Table 1.

Descriptive statistics of the signal loss and values of differences MD, MAD, determined for the final set of recordings from the electrocardiography (FECG) and the ultrasound method (US), where the FHR signals were expressed as the original 250 ms measures, and as the values averaged over 2.5 s periods.

	FHR 250 ms						FHR 2.5 s
	Signal loss (%)		FECG-US (bpm)		FECG-US (ms)		Signal loss (%)		FECG-US (bpm)
	FECG	US	MD	MAD	MD	MAD	FECG	US	MD	MAD
Mean	1.80	4.53	−0.23	1.24	0.71	3.83	1.35	4.29	−0.09	0.71
SD	3.01	6.52	0.38	0.46	1.25	1.62	2.59	6.42	0.40	0.43
Median	0.60	0.95	−0.19	1.12	0.59	3.36	0.35	0.75	−0.05	0.58
Min	0.00	0.10	−1.29	0.50	−4.52	1.39	0.00	0.00	−1.50	0.23
Max	14.70	26.80	1.54	2.86	5.33	9.91	12.50	26.40	1.49	2.50