Author/Editor		Rudel, Drago; Pajntar, Marjan
Title		Active contractions of the cervix in the latent phase of labour
Type		članek
Source		Br J Obstet Gynaecol
Vol. and No.		Letnik 106
Publication year		1999
Volume		str. 446-52
Language		eng
Abstract		Objective. To study the activity of the human uterine cervix at the onset of labour and further characterise cervical asynchronous electromyograhic (EMG) activity in the latent phase. Design. prospective observational study. Setting. Clinical hospital in Ljubljana. Participants. Forty-seven healthy nulliparous women with relatively unripe cervices requiring induction of labour. Methods. Simultanous registration of a servical 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. Main outcome measures. 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. Results 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 burts had low avarage median frequeny (0.3 Hz). In seven women bursts were superimposed onto a background EMG (median frequency = 1.2 Hz). Conclusions: Burts 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 stretchning during a contraction. The EMG frequency content suggests two different contraction mechanisms or a different origin of the EMG in the cervix.
Descriptors		CERVIX UTERI ELECTROMYOGRAPHY UTERINE CONTRACTION LABOR, INDUCED AMNION OXYTOCIN MANOMETRY PROSPECTIVE STUDIES UTERUS PREGNANCY