STAN and the new FIGO consensus guidelines on intrapartum CTG monitoring

The International Federation of Gynecology and Obstetrics (FIGO) presented in 2015 an updated intrapartum CTG classification system to replace the system from 1987. The CTG classification used in the STAN CTG+ST interpretation algorithm is basically a modified version of the FIGO 1987 classification system. The new FIGO system differs from the CTG classification used with STAN in the definitions of a normal FHR baseline, normal variability, variable decelerations, repetitiveness of decelerations, and the number of CTG classes. The new FIGO system is a 3-tier system where the pre-terminal CTG class has been omitted and with no specific outlining of silent patterns.

In Sweden, the Swedish Society of Obstetrics and Gynecology (SSOG) has in 2017 together with the Swedish Association of Midwives introduced a FIGO-approached classification system. Both the FIGO and the SSOG systems are consensus guidelines created by expert committees. Due to the lack of evidence for improved, or at least unchanged, fetal and maternal outcomes with the new classification systems, objections have been raised against their introductions without prior clinical safety studies.

It is a hitherto unanswered question whether the new FIGO system can be used in the STAN CTG+ST interpretation algorithm. In an ongoing Swedish study, the statistical concordance and agreements in classifying the same series of CTG traces into normal/suspicious/pathological with the old and new classification systems are evaluated; similarly, the classification of ST events into significant or non-significant events are evaluated, and finally the impact on perinatal outcomes are evaluated. There are no results to be presented yet, but can be expected soon.

Neoventa Medical
Per Olofsson, Medical Advisor


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