A randomised clinical trial of intrapartum fetal monitoring with computer analysis and alerts versus previously available monitoring

Abstract

Background: Intrapartum fetal hypoxia remains an important cause of death and permanent handicap and in a significant proportion of cases there is evidence of suboptimal care related to fetal surveillance. Cardiotocographic (CTG) monitoring remains the basis of intrapartum surveillance, but its interpretation by healthcare professionals lacks reproducibility and the technology has not been shown to improve clinically important outcomes. The addition of fetal electrocardiogram analysis has increased the potential to avoid adverse outcomes, but CTG interpretation remains its main weakness. A program for computerised analysis of intrapartum fetal signals, incorporating real-time alerts for healthcare professionals, has recently been developed. There is a need to determine whether this technology can result in better perinatal outcomes.

Methods/design: This is a multicentre randomised clinical trial. Inclusion criteria are: women aged ≥ 16 years, able to provide written informed consent, singleton pregnancies ≥ 36 weeks, cephalic presentation, no known major fetal malformations, in labour but excluding active second stage, planned for continuous CTG monitoring, and no known contra-indication for vaginal delivery. Eligible women will be randomised using a computer-generated randomisation sequence to one of the two arms: continuous computer analysis of fetal monitoring signals with real-time alerts (intervention arm) or continuous CTG monitoring as previously performed (control arm). Electrocardiographic monitoring and fetal scalp blood sampling will be available in both arms. The primary outcome measure is the incidence of fetal metabolic acidosis (umbilical artery pH < 7.05, BDecf > 12 mmol/L). Secondary outcome measures are: caesarean section and instrumental vaginal delivery rates, use of fetal blood sampling, 5-minute Apgar score < 7, neonatal intensive care unit admission, moderate and severe neonatal encephalopathy with a marker of hypoxia, perinatal death, rate of internal monitoring, tracing quality, and signal loss. Analysis will follow an intention to treat principle. Incidences of primary and secondary outcomes will be compared between groups. Assuming a reduction in metabolic acidosis from 2.8% to 1.8%, using a two-sided test with alpha = 0.05, power = 0.80, and 10% loss to follow-up, 8133 women need to be randomised.

Discussion: This study will provide evidence of the impact of intrapartum monitoring with computer analysis and real-time alerts on the incidence of adverse perinatal outcomes, intrapartum interventions and signal quality. (Current controlled trials ISRCTN42314164).