Non-invasive intrapartum fetal ECG: preliminary report Myles J.O. Taylor, a Matthew J. Thomas, b Mark J. Smith, b Salome Oseku-Afful, a Nicholas M. Fisk, a Andrew R. Green, b Sara Paterson-Brown, a Helena M. Gardiner a Objectives To obtain fetal heart rate, detailed fetal electrocardiography (fECG) signals and uterine contrac- tions during labour using a single device. Design Prospective observational study. Setting Delivery suite at a tertiary referral hospital, London, UK. Population Fifteen patients at median gestation of 39 weeks (range 24–41) were recruited at median cervical dilatation of 4.0 cm (range 0–10) of whom 8/15 (53%) had intact amniotic membranes. Methods Using 12 abdominally sited electrodes, we recorded the composite abdominal signal in pregnancies intrapartum. The recorded data were analysed off-line using a blind signal separation technique. Main outcome measures Success of signal separation and f ECG time intervals. Results Successful fECG signal acquisition was achieved in 12/15 (80%) patients and an averaged fECG waveform acquired. In these patients, P and QRS waves were seen in all cases, and T waves in 11/12 (92%). True beat-to-beat heart rate (HR) was displayed and measures of its variability obtained. The mother’s ECG and uterine electrical activity, shown to match tocographically recorded uterine contractions, were also separated and displayed. Failure to acquire fECG in three cases was attributed to excessive abdominal muscular activity and electrical interference. Conclusions This study demonstrates a non-invasive technique that displays detailed intrapartum fECG waveforms, HR variability, maternal ECG and uterine contractions simultaneously, all in a single device and which avoids the potential risks of invasive monitoring with a fetal scalp electrode. INTRODUCTION Birth is a hazardous process. Intrapartum mortality in the UK is 1 in 1600 live births 1 and the risk of newborn encephalopathy secondary to intrapartum hypoxia, with its attendant risk of long term disability, 2 is greater at 1 in 260 births. 3 In the UK each damaged baby costs the Clinical Negligence Scheme for Trusts (CNST) approxi- mately £3.5 million, and the National Health Service currently has potential liabilities for clinical negligence of £6 billion (http://www.nhsla.com), two-thirds of which is in obstetrics. The widely held concept that intrapartum events account for a minority of brain injury at term has been challenged by a recent population-based study 4 where birth asphyxia was thought the likely cause of cerebral palsy in 28% and further supported by brain MRI and post- mortem examinations 5 where evidence of acute brain insult was seen in 77% of term infants with neonatal encepha- lopathy or seizures. Only 1% showed evidence of lesions predating the onset of labour thus highlighting the poten- tial impact of effective intrapartum monitoring. Current intrapartum monitoring uses either intermit- tent auscultation of the fetal heart or continuous elec- tronic monitoring by cardiotocography (CTG). CTG uses Doppler ultrasound to demonstrate a fetal heart rate which is not a true beat-to-beat heart rate but an average over three neighbouring beats, analysed to give baseline rate, baseline variability and periodic changes. Abnormal heart rate patterns indicative of fetal hypoxaemia prompt ob- stetric interventions such as caesarean section or assisted vaginal delivery to prevent birth asphyxia. The expectation that CTG monitoring would reduce the incidence of deaths or brain damage in labour has not been realised. 6,7 Prob- lems include the low reproducibility of CTG interpretation 8 and inadequate staff response to changes. 1 As CTG is re- corded from the labouring mother by cumbersome belts, technical problems occur frequently and resultant inade- quate quality traces lead to confusion of fetal with maternal heart rate and halving or doubling of fetal heart rates. The low predictive value of abnormal CTG traces for fetal acidemia is explained in part by the lack of a genuine beat-to-beat recording and any fetal electrocardiographic (fECG) waveform detail. Inadequate monitoring has been partly responsible for the rise in overall caesarean section rates BJOG: an International Journal of Obstetrics and Gynaecology August 2005, Vol. 112, pp. 1016–1021 D RCOG 2005 BJOG: an International Journal of Obstetrics and Gynaecology www.blackwellpublishing.com/bjog a Queen Charlotte’s and Chelsea Hospital and Division of Paediatrics, Obstetrics and Gynaecology, Faculty of Medicine, Imperial College, London, UK b Advanced Signal and Information Processing Group, QinetiQ, Malvern, Worcestershire, UK Correspondence: Mr M. J. O. Taylor, Royal Devon and Exeter, Hospital (Heavitree), Gladstone Road, Exeter, EX1 2ED, UK. DOI:10.1111/j.1471-0528.2005.00643.x