Uterine activity during spontaneous labour after previous lower-segment caesarean section

Summary. Uterine activity was measured in three groups of labouring women who previously had a caesarean section (CS): group A included women with a previous elective CS before labour or in the early latent phase of labour and no previous vaginal delivery; group B included women with a CS in the active phase of labour and no previous vaginal delivery; group C included women with a CS and a vaginal delivery either before or after the abdominal delivery. The active contraction area profiles in the three groups were compared with those of matched control groups of nulliparae and multiparac without a uterine scar. Group A had a uterine activity profile similar to that in control nulliparae and significantly higher than that in control multiparae. The uterine activity in group B was less than that in matched nulliparae but was similar to that in matched multiparae. Group C had significantly less uterine activity than matched nulliparae but a similar profile to that in the matched multiparae. Progress of labour into the active phase in the previous pregnancy reduces the uterine activity profile in subsequent labour. Women who had had a vaginal delivery either before or after the CS (group C) exhibited uterine activity profiles similar to multiparae, suggesting that an intact scar did not affect the uterine function.