Activity of smooth muscles in human cervix and uterus

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.