Solution of Controversy in Fetal Heart Rate Patterns

Fetal well-being was estimated by the enlargement of maternal abdomen, palpation of fetus on the abdomen, maternal perception of fetal kicking, and listening to fetal heart sound with obstetric stethoscope, in old age. Antique diagnosis of fetal life was fetal QRS found on limb lead electrocardiogram (ECG) studied by Cremer, which was progressed to fetal ECG amplifier composed of vacuum tube recorded on maternal abdomen and fetal phonocardiogram (PCG) in 1950s studied by EH Hon, R Caldeyro-Barcia, K Maeda and others. Listening to amplified fetal heart sounds using microphone was a method of intrapartum fetal monitoring, but it was unable to detect fetal sinusoidal heart rate, then fetal monitoring was shifted to electronic fetal heart rate (FHR) monitoring, initially recorded with direct lead fetal ECG through maternal abdominal and uterine walls by R Caldeyro-Barcia in 1950s, then shifted to FHR tracing with scalp lead fetal ECG by EH Hon in 1960. Since the effect of uterine contraction was emphasized, simultaneous tracing of intrauterine pressure was common. Although perinatal mortality, neonatal asphyxia and cerebral palsy reduced after introduction of intrapartum FHR monitoring [13], there remained controversy on HR patterns in the electronic fetal monitoring (EFM) and cardiotokography (CTG).