A historical cohort study

OK Funding Information: Catarina R. Palma dos Reis acknowledges support from a Clarendon Fund Scholarship. Publisher Copyright: © 2023 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG).Introduction: The velocity of fetal deterioration in fetal growth restriction is extremely variable, which makes monitoring and counseling very challenging. The soluble fms-like tyrosine kinase to placental growth factor (sFlt1/PlGF) ratio provides a readout of the vasoactive environment that correlates with preeclampsia and fetal growth restriction and that could be useful to predict fetal deterioration. Previous studies showed a correlation between higher sFlt1/PlGF ratios and lower gestational ages at birth, although it is unclear whether this is due to the increased incidence of preeclampsia. Our goal was to evaluate whether the sFlt1/PlGF ratio predicts faster fetal deterioration in early fetal growth restriction. Material and methods: This was a historical cohort study in a tertiary maternity hospital. Data from singleton pregnancies with early fetal growth restriction (diagnosed before 32 gestational weeks) confirmed after birth monitored between January 2016 and December 2020 were retrieved from clinical files. Cases of chromosomal/fetal abnormalities, infection and medical terminations of pregnancy were excluded. The sFlt1/PlGF ratio was acquired at diagnosis of early fetal growth restriction in our unit. The correlation of log10 sFlt1/PlGF with latency to delivery/fetal demise was assessed with linear, logistic (positive sFlt1/PlGF if >85) and Cox regression excluding deliveries for maternal conditions and controlling for preeclampsia, gestational age at time of ratio test, maternal age and smoking during pregnancy. Receiver-operating characteristic (ROC) analysis tested the performance of sFlt1/PlGF ratio in predicting delivery for fetal reasons in the following week. Results: 125 patients were included. Mean sFlt1/PlGF ratio was 91.2 (SD 148.7) and 28% of patients had a positive ratio. A higher log10 sFlt1/PlGF ratio predicted shorter latency for delivery/fetal demise in linear regression after controlling for confounders, β = −3.001, (−3.713 to −2.288). Logistic regression with ratio positivity confirmed these findings (latency for delivery 5.7 ± 3.32 weeks for ratios ≤85 vs 1.9 ± 1.52 weeks for ratios >85); β = −0.698 (−1.064 to −0.332). Adjusted Cox regression showed that a positive ratio confers a significantly positive hazard ratio (HR) for earlier delivery/fetal demise, HR 9.869 (5.061–19.243). ROC analysis showed an area under the curve of 0.847 (SE ± 0.06). Conclusions: sFlt1/PlGF ratio is correlated with faster fetal deterioration in early fetal growth restriction, independently of preeclampsia.publishersversionepub_ahead_of_prin

A Preliminary Exploration of the Placental Position Influence on Uterine Electromyography Using Fractional Modelling

Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.The uterine electromyogram, also called electrohysterogram (EHG), is the electrical signal generated by uterine contractile activity. The EHG has been considered an expanding technique for pregnancy monitoring and preterm risk evaluation. Data were collected on the abdominal surface. It has been speculated the effect of the placenta location on the characteristics of the EHG. In this work, a preliminary exploration method is proposed using the average spectra of Alvarez waves contractions of subjects with anterior and non-anterior placental position as a basis for the triple-dispersion Cole model that provides a best fit for these two cases. This leads to the uterine impedance estimation for these two study cases. Non-linear least square fitting (NLSF) was applied for this modelling process, which produces electric circuit fractional models’ representations. A triple-dispersion Cole-impedance model was used to obtain the uterine impedance curve in a frequency band between 0.1 and 1 Hz. A proposal for the interpretation relating the model parameters and the placental influence on the myometrial contractile action is provided. This is the first report regarding in silico estimation of the uterine impedance for cases involving anterior or non-anterior placental positions.publishersversionpublishe

Adaptive Filtering for the Maternal Respiration Signal Attenuation in the Uterine Electromyogram

Funding Information: For Arnaldo Batista and Manuel Ortigueira, this work was supported by the Portuguese National Funds, through the FCT Foundation for Science and Technology, within the scope of the CTS Research Unit, Center of Technology and Systems, UNINOVA, under the project UIDB/00066/2020 (FCT). Helena Mouriño was financed by national funds through FCT, Fundação para a Ciência e a Tecnologia, under the project UIDB/00006/2020. Publisher Copyright: © 2022 by the authors.The electrohysterogram (EHG) is the uterine muscle electromyogram recorded at the abdominal surface of pregnant or non-pregnant woman. The maternal respiration electromyographic signal (MR-EMG) is one of the most relevant interferences present in an EHG. Alvarez (Alv) waves are components of the EHG that have been indicated as having the potential for preterm and term birth prediction. The MR-EMG component in the EHG represents an issue, regarding Alv wave application for pregnancy monitoring, for instance, in preterm birth prediction, a subject of great research interest. Therefore, the Alv waves denoising method should be designed to include the interference MR-EMG attenuation, without compromising the original waves. Adaptive filter properties make them suitable for this task. However, selecting the optimal adaptive filter and its parameters is an important task for the success of the filtering operation. In this work, an algorithm is presented for the automatic adaptive filter and parameter selection using synthetic data. The filter selection pool comprised sixteen candidates, from which, the Wiener, recursive least squares (RLS), householder recursive least squares (HRLS), and QR-decomposition recursive least squares (QRD-RLS) were the best performers. The optimized parameters were L = 2 (filter length) for all of them and λ = 1 (forgetting factor) for the last three. The developed optimization algorithm may be of interest to other applications. The optimized filters were applied to real data. The result was the attenuation of the MR-EMG in Alv waves power. For the Wiener filter, power reductions for quartile 1, median, and quartile 3 were found to be −16.74%, −20.32%, and −15.78%, respectively (p-value = 1.31 × 10−12).publishersversionpublishe

Automatic contraction detection using uterine electromyography

UIDB/00066/2020 UID/MAT/04561/2019 PD/BDE/150312/2019Electrohysterography (EHG) is a promising technique for pregnancy monitoring and preterm risk evaluation. It allows for uterine contraction monitoring as early as the 20th gestational week, and it is a non-invasive technique based on recording the electric signal of the uterine muscle activity from electrodes located in the abdominal surface. In this work, EHG-based contraction detection methodologies are applied using signal envelope features. Automatic contraction detection is an important step for the development of unsupervised pregnancy monitoring systems based on EHG. The exploratory methodologies include wavelet energy, Teager energy, root mean square (RMS), squared RMS, and Hilbert envelope. In this work, two main features were evaluated: contraction detection and its related delineation accuracy. The squared RMS produced the best contraction (97.15 ± 4.66%) and delineation (89.43 ± 8.10%) accuracy and the lowest false positive rate (0.63%). Despite the wavelet energy method having a contraction accuracy (92.28%) below the first-rated method, its standard deviation was the second best (6.66%). The average false positive rate ranged between 0.63% and 4.74%—a remarkably low value.publishersversionpublishe

Alvarez waves in pregnancy: a comprehensive review

Alvarez waves are local rhythmic contractions of the myometrium with high frequency and low intensity. They can be detected using internal or external tocography and electrohysterography. Some researchers correlate these small contractions with the initiation of labor, since they have been described as a pattern representing the uterine response to prostaglandin production. Other authors either do not validate a causality relation between Alvarez waves and labor or suggest that they have low predictive value for preterm labor. Alvarez waves’ research has become a multidisciplinary subject with inputs ranging from medical science, biomedical engineering, and related areas. A comprehensive review is herein conducted to summarize the state of the art regarding Alvarez waves and their role in the initiation of labor, namely in preterm birth. The results show that a large number of studies have analyzed and characterized Alvarez waves without necessarily digging into their relationship with labor. Publications were categorized in three groups: (A) reports about morphology and characterization of Alvarez waves; (B) publications reporting a positive causality relation between Alvarez waves and labor; and (C) publications reporting an absence of causality regarding the previous hypothesis. Studies in group B outnumbered those in group C. A critical analysis is presented.publishersversionpublishe

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)