Introduction: Why is intrapartum foetal monitoring necessary - Impact on outcomes and interventions

Abstract

Maintaining maternal oxygen supply is essential for foetal life, and labour constitutes an increased challenge to this. Good clinical judgement is required to evaluate the signs of reduced foetal oxygenation, to diagnose the underlying cause, to judge the reversibility of the condition and to determine the best timing for delivery. The main aim of intrapartum foetal monitoring is to identify foetuses that are being inadequately oxygenated, enabling appropriate action before the occurrence of injury. It is also to provide reassurance in cases of adequate foetal oxygenation, and thus to avoid unnecessary obstetric intervention. Poor foetal oxygenation is diagnosed by documenting metabolic acidosis in the umbilical cord immediately after birth or in the newborn circulation during the first minutes of life. However, most newborns recover quickly, and they do not develop relevant short- or long-term complications. Hypoxic-ischaemic encephalopathy is the short-term neurological dysfunction caused by inadequate intrapartum foetal oxygenation, and cerebral palsy of the spastic quadriplegic or dyskinetic types is the long-term neurological complication most commonly associated with it. Although there is insufficient evidence from randomised controlled trials to demonstrate that any form of intrapartum foetal monitoring reduces the incidence of adverse outcomes, reports from the clinical setting have documented a decrease in metabolic acidosis, hypoxic-ischaemic encephalopathy and intrapartum death over the last decades. It may be difficult to demonstrate the benefit of diagnostic techniques in complex environments such as the labour ward, but a reduction in the incidence of adverse clinical outcomes constitutes important evidence that intrapartum foetal monitoring makes a difference.

Keywords: cardiotocography; foetal; foetal oxygenation; heart rate; monitoring; physiologic.