The most important issue is most likely the human factor. Studies have shown that not only recognition of abnormal CTG patterns seems difficult but also of taken the correct action or taken actions at all [6, 7]. These include, among others, the lack of correction of a poor-quality CTG tracing, no follow-up after a first fetal scalp blood sample (FBS), increase in oxytocin dose instead of stopping it, and time delay in delivering the baby [7]. Also in some cases monitored with the relatively new STAN technology, it appeared that so-called false-negative STAN cases were not false-negative at all but were due to obstetricians who did not know the STAN guidelines and/or did not take the proper action [8]. So, the human factor may well be the most important limiting factor regarding CTG monitoring.

This should also be taken into account when discussing the use of so-called adjunct technologies. Many colleagues seem to interpret CTG patterns with only two options in mind: everything is fine with the baby (normal CTG), or immediate action should be taken (abnormal CTG), ignoring the fact that the majority of patterns are in between, i.e., “suspicious” [9]. Additional information on the fetal condition may be obtained using adjunct technologies, but these are usually forgotten or not implemented locally. Actions that may be taken in case of suspicious or abnormal CTG patterns are:

In case of external CTG, the Doppler device may record the maternal pulse rate, instead of the fetal heart rate. This may occur especially in case of maternal obesity or positional changes and occurs especially during the second stage of labor, when maternal heart rate may reach fetal values (Fig. 5.2). In this context, it has been found that over two-thirds of accelerations occurring during the second stage are from maternal origin [10]. Insertion of the maternal heart rate occurs also frequently after the birth of the first twin, after which the device may start recording the maternal pulse since the position of fetus-2 is likely to have changed (Fig. 5.2). Modern CTG equipment has the option to monitor the mother simultaneously, and this modus should be used in all cases of external CTG monitoring.

In the recent new FIGO guidelines on intrapartum fetal monitoring, the different adjunct technologies have been summarized [11].

Fetal blood sampling is only being practiced in a few mostly Northern European countries, countries with the lowest CD rates in the Western world. Randomized controlled trials (RCT) in the past have shown that FBS results in a lower incidence of CD and neonatal seizures as compared to the use of CTG monitoring only. However, in these trials, both were randomized against intermittent auscultation and were not compared directly. In the only RCT in which intermittent auscultation and CTG monitoring with or without additional FBS were compared, there were no differences in perinatal outcome [12]. CDs were least frequent in the intermittent auscultation group (6 %), as compared to 18 % in the CTG arm (significantly higher) and 11 % in the CTG/FBS arm. The latter was not significantly different from the CTG-only arm, and therefore, many clinicians have concluded that FBS does not reduce the CD rate. However, in this trial only 690 cases altogether were included. So, there is definitely the need for a large RCT comparing both approaches.

Digital stimulation in case of a suspicious CTG with reduced variability may distinguish between poor or adequate fetal health. A normalization of the pattern is associated with a normal fetal pH, but no additional information is obtained in the absence of a fetal reaction. This simple procedure should be used in all units, since it provides additional information in a considerable number of cases and it reduces the need for FBS with about 50 %.

ST(AN) technology cannot be applied in case of an abnormal CTG, since it has to be started beforehand. European RCTs have shown that STAN results in a lower need for FBS, a lower incidence of instrumental deliveries, and a nonsignificant reduction of metabolic acidosis at birth.

Many abnormal CTG patterns are due to oxytocin overstimulation [7]. Adequate monitoring of contractions is therefore essential. In case of overstimulation, the first action should be to stop oxytocin (stop and not halving the dose!). However, oxytocin has a half-life of about 15 min and to stop oxytocin may therefore not be sufficient. The use of a tocolytic drug (beta-mimetic or oxytocin receptor blocker) does significantly reduce contractions within a few minutes ([13]; Fig. 5.3). After normalization of the CTG pattern, the start of spontaneous contractions may be awaited.

Amnioinfusion, the introduction of about 250 ml saline in the amniotic cavity through an intrauterine catheter, significantly reduces the incidence of decelerations and the incidence of CDs ([14]; Fig. 5.4). Such effects may be found in about half of the cases, especially in case of so-called variable decelerations.

So, in case of suspicious/abnormal CTG traces, several actions may be taken before deciding if an instrumental delivery is indicated, provided that there are no emergency situations. The “art” of obstetrics seems to have disappeared in many units and should be revitalized.