Cervical contractions: the response of the cervix to oxytocic stimulation in the latent phase of labour

Abstract

Objective To assess the cervical response to myometrial activity in early labour. Design Prospective observational study. Subjects Women requiring oxytocin stimulation in induced and spontaneous labours. Setting A teaching hospital in Birmingham. Main outcome measures Simultaneous comparison of the cervical response to myometrial contractions was made on a cycle by cycle basis to deduce the properties of the cervix in early labour. Results Sixty‐seven patients have been monitored, of whom 63 had satisfactory cervimetry data. Thirty (47.6%) women exhibited cervical contractions in response to myometrial activity. This response was only observed at dilatations up to 4 cm. The change in behaviour coincides with the transition from latent to active phases of dilatation. The length of the latent phase of labour was significantly longer in those women who exhibited cervical contractions (P<0.001), although the active phase was similar in the two groups (P>0.1). The group without cervical contractions exhibited a greater degree of efface‐ment (P<0.05) and tended to have more dilated cervices (P<0.01) than those who showed cervical contractions. Conclusions It is possible for the cervix to contract in early labour. This response may be the result of incomplete preparation of the cervix for the process of dilatation, and is seen during what is recognised as the latent phase in those women in whom the cervix is uneffaced and undilated. These properties of the cervix may explain the poor results obtained from oxytocin stimulation of labour in the latent phase.

Activity of smooth muscles in human cervix and uterus

“…The present study supports the findings of some clinical observations [3][4][5][6] and previous electromyographic studies on a few cases only [8] that in humans the smooth muscles in the cervix act independently of those in the uterine corpus. We studied the situation at the onset of induced labour (after amniotomy), in relatively unripe cervices, i.e.…”

“…Tel./fax: + 386 61 315328; e-mail: marjan. pajntar@kclj.si that the cervix in humans constricts, constricts rhythmically and constricts independently of the corpus [3][4][5][6]. This activity can be assessed reliably by electromyography.…”

Active management of labour revisited

“…Of course, resistance is a function of the cervix in a woman who is not in labour, but extrapolation to an intrapartum role in dystocia is presumptive. Cervical contractions do occur in response to oxytocin, but in the uneffaced cervix 20 . The failure to recognise the importance of effacement and the different effacement‐dilatation sequences in multiparous and nulliparous women raises questions about the relevance of the measurements from which the concept of cervical resistance in labour is derived.…”

Cervical contractions: the response of the cervix to oxytocic stimulation in the latent phase of labour

“…Sir I would like to thank Drs Cahill and Fox for their interest in this work (Olah et al 1993). It is gratifying that this study has stimulated some thought on the problems of failure to progress in the first stage of labour.…”