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Traditional methods used for prediction of preterm delivery are subjective and inaccurate. The Electrohysterogram (EHG) and in particular the estimation of the EHG conduction velocity, is a relatively new promising method for detecting imminent preterm delivery. To date the analysis of the conduction velocity has relied on visual inspection of the signals. As a next step towards the introduction of EHG analysis as a clinical tool, we propose an automated method for EHG conduction velocity estimation for both the speed and direction of single spike propagation. The study design will be an observational cohort study. 100 pregnant women, gestational age between 23 + 5 and 34 weeks, admitted for threatening preterm labor or preterm prelabor rupture of membranes, will be included. The length of the cervical canal will be measured by transvaginal ultrasound. The EHG will be recorded using 4 electrodes in a fixed configuration. Contractions will be detected by analysis of the EHG and using an estimation of the intra uterine pressure. In the selected contractions, the delays between channels will be estimated by cross-correlation, and subsequently, the average EHG conduction velocity will be derived. Patients will be classified as labor group and non-labor group based on the time between measurement and delivery. The average conduction velocity and cervical length will be compared between the groups. The main study endpoints will be sensitivity, specificity, and area under the ROC curve for delivery within 1,2,4,7, and 14 days from the measurement. In this study, the diagnostic accuracy of EHG conduction velocity analysis will be evaluated for detecting preterm labor. Visual and automatic detection of contractions will be compared. Planar wave propagation will be assumed for the calculation of the CV vector. Current Controlled Trials ISRCTN07603227 .

Objective To evaluate the feasibility of non-invasive assessment of maternal cardiac and arterial characteristics throughout uncomplicated pregnancy and postpartum. Design A longitudinal evaluation throughout gestation, at seven weeks postpartum and at one year postpartum. Setting Antenatal outpatient clinic of Ziekenhuis Oost-Limburg (Genk, Belgium). Sample 16 women with uncomplicated pregnancy. Methods Impedance cardiography measurements were performed in supine, standing, and sitting position using a standard protocol with known reproducibility. SAS procedure MIXED for linear mixed models was used, and fitted to the data for each parameter separately: Data were binned in four-weekly intervals. Differences between gestational and postpartum measurements were evaluated by One-Sample Wilcoxon Signed Rank Tests. Data are presented as mean (standard error of mean). Main outcome measures Gestational and postnatal evolution of blood pressure, stroke volume, cardiac output, cardiac cycle time intervals, aortic flow characteristics, total peripheral vascular resistance, and thoracic fluid content. Results In all positions, stroke volume and cardiac output changed significantly throughout gestation (n=16; p≤0.0001), and supine values differed from standing (p≤0.008) and sitting positions (p≤0.048). As compared to early postpartum, all cardiovascular parameters remained unchanged after one year postpartum (n=12; p≥0.074), except for standing diastolic blood pressure which decreased with 5±2 mmHg (p=0.037). Conclusions Gestational evolutions of left ventricular output were similar to reported changes in literature, and were influenced by maternal position. Our study illustrates that impedance cardiography has the potential to become a useful tool in perinatal medicine to assess maternal hemodynamics The authors report that this study has not received any financial funding