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Abstract
Currently, fetal heart rate (FHR) monitoring is the most widely used method for antepartum and intrapartum fetal surveillance. Antenatally, the introduction of FHR monitoring has been associated with a parallel decrease in perinatal mortality. However, a number of small scale controlled studies has failed to demonstrate the usefulness of FHR monitoring, both antenatally and intrapartum. Several possible explanations could be responsible for this apparent incongruous observation. Although FHR is normally easy to record, the quality of tracing is often sub-optimal, and adds to the complete lack of uniform interpretation shown in studies comparing interobserver and intra-observer variations. In addition, there is now an abundance of human observations and animal studies demonstrating that gestational age, in addition to the development of fetal behavioural status, are the most important factors that will alter FHR patterns under normal conditions and in response to hypoxaemia. It is also becoming evident that growth-restricted fetuses have inherent differences in FHR patterns when compared to normally-grown fetuses, possibly due to a delay in the maturation of the autonomic control of the fetal heart in response to chronic hypoxaemia. Therefore, in order to use electronic FHR monitoring, it is becoming necessary for the clinician to start learning about the physiology of the fetus, its changing evolution with advancing gestation, and the various ways these are represented in FHR tracings under stress or distress. With the development of computerized FHR analysis that virtually eliminates interobserver and intra-observer variation in interpretation, in addition to the knowkdge of the factors influencing FHR, it is now possible and timely to conduct a properly designed, large scale, randomized clinical trial to demonstrate whether or not both antenatal and intrapartum FHR monitoring can ultimately become useful tools in obstetrical practice.
Resume
La surveillance de la fréquence cardiaque du foetus (FCF) est actuellement la méthode de surveillance antepartum et intrapartum la plus fréquemment utilisée. Avant la naissance, on a lié l’adoption de la surveillance de la FCF à une diminution parallèle de la mortalité périnatale. Cependant, un certain nombre d’études contrôleés à petite échelle n’ont pas permis d’établir d’utilité de la surveillance de la FCF, à la fois avant la naissance et pendant l’intrapartum. On pourrait donner plusieurs explications de cette observation apparemment incongrue. Bien qu’il soit normalement facile d’enregistrer la FCF, la qualité du tracé est rarement optimale et elle favorise la totole absence d’uniformite d’interprétation constatée dans les études comparatives des écarts entre les observateurs et chez un même observateur. De plus, on dispose maintenant de nombreuses observations humaines et d’études animales révélant que l’âge gestationnel, ainsi que le développement des états comportementaux du foetus, constituent les plus importants facteurs d’altération des tracés de la FCF, dans des conditions normales et en réaction à l’hypoxémie. Il devient aussi évident que les foetus manifestant un retard de croissance présentent des différences inhérentes quant aux tracés de la FCF par comparaison avec les foetus dont la croissance est normale, peut-être en raison d’un retard de maturation du contrôle autonome du coeur foetal en réaction à une hypoxémie chronique. Ainsi, pour recourir à la surveillance électronique de la FCF, le clinicien doit se familiariser avec la physiologje du foetus, son évolution pendant le déroulement de la gestation et les divers moyens servant à représenter ces éléments dans les tracés de la FCF en cas de stress ou de souffrance. Grâce au perfectionnement de l’analyse informatisée de la FCF, qui élimine pratiquement les écarts d’interprétation entre les observateurs et chez le même observateur, en plus de la connaissance des facteurs ayant une incidence sur la FCF, il est maintenant possible d’effectuer rapidement un essai clinique randomisé, à grande échelle et bien conçu, pour vérifier si la surveillance de la FCF, à la fois avant la naissance et pendant l’intrapartum, pourra éventuellement devenir un outil utile pour exercer l’obstétrique.
Key Words
References
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Article info
Publication history
Accepted:
May 22,
1997
Received in revised form:
May 22,
1997
Received:
April 15,
1997
Identification
Copyright
© 1997 Published by Elsevier Inc.
