Does knowledge of fetal outcome influence the interpretation of intrapartum cardiotocography and subsequent clinical management? A multicentre European study.

OBJECTIVE: To investigate whether knowledge of fetal outcome influences retrospective interpretation of cardiotocographic tracings and subsequent management recommendations. DESIGN: Prospective online study. SETTING: Seven university hospitals in five European countries. POPULATION: Forty-two intrapartum tracings from women with singleton pregnancies and uneventful antepartum courses. METHODS: Using an online questionnaire, 123 healthcare professionals interpreted 42 tracings without any knowledge of fetal outcome and provided management recommendations according to the National Institute of Clinical Excellence guidelines (intrapartum care). Two months later, 93 of the 123 participants re-interpreted the same re-ordered tracings, this time with information on the newborn's umbilical artery pH. OUTCOME MEASURES: Comparison of the evaluation of tracing features, overall tracing classification, and management recommendations between the initial analysis and re-interpretation. RESULTS: In newborns with umbilical artery pH ≤ 7.05, knowledge of the pH value led to significant changes in the evaluation of all basic tracing features. In this group, classification of tracings as 'normal' decreased 76% (8.8-2.1%, P < 0.001), whereas classification as 'pathologic' increased 51% (44.7-67.5%, P < 0.001). In newborns with pH 7.06-7.19, classification of tracings as 'normal' decreased 36% (22.4-14.4%, P < 0.001), and in those with pH ≥ 7.20, classification of tracings as 'pathologic' decreased 40% (23.4-14.1%, P < 0.001). In the group of newborns with umbilical artery pH ≤ 7.05, the recommendations 'no attention needed' decreased 75% (10.2-2.6%, P < 0.001), and the number of recommendations 'rapid reversal of hypoxic cause or immediate delivery' increased 70.3% (42.1-71.7%, P < 0.001). CONCLUSIONS: When provided with information on adverse fetal outcome, healthcare professionals provide a more pessimistic evaluation of basic tracing features, overall classification, and clinical management recommendations. TWEETABLE ABSTRACT: Knowledge of adverse fetal outcome leads to more pessimistic CTG evaluation and management recommendations.

A comparison of various linear and non-linear signal processing techniques to separate uterine EMG records of term and pre-term delivery groups.

Various linear and non-linear signal-processing techniques were applied to three-channel uterine EMG records to separate term and pre-term deliveries. The linear techniques were root mean square value, peak and median frequency of the signal power spectrum and autocorrelation zero crossing; while the selected non-linear techniques were estimation of the maximal Lyapunov exponent, correlation dimension and calculating sample entropy. In total, 300 records were grouped into four groups according to the time of recording (before or after the 26th week of gestation) and according to the total length of gestation (term delivery records--pregnancy duration >or=37 weeks and pre-term delivery records--pregnancy duration <37 weeks). The following preprocessing band-pass Butterworth filters were tested: 0.08-4, 0.3-4, and 0.3-3 Hz. With the 0.3-3 Hz filter, the median frequency indicated a statistical difference between those term and pre-term delivery records recorded before the 26th week (p = 0.03), and between all term and all pre-term delivery records (p = 0.012). With the same filter, the sample entropy indicated statistical differences between those term and pre-term delivery records recorded before the 26th week (p = 0.035), and between all term and all pre-term delivery records (p = 0.011). Both techniques also showed noticeable differences between term delivery records recorded before and after the 26th week (p

Electromyographic activity of the uterus above the placental implantation site.

The aim of this study was to evaluate the electromyographic (EMG) activity of the uterus concerning the placental implantation site. In a clinical trial, 55 pregnant women in the last trimester of pregnancy were enrolled. They were divided into two major groups: 25 women had placental implantation site on the anterior and 30 women on the posterior uterine wall. With regard to the presence/nonpresence of contractions, each group was further divided into two subgroups. Uterine EMG activity was recorded by electrodes placed on the abdominal wall. All signals were transferred through a series of amplifiers. Amplified and filtered EMG signals were digitized and written on a hard disk, simultaneously with the signals of external tocodynamometry. From the 30-min EMG recording, we calculated the average root mean square (RMS) and the average median frequency (MF) of the signal. A significant difference of the abdominal EMG activity concerning the placental implantation site was found only in pregnant women with contractions. The RMS was significantly lower in the placental implantation site on the anterior uterine wall, whereas the MF was significantly higher. It can be concluded that the placental implantation site influences the uterine EMG activity registered through the abdominal wall, especially when registered above the placental implantation site.