ABSTRACT

Please cite this paper as: Cleal J, Thomas M, Hanson M, Paterson-Brown S, Gardiner H, Green L. Noninvasive fetal electrocardiography following intermittent umbilical cord occlusion in the preterm ovine fetus. BJOG 2010;117:438–444.

Objective To investigate whether a noninvasive fetal electrocardiography (fECG) system can identify cardiovascular responses to fetal hypoxaemia and validate the results using standard invasive fECG monitoring techniques.

Design Prospective cohort study.

Setting Biological research facilities at The University of Southampton.

Population or Sample Late gestation ovine fetuses; n = 5.

Methods Five fetal lambs underwent implantation of vascular catheters, umbilical cord occluder and invasive ECG chest electrodes under general anaesthesia (3% halothane/O₂) at 119 days of gestation (term 147 days of gestation). After 5 days of recovery blood pressure, blood gases, glucose and pH were monitored. At 124 and 125 days of gestation following a 10-minute baseline period a 90-second cord occlusion was applied. Noninvasive fetal ECG was recorded from maternal transabdominal electrodes using advanced signal-processing techniques, concurrently with invasive fECG recordings.

Main outcome measures Comparison of T:QRS ratios of the ECG waveform from noninvasive and invasive fECG monitoring systems.

Results Our fECG monitoring system is able to demonstrate changes in waveforms during periods of hypoxaemia similar to those obtained invasively, which could indicate fetal distress.

Conclusions These findings may indicate a future use for noninvasive electrocardiography during human fetal monitoring both before and during labour in term and preterm pregnancies.