Accelerated Titration of Oxytocin for Nulliparous Patients With Labour Dystocia: ACTION Pilot Study

Overview

The ultimate objective is to test the hypothesis that an 'accelerated titration' protocol for labour augmentation with oxytocin reduces the risk of caesarean births relative to a 'gradual titration' protocol. The aims of this pilot feasibility are: 1. To assess the feasibility of a large multi-centre randomized control trial comparing the two above oxytocin protocols (accelerated titration versus gradual titration for correction of dystocia). 2. More specifically, to identify potential challenges in the study implementation, particularly with respect to patient recruitment, randomization, blinding, and compliance/adherence to the labour management guidelines and study protocols. 3. To obtain preliminary data on the acceptability of the accelerated oxytocin titration protocol among obstetrical providers and participants.

There has been a steady increase in the rate of Caesarean births in Canada and worldwide. Almost half of all primary caesarean sections are performed for labour dystocia - when labour is abnormally slow or when there is no further progression in cervical dilatation. When dystocia occurs, oxytocin is used to increase the frequency and intensity of uterine contractions, with the goal of achieving full cervical dilatation and a vaginal birth. The actual dose required to produce a clinical response (progressive cervical dilatation) varies greatly from patient to patient. There is a wide range of oxytocin regimens currently in use. They may be broadly categorized as being of two types: 1) those involving a gradual titration of oxytocin dose (or 'low dose') and 2) those with accelerated oxytocin titration (also called 'high dose'). In fact, the frequently used terms 'low dose' and 'high dose' are to a certain extent misnomers. Both protocols titrate oxytocin dose to achieve the desired 'physiological frequency' of uterine contractions (usually 4 to 5 contractions in a 10 minute interval) that are normally sufficient to result in progressive labour. Thus, the target dose should, theoretically, be identical and independent of the rate of increase of oxytocin. These protocols differ mainly in the rate at which the desired physiologic response is achieved. While most patients achieve a response to stimulation at oxytocin concentrations between 4 and 10 mU per minute, a proportion of nulliparae require higher doses of oxytocin. Accelerated titration protocols are also frequently associated with a higher maximum concentration of oxytocin. While, most Canadian birthing centres currently follow a 'gradual titration' or 'low dose' protocol, there is evidence that 'accelerated titration' or 'high dose' protocols may be more effective in correcting dystocia and in preventing caesarean section. It is postulated that by more rapidly progressing to the required therapeutic dose, cervical dilatation is achieved more rapidly, the likelihood of a spontaneous vaginal birth is increased, and the risk of occurrence of complications resulting from prolonged labour (such as infection and maternal fatigue) is reduced.