Cardiotocography alone is outdated and ST analysis is the way forward in fetal monitoring: FOR: Does the use of ST analysis in conjunction with cardiotocography improve perinatal outcome and/or reduce interventions for fetal distress?

GERARD H. A. VISSER, OBSTETRICIAN ANNEKE KWEE, OBSTETRICIAN, UNIVERSITY MEDICAL CENTRE UTRECHT, UTRECHT, THE NETHERLANDS W according to European randomised controlled trials (RCTs) the answer should be – at least partly – yes: there is a lower rate of instrumental deliveries and lower need for fetal blood sampling, whereas several meta-analyses are inconclusive regarding the effect on umbilical artery metabolic acidosis (Olofsson et al. Acta Obstet Gynecol Scand 2014;93:571–86). A recent large RCT in the USA did not show any differences between the ST arm and the conventially monitored arm of the trial, however (Belfort et al. NEJM 2015;373:632–41). Differences between the US trial and the European trials include a threetier instead of a four-tier cardiotocography (CTG) classification and an ST-action system, absence of fetal scalp sampling, and a very low institutional recruitment rate, despite the overall large size of the trial (on average nine inclusions per hospital per month, in contrast with 15–135 in the five European trials). The low inclusion rate of only two per week in large hospitals with many obstetricians and midwives working in the labour ward may have hampered adequate exposure to the new monitoring technique. Data from the European trials has shown that results in favour of ST analysis were more pronounced in the second half of the trials, which suggests a continuing learning process (Schuit AJOG 2013;209:394–5). Moreover, longitudinal data from several hospitals has shown that after the introduction of ST technology metabolic acidosis at birth fell over the course of several years by 50–75%, without an increase in instrumental deliveries (Visser et al. Acta Obstet Gynecol Scand 2014;93:539–43).