Foley catheter for induction of labour filled with 30mL or 60mL: A randomized controlled trial

One of the methods used to induce labour is the placement of a transcervical Foley catheter (FC). The aim of this randomized controlled study was to assess in term pregnant women with an unfavourable cervix, whether there is a difference in efficacy between the two most commonly used insufflation volumes of FC (30mL and 60mL).

Randomized controlled trial.

Women were randomized to induction of labour with a Foley catheter filled with 30mL or with 60mL. Primary outcome was delivery within eight hours after amniotomy. Secondary outcomes included the time interval between placement of the Foley and amniotomy, the mode of delivery, complications and neonatal outcomes. In total, 174 women (87 in each arm) were randomized. The number of deliveries within eight hours after amniotomy was not significantly different between the two groups (40.7% versus 48.83%, OR=0.71(CI; 0.39-1.3)). Sub-analysis showed that more multiparous women in the 60mL group delivered within eight hours (93.10% versus 65.22%, OR=7.2 (CI; 1.35-38.37)). For the nulliparous, the 30mL Foley catheter was associated with a higher caesarean section rate (31.75% versus 15.52% (OR 2.53; CI; 1.1-6.2)). The 60mL Foley catheter was also associated with a higher chance of spontaneous labour after placement (OR 2.35; CI; 1.1-5.1), a shorter time interval for cervical ripening (OR=4.5; CI: 1.2-16.7) and less blood loss. (p=0.002). The Foley catheter ruptured twelve times in the 60mL group whereas this did not happen once in the 30mL group. One case of umbilical cord prolapse was observed in the 60mL group. No differences in neonatal outcomes and patient satisfaction were seen.

For our primary outcome, no difference was observed between the Foley catheter balloon filled with 60mL and the one filled with 30mL. Yet, a Foley catheter filled with 60mL was associated in multiparous women with a higher rate of deliveries within eight hours after amniotomy and in nulliparous with a significantly lower caesarean section rate. These latest findings should be interpreted with cautious as underpowered.