ST waveform analysis versus cardiotocography alone for intrapartum fetal monitoring: a systematic review and meta‐analysis of randomized trials

Abstract

Absolute effects of ST waveform analysis were minor, and the clinical significance of the observed reduction in metabolic acidosis is questioned. There is not enough evidence to justify the use of ST waveform analysis in contemporary obstetrics.

STAN technology, surrogate outcomes and possible sources of bias

“…We investigated several outcomes in our review, and two (risk of metabolic acidosis and operative vaginal delivery) showed statistically significant differences in favor of STAN. (3). Two other high quality meta-analyses were published almost simultaneously (4,5), and neither reported significant differences in rates of metabolic acidosis.…”

Why did the authors perform a meta‐analysis of studies with primary endpoints they consider clinically unimportant?

“…Their conclusions, however, are based on presuppositions that are highly questionable. The systematic review by Blix et al (1) was prompted by a recently published American randomized controlled trial (RCT) on STAN (3). However, this RCT was performed on a predominantly low-risk population with guidelines for CTG interpretation and threshold for STAN intervention different from those applied in all European RCTs and in clinical use.…”

The electrical heart axis and ST events in fetal monitoring: A post-hoc analysis following a multicentre randomised controlled trial

“…However, subsequent multicentre trials, including the recently published large American STAN trial, could not reproduce these initial findings [5–9]. Recent meta-analyses show conflicting results regarding the decrease in metabolic acidosis, which indicates the need for more research [8,10–13]. Meanwhile, Kwee et al [14] reported that the STAN monitor gives as many ST events in cases of proven uncompromised fetal condition as in situations with deteriorating fetal condition.…”