Does a combination of fluid restriction and the use of oxytocin in a pulsatile fashion (intermittent boluses) for women requiring an induction, result in a reduction in the duration of labour, defined by the commencement of oxytocin until the birth of the neonate, when compared to a regime of fluid restriction with continuous oxytocin?
Combined pulsatile oxytocin and fluid restriction study: A randomised controlled trial of women requiring an induction of labour, comparing pulsatile oxytocin to continuous oxytocin and the effect that this has on the duration of labour, as defined by the commencement of oxytocin until the birth of the neonate.
Northern Health
412 participants
Mar 6, 2023
Interventional
Conditions
Summary
At The Northern Hospital, on average, 1 in 4 women will require their labour to be induced with oxytocin. Currently, this medication is given as a continuous infusion intravenously, with the amount of oxytocin given increased every 30 minutes until 4 uterine contractions within 10 minutes are regularly observed. However, the body normally releases this hormone in a 'pulsatile' or intermittent fashion every 3-5 minutes during labour, rather then releasing it continuously. The hypothesis being tested is whether giving oxytocin intravenously in a pulsatile fashion, which mimicks the physiological process, leads to better obstetric outcomes, in particular, a shorter duration of labour, more successful vaginal deliveries, less postpartum haemorrhage and less requirement for epidural analgesia, when compared to the current process of providing oxytocin in a continuous fashion. This hypothesis will be tested by a randomised controlled trial of 412 participants, Half of the participants will be randomised to continous infusion of oxytocin, whereas the other half will be randomised to pulsatile oxytocin. The primary outcome of interest will be the duration of labour as defined by the commencement of oxytocin, until the birth of the neonate.
Eligibility
Inclusion Criteria13
- Any of the indications for induction of labour as per institutional policy including the following:
- Diabetes (Type I, Type II, gestational diabetes, which is poorly controlled)
- Hypertension
- Pre-eclampsia
- Prolonged pregnancy defined as being greater than 41 weeks and 3 days
- Term prolonged rupture of membranes
- Reduced fetal movements +/- non-reassuring CTG
- Past history of fetal death in utero
- Chorioamnionitis
- Low PAPP-A
- Advanced maternal age (defined as greater than or equal to 40 years of age)
- Blood group isoimmunisation
- Suspected intrauterine growth restriction
Exclusion Criteria6
- Age less than 18 years
- Women who do not have the mental and/or legal capacity to consent
- Fetal presentation other than cephalic
- Gestational age < 37 weeks
- Multiple pregnancy
- Augmentation of labour
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Interventions
Pregnant females who require an induction and/or augmentation of their labour, will be randomised to either an intravenous continuous oxytocin infusion (which is commenced at 2 mls/hour from a stock solution of 500 mls of Hartmann's solution containing 30 IU of oxytocin), with the rate increased every 30 minutes until there are 4 uterine contractions within 10 minutes, as per Safer Care Victoria's maternity e-handbook, as opposed to the same concentration of oxytocin, but given in a pulsatile fashion. As per Institutional policy and as per Safer Care Victoria's maternity e-handbook, using a stock solution of 10 IU oxytocin in 1000 ml crystalloid, oxytocin is commenced at an initial infusion rate of 12 ml/hr, which is then increased in a stepwise fashion, every 30 minutes, until 4 uterine contractions occur within 10 minutes. The maximum allowable rate of infusion to allow the uterus to contract 4 times within 10 minutes is 192 ml/hr. For this study, the stock solution of oxytocin to be used is the Queensland concentration of 30 IU oxytocin in 500 ml crystalloid, which is 6x greater the concentration of the Victorian stock solution. Therefore, for the continuous arm of the study, rather than initially commencing at 12 ml/hr, the equivalent volume would be 2 ml/hr and the maximum allowable rate of infusion would be 32 ml/hr. For the pulsatile arm of the study, rather than a continuous infusion of 12 ml/hr the equivalent 'pulse' is 0.1 ml every 3 minutes. For the maximum allowable rate of 32 ml/hr, this equates to a 'pulse' of 1.6 ml every 3 minutes. A table showing the rates of infusion for both the continuous and pulsatile arms of the study will be provided to the midwife caring for the woman having an induction of labour and the table will also be attached to the pump used to deliver the oxytocin in either a continuous or pulsatile fashion. The initial programming of the pumps and education of the midwife caring for the woman having an induction of labour, will be provided by Darren Lowen, after the participant has been consented to the study. This will ensure that the intervention protocol is adopted and all participant's medical records will be audited to confirm that this is the case.
Locations(1)
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ACTRN12623000238673