delivery within seven days, but negative predictive value was only 71.4%, with low specificity (8.4%), with similar results from sFlt-1/PlGF assay. The area under the curve for PlGF was 0.60 (SE 0.03), and 0.65 (0.03), and 0.64 (0.03) for PREP-S in combination with PlGF, and sFlt-1:PlGF, respectively. CONCLUSIONS: Angiogenic biomarkers do not add to clinical assessment to help determine need for delivery for women with late preterm pre-eclampsia. Existing models developed in women with early-onset pre-eclampsia to predict complications cannot be used to predict clinically indicated need for delivery in women with late preterm pre-eclampsia.

Placental growth factor measurements in the assessment of women with suspected Preeclampsia: A stratified analysis of the PARROT trial.

OBJECTIVE: Placental growth factor testing decreases time to recognition of preeclampsia and may reduce severe maternal adverse outcomes. This analysis aims to describe the clinical phenotype of women by PlGF concentration, and to determine the mechanism(s) underpinning the reduction in severe maternal adverse outcomes in the PARROT trial, in order to inform how PlGF testing may be optimally used within clinical management algorithms. STUDY DESIGN: This was a planned secondary analysis from the PARROT trial that compared revealed PlGF testing and management guidance with usual care in the assessment of women with suspected preterm preeclampsia. MAIN OUTCOME MEASURES: Maternal and perinatal outcomes following stratification of women by trial group, and measured PlGF concentration. RESULTS: 1006 women were included. PlGF < 100 pg/ml identified women with more marked hypertension, increased adverse maternal outcomes and preterm delivery rates, and higher rates of small for gestational age infants. There was a reduction in adverse maternal outcomes in women whose results were revealed when PlGF levels were 12-100 pg/ml compared to usual care (3.8% vs 6.9%; aOR 0.15(95% CI 0.03-0.92). There was no significant difference in gestation at delivery between concealed or revealed groups in any PlGF categories. CONCLUSION: Low PlGF concentrations are associated with severe preeclampsia. The reduction in severe adverse maternal outcomes may be mediated through quicker diagnosis and intensive surveillance, as recommended by the management algorithm for those at increased risk. PlGF is particularly beneficial in those who test 12-100 pg/ml, as these may be women with silent multi-organ disease who otherwise may go undetected.

Recent advances in the diagnosis and management of pre-eclampsia.

Pre-eclampsia complicates around 5% of pregnancies and hypertensive disorders of pregnancy are responsible for over 60,000 maternal deaths worldwide annually. Pre-eclampsia is characterized by hypertension and features of multiple organ disease. Diagnosis remains a challenge as clinical presentation is highly variable and even with severe disease a woman can be asymptomatic. Pre-eclampsia is characterized by abnormal placentation with subsequent maternal inflammatory and vascular response. Improved understanding of the underlying pathophysiology relating to the role of angiogenic factors, has emerged and placed intense interest on their role in prognostic modelling or diagnosis of pre-eclampsia. This article summarizes new developments in diagnosis with a focus on angiogenic biomarkers for prediction of disease onset, and recent advances in management strategies for patients with pre-eclampsia.

How placental growth factor detection might improve diagnosis and management of pre-eclampsia.

Pre-eclampsia complicates around 5% of pregnancies and hypertensive disorders of pregnancy are responsible for over 60,000 maternal deaths worldwide annually. Identifying women with pre-eclampsia is a major goal of antenatal care in order to target increased surveillance, allow stabilizing therapies to be implemented and to enable timely delivery. Current risk assessment is based on clinical history, imperfect assessment of clinical signs (e.g., hypertension and proteinuria) and nonspecific biochemical markers, all of which are subject to considerable error. This is further confounded by underlying maternal disease such as chronic hypertension or renal pathology. Angiogenic factors reflect the underlying pathophysiology of pre-eclampsia and there is emerging evidence that they can now be used for more accurate risk assessment. The most promising of these factors include placental growth factor and soluble fms-like tyrosine kinase-1. Used at point of care, these can accurately discriminate true disease in suspected cases and subsequent need for delivery.

Can a low-resource-use blood pressure device impact on global maternal mortality?

BACKGROUND: Hypertension in pregnancy in the developing world is largely underreported, misdiagnosed, and untreated, especially in rural settings, though it contributes significantly to maternal and perinatal morbidity and mortality. To reduce general global cardiovascular and cerebrovascular morbidity and mortality, the World Health Organization aims to develop and validate low-resource-use blood pressure devices for use in developing nations. OBJECTIVE AND METHODS: To describe how existing antenatal care systems provide a useful and relevant model through which to evaluate the potential for this initiative to be applied in low-resource settings and to offer opportunities for much needed further research.

Validation of the Nissei DS-400 in a low-resource setting.

OBJECTIVE: Hypertension affects approximately one billion individuals worldwide. The effective management of hypertension requires accurate measurement and monitoring of blood pressure. We evaluated the accuracy of a low cost self-measurement oscillometric device, with features suitable for use in a low-resource setting, in an adult population in the developing world according to the International Protocol of the European Society of Hypertension. METHODS: Trained observers using a double-headed stethoscope took nine sequential same arm measurements from 33 participants, alternating between mercury sphygmomanometry and the test device. Anyone with an arrhythmia or unclear Korotkoff sounds was excluded. Data were analyzed according to the protocol guidelines. RESULTS: The device passed all the criteria of the International Protocol with 78/95/99 and 80/95/99 of systolic and diastolic differences, respectively, within 5/10/15 mmHg of the mercury standard. It also achieved the Association for the Advancement of Medical Instrumentation criteria with a mean difference (standard deviation) of 0.8 (4.4) mmHg and -0.9 (4.5) mmHg for systolic blood pressure and diastolic blood pressure, respectively. CONCLUSION: The Nissei DS-400 can be recommended for use in the adult population, particularly in the developing world. Its impressive performance may be related to theoretical factors within the patient population and environment (e.g. temperature, humidity and altitude) that could influence the device's performance.