The Effect of Two Midwives During the Second Stage of Labour to Reduce Severe Perineal Trauma (Oneplus) : A Multicentre, Randomized Controlled Trial in Sweden

In many high-income countries, severe perinatal trauma (SPT), affecting the anal sphincter muscle complex, has been on the rise over the last decade. However, effective strategies to prevent SPT are scarce. In randomized controlled trials, only perineal warm compresses and massage have shown benefit. Other cohort studies have shown that prevention models involving several components can decrease the occurrence of SPT, including a stepped-wedge design that reduced SPT from 3.3% to 3.0%. In Scandinavia, a preventive strategy called collegial assistance has been used to help prevent SPT. This strategy involves 2 midwiveswho assist thewoman in the second stage of labor, with the second midwife primarily focused on preventing SPT. The aim of this study was to compare the rate of SPT in pregnancies managed by collegial assistance versus a single midwife. This Oneplus study was a randomized, controlled, unmasked trial, conducted at 5 obstetric units in Sweden between December 10, 2018, and March 21, 2020. Included were adult women with uncomplicated singleton pregnancies at >37 weeks of gestation, who were carrying their first child or having their first vaginal birth after cesarean delivery. Excluded were women who had multiple pregnancies, had intrauterine fetal demise, were undergoing a planned cesarean section, or were at