Intrapartum CTG and Partogram Characteristics: Can They Predict Neonatal Outcomes?

Intrapartum hypoxia-ischemia is a significant contributor to the global burden of perinatal death and brain injury. Therapeutic hypothermia has brought an improvement in outcomes for those affected by neonatal encephalopathy due to hypoxia-ischemia, but the consequences are still significant and often last a lifetime. Therefore, prevention of in utero hypoxia-ischemia is imperative. Through an understanding of the pathophysiology of intrapartum hypoxia ischemia we may learn to predict and prevent congenital brain injury.

Evidence from physiological studies suggests that increased uterine activity may be part of that pathophysiology. Frequent uterine contractions (tachysystole) are sometimes mentioned as a risk factor for HIE, but their significance has not been well-defined nor universally accepted.

Research challenges contribute to this persistent ambiguity. Owing to inconsistent detection and frequent artefacts, measuring uterine contractions with commonplace technology is problematic. To demonstrate the reliability of our methods, a computer algorithm to interpret recordings of uterine activity was developed. A major aim of the algorithm’s design was to increase overall accuracy by ignoring poorly recorded sections. In this thesis, that algorithm is shown to approximate interpretation of uterine activity recordings by trained researchers.

The algorithm was then employed as part of a case-control study of risk factors for HIE. The results of that study confirmed that the risk of HIE was increased in association with higher uterine contraction rates. Furthermore, the effect of increased contraction frequency was augmented by slow cervical dilation.

HIE is rare. Partly due to its rarity, it is difficult to predict accurately. The results presented in this thesis go some way towards explaining its aetiology, but further advancements will be needed before it can be predicted early enough and with sufficient precision that it may be prevented.