Nifedipine-Induced Changes in the Electrohysterogram of Preterm Contractions: Feasibility in Clinical Practice

Table 2

Shift of PSD peak frequency.

Group 1^1	Before nifedipine (Subgroup  1.1)	15 minutes after nifedipine (subgroup 1.2)	P-value
PDS peak frequency (Hz)	0.367±0.061	0.340±0.040
	0.415±0.046	0.375±0.051
	0.424±0.079	0.405±0.021
Mean	0.402±0.025	0.373±0.026	.043^∗
Group 2^2	Within 24 hours after starting nifedipine (subgroup 2.1)	1 day after finishing nifedipine (subgroup 2.2)	P-value
PDS peak frequency (Hz)	0.390±0.035	0.371±0.058
	0.436±0.046	0.403±0.074
	0.434±0.047	0.403±0.041
Mean	0.42±0.021	0.392±0.015	.024^∗
Group 3^3	Patients delivering after 1 week after start nifedipine (subgroup 3.1)	Patients delivering within 1 week after start nifedipine (subgroup 3.2)	P-value
PDS peak frequency (Hz)	0.340±0.040	0.407±0.065
	0.375±0.051	0.380±0.055
	0.405±0.021	0.434±0.047
	0.436±0.046
	0.390±0.035
Mean	0.389±0.031	0.407±0.022	.458^∗∗

1 = patient 1–3 (Table 1)
2 = patient 4–6 (Table 1)
3 = patient 1–8 (Table 1)
∗calculation by 2-tailed paired student t test
∗∗calculation by 2-tailed unpaired student t-test.