Search

Objective To identify the effect of cervical muscle activity as an additional factor influencing the duration of the latent and active phase of labour. Design Prospective observational study. Setting The Ljubljana Maternity Hospital. Participants Fifty healthy nulliparous women requiring induction of labour having relatively unripe cervices. Methods At the onset of labour an open-ended catheter was inserted to measure intrauterine pressure during the latent and active phase of labour. Electromyographic activity of the cervix was registered by two bipolar spiral needle electrodes placed in the transverse direction on the proximal part of the cervix in the vagina. The mean intensity of distinctive peaks in an electromyographic spectrogram were calculated in the time/frequency domain. Multiple linear regression was used to find factors affecting the duration of the latent and active phase of labour. Main outcome measures Duration of the latent and active phase of labour. Results Eleven independent variables explained 64% of the variance of the latent phase duration, the most important being the effacement and consistency of the cervix, and intensity of electromyographic signals. For the duration of the active phase the same variables explained 36% of the variance; the most important variables were mean duration of uterine contractions, mean maximum intensity of uterine contractions and the newborn's head circumference. Conclusions The cervical smooth muscle activity, expressed as an electromyographic signal, contributes to the duration of the latent phase but not to the duration of the active phase. However, frequent cervical contractions are not associated with a longer latent phase.

Objective: To estimate the risk of preterm birth in women admitted to the tertiary maternity hospital for preterm contractions by measuring electrical uterine activity. Study design: The study included 47 patients with contractions between the 25th and 35th week of gestation and additional risk factors for preterm delivery. Uterine electrical activity was recorded using bipolar electrodes placed on the abdominal surface. A logistic model with the electromyographic and obstetric data was built, preterm delivery before 37th week of gestation being the outcome measure. Results: Seventeen patients (36%) delivered before term. Logistic regression model suggested only the intensity of electrical uterine activity and woman’s body weight to be significant predictors of preterm delivery, with high values related to preterm birth. They predict preterm delivery with the sensitivity of 47% and specificity of 90%. Conclusion: We propose uterine EMG as a simple, non-invasive means to estimate the risk of preterm birth in a high-risk population with multiple risk factors present.

Objective: To find the similarities and dissimilarities between the activity of the human smooth muscles in the cervix and in the uterine corpus at the onset of induced labour. Study design: Electromyographic activity was measured in 14 primiparous women after amniotomy. The data were sampled and stored digitally in real time. For statistical analysis, the first 20 min of recordings following amniotomy were analyzed. The ratio between the mean activity at a given time and the mean activity over the whole 20 min was used for the comparison between the cervical and uterine activity. Results: The analysis of correlation showed that the electromyographic activity in the cervix differed from that in the uterine corpus in the majority of the enrolled cases. Conclusions: The muscular activity in the cervix is independent of that in the uterine corpus at the onset of induced labour.

Background:The purpose of this study was the possibility to follow the progress of labour using electromyographic (EMG) signals obtained from the uterine corpus and the cervix. Methods: 28 healty primiparous women with induced labour at an age from 19 to 29 years were enrolled in the study. For interpretation of EMG signals Sample entropy (SampEn), the measure of time series regularity was used. SampEn values were related to the progress of labour recorded in the partogram. h e main outcome is association between labour progress and values of SampEn. Results: Approaching the childbirth during normally progressing labour, regular activity of uterine corpus muscles and cervical muscles is indicated as a decreasing trend in values of SampEn. A delay in the active phase of labour due to active contractions of cervical circular muscles is indicated in greater values of SampEn calculated from cervical EMG activity. Conclusions: By measuring and processing of EMG signals from the uterine corpus and the cervix an obstetrician can obtain an additional useful information on the progress of labour.

To study the activity of the human uterine cervix at the onset of labour and further characterise cervical asynchronous electromyographic (EMG) activity in the latent phase.Prospective observational study.Clinical hospital in Ljubljana.Forty-seven healthy nulliparous women with relatively unripe cervices requiring induction of labour.Simultaneous registration of a cervical EMG and of the intrauterine pressure at the very early stage of labour; subsequent EMG signal processing to determine its time, amplitude and frequency parameters.Simultaneous comparison of the cervical EMG and the mechanical activity of the uterine corpus to deduce electrical properties of the cervical smooth muscle tissue and its activity.EMG bursts, asynchronous with the contractions of the uterine corpus, were registered in 20 out of 47 women. In 14 women bursts appeared independent of uterine corpus contractions and in six they followed the peak of contractions. The bursts had low average median frequency (0.3 Hz). In seven women bursts were superimposed onto a background EMG (median frequency = 1.2 Hz).Bursts in the cervical EMG may appear asynchronously with the uterine contractions. Bursts not related to contractions suggest active and independent cervical muscle activity. The bursts which follow contractions may be an active response of the cervical musculature to passive stretching during a contraction. The EMG frequency content suggests two different contraction mechanisms or a different origin of the EMG in the cervix.

The electrical activity of the cervix can be measured during labour. The influence of oxytocin on electromyographic (EMG) activity of the cervical musculature was studied in 80 primiparous women after induction of labor. The highest electrical activity registered at the time of uterine contraction and between two contractions was used for analysis. The basic pattern of oxytocin-produced changes in muscular contractions in the cervix observed via EMG activity is that of the activity increasing with contractions of the uterine corpus and diminishing between contractions. The effect of oxytocin on cervical musculature is different in ripe and unripe cervices.

In order to accelerate rehabilitation of patients with peripheral nerve lesions, hypnosis was employed to encourage them voluntarily to move those muscles with weak re-innervation and to achieve the best possible activity of the affected muscle' groups. By measuring muscle force and endurance and by observing the electrical activity of the affected muscles, it was found that the activity of the affected muscles was much better while patients were in hypnosis than when they were in the waking state. The patients were able to contract even paretic muscles having only weak re-innervation with such strength, that clinically perceptible contraction of the muscles and movement of paretic extremities occurred. Such early and improved activation is very important for prevention of much permanent damage.