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 measures 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.