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 re...