High Dose Versus Low Dose Oxytocin for Augmentation of Delayed Labour

The aim is to compare starting dose and increment of amount of oxytocin for augmentation of delayed labour to determine whether augmentation by high dose of oxytocin improves labour outcomes compared with a low dose of oxytocin, without effecting neonatal outcomes or birth experiences negatively.

Delay in labour, also described as poor progress, due to ineffective uterine contraction is a major problem in modern obstetric care and one of the main reasons for the increased rate of caesarean deliveries, in particular among nulliparous women. Infusion with synthetic oxytocin is a commonly used treatment of hypotonic uterine contractions. Despite the widespread use of oxytocin no consensus exists regarding the dosage of oxytocin, both starting dose and increment of amount of oxytocin.

In a randomized control trial conducted in six study centers/labour wards in Sweden, consenting nulliparous women in active phase of labour and with a defined delayed labour progress will be randomized to receive a regimen of either high or low dose of oxytocin. The expected outcome is a decreased caesarean section rate and increased rate of spontaneous vaginal delivery for women with high dose of oxytocin for augmentation, without affecting neonatal outcomes or childbirth experiences negatively.

Primary outcome is caesarean delivery rate. Secondary outcomes are Apgar score, need of neonatal intensive care, hyper-stimulation of contractions, spontaneous vaginal birth rate, length of labour, postpartum haemorrhage, sphincter lacerations, experienced labour pain, epidural analgesia and the women´s childbirth experience one month postpartum (assessed with Childbirth Experience Questionnaire). Based on a sample size calculation (α=0.05, β=0.80), 1045 women will be needed in each group. Analysis will be performed by the intention to treat.

Study results will contribute to establish good evidence-based routines regarding oxytocin treatment of delayed labour progress.

Inclusion criteria

• Healthy nulliparous women
• singleton pregnancy
• normal pregnancy
• cephalic presentation
• spontaneous onset of active labour
• at term (37 - 42weeks gestation)
• delay or arrest of active labour

Exclusion criteria

• Non-Swedish speaking women
• previous uterine surgery
• intrauterine growth retardation > - 22%
• malpresentation at time of inclusion
• intrapartal hemorrhage at time of inclusion
• nonreassuring fetal-heart pattern at time of inclusion
• meconium at time of inclusion