Study design and details
The 36 articles included 35 RCTs and one pilot study, published between 1964 and 2018, across 21 different countries and included 8,285 births from 8,285 women and 8,285 babies. Twenty-nine (81%) were single-centre studies. Details about the type of AVBs evaluated in the studies is provided in Table 1. There were a total of 73 interventions and comparators (36 device intervention groups, 33 device comparator groups and four SVB comparator groups). Half of the papers (n=18, 50%) compared different types or techniques of ventouse devices. There were no studies with a Caesarean section comparator group.
Twenty-nine papers (81%) had two arms, each investigating a different device. A further two papers had three arms (ventouse-ventouse-forceps and ventouse-forceps-SVB). Four papers compared a device to SVB and the final paper was a single arm pilot study investigating the Odon Device.
Two of the RCTs (6%) referenced earlier preliminary work and two further papers (6%) referenced study protocols. One of these provided further detail about adherence, but none provided additional information about intervention descriptions, standardisation or expertise.