Open AccessST waveform analysis versus cardiotocography alone for intrapartum fetal monitoring: a systematic review and meta‐analysis of randomized trials
Author(s) -
Blix Ellen,
Brurberg Kjetil G.,
Reierth Eirik,
Reinar Liv M.,
Øian Pål
Publication year - 2016
Publication title -
acta obstetricia et gynecologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 102
eISSN - 1600-0412
pISSN - 0001-6349
DOI - 10.1111/aogs.12828
Subject(s) - cardiotocography , medicine , randomized controlled trial , fetal monitoring , meta analysis , obstetrics , gynecology , fetus , pregnancy , genetics , biology
ST waveform analysis was introduced to reduce metabolic acidosis at birth and avoid unnecessary operative deliveries relative to conventional cardiotocography. Our objective was to quantify the efficacy of ST waveform analysis vs. cardiotocography and assess the quality of the evidence using the Grading of Recommendations Assessment, Development and Evaluation tool. Material and methods We identified randomized controlled trials through systematic literature searches and assessed included studies for risk of bias. Meta‐analyses were performed, calculating pooled risk ratio or peto odds ratio. We performed post hoc trial sequential analyses for selected outcomes to assess the risk of false‐positive results and the need for additional studies. Results Six randomized controlled trials were included in the meta‐analysis. ST waveform analysis was not associated with a reduction in operative deliveries due to fetal distress, but we observed a significantly lower rate of metabolic acidosis (peto odds ratio 0.64; 95% confidence interval 0.46–0.88). Accordingly, 401 women need to be monitored with ST waveform analysis to prevent one case of metabolic acidosis. No statistically significant effects were observed in other fetal or neonatal outcomes, except from fetal blood sampling (risk ratio 0.59; 95% confidence interval 0.45–0.79) and a minor reduction in the number of operative vaginal deliveries for all indications (risk ratio 0.92; 95% confidence interval 0.86–0.99). The quality of the evidence was high to moderate. Conclusions 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.