'Extended Balloon Catheter' Labour Induction; a Single Arm Pilot Trial'

Labour induction is indicated when the benefits to the mother and/or foetus of discontinuing the pregnancy outweigh the risks of awaiting spontaneous onset of labour. However, induction of labour is not without risk and the World Health Organisation recommends induction of labour be performed with a clear medical indication and when the expected benefits outweigh potential harms. Established indications for induction of labour include gestational age of 41 completed weeks or more, prelabour rupture of amniotic membranes, hypertensive disorders, maternal medical complications, foetal growth restriction, chorioamnionitis, multiple pregnancy, vaginal bleeding and other complications.

The ideal method for induction should be safe for both the mother and baby, cost effective and not require extensive monitoring. Trans-cervical extra-amniotic Foley catheter placement has been shown to be the safest method of labour induction with fewer maternal and neonatal side effects such as uterine hyperstimulation and changes in foetal heart rate during labour than prostaglandins or oxytocin. It has also been shown that there were no significant differences between caesarean and vaginal deliveries between Foley catheter, prostaglandins and oxytocin, although labour was shown to last longer after induction with Foley catheter than with prostaglandins and oxytocin. These factors can therefore potentially influence the women's preference for either method.

Foley catheter has generally been used for labour induction with an unfavourable cervix and once the cervix is favourable or the Foley method is unsuccessful, prostaglandins or oxytocin with amniotomy are used. In lower and middle income countries like Botswana where patient monitoring during induction of labour and labour is limited and mostly intermittent, mainly due to the limited or lack of monitoring devices to detect uterine hyperstimulation or foetal heart rate changes, a high patient to midwife ratio, and a high HIV prevalence, it may be preferable to avoid amniotomy and risks associated with hyperstimulation with exogenous oxytocin or prostaglandins. There are no randomized trials of Foley catheter induction with a favourable cervix reported in the Cochrane review of mechanical methods of labour induction. To optimize the likelihood of delivery without recourse to amniotomy and oxytocin or prostaglandins, 'extended balloon catheter' has been proposed as a method of continuing induction and augmentation with a Foley catheter rather than switching to other methods.

The purpose of this proposed single arm pilot trial was to test this novel idea of using 'extended balloon catheter' for induction of labour in women with favourable cervix in Botswana, and assess its effectiveness, safety to both the mother and baby as well as patient satisfaction with the procedure. Findings from this study will guide clinical protocols on how to utilize the safest available option for optimal maternal and neonatal outcomes as well as offer options and evidence for counselling women for whom prostaglandins or oxytocin are contraindicated or for use with caution in Botswana and elsewhere.

Inclusion criteria

• Women 18 years or older without serious morbidity due for labour induction, who give consent to participate.
• Cervix considered too far dilated to retain a single balloon, or single balloon has fallen out while not yet in labour.
• Bishop score of equal or more than 7.
• Nulliparous and multiparous
• Singleton and cephalic
• Gestation >37+0 weeks
• Estimated fetal weight <4kg

Exclusion criteria

• Previous caesarean delivery
• Very urgent labour induction indications (eg eclampsia, preeclampsia with severe features)
• Ruptured membranes