A prospective randomised controlled trial of the Kiwi Omnicup versus conventional ventouse cups for vacuum-assisted vaginal delivery

Objective: To evaluate the performance and safety of the Kiwi Omnicup and compare it to conventional vacuum cups in routine clinical practice. Design: A randomised controlled trial of the Kiwi Omnicup versus conventional vacuum cups. Setting: Queen Charlotte's and Chelsea Hospital, a tertiary referral hospital in London from April 2001 to March 2004. Population: Women requiring assisted vaginal delivery by ventouse. Methods: Women were randomised to the Kiwi Omnicup (n = 206) or conventional vacuum cups (n = 198). Data regarding maternal demographics, labour, mode of delivery and maternal and neonatal outcome were collected. Main outcome measure: Failure of delivery with instrument of first choice. Results: The Kiwi Omnicup was less successful at delivery with instrument of first choice than the conventional ventouse, failure rate 30.1 versus 19.2% (RR 1.58; 95% CI 1.10-2.24). It was associated with a greater number of cup detachments (mean 0.68 compared with 0.28, with 44% compared with 18% having at least one detachment [P < 0.0001]). There was no difference in the incidence of severe maternal trauma, and there were no cases of serious neonatal injury. Conclusions: The Kiwi Omnicup is less successful than conventional ventouse in achieving vaginal delivery, but its safety profile is comparable.