Table 2. Side effects and adverse maternal and perinatal outcomes.

	Group 1 (n=83)	Group 2 (n=82)	Group 3 (n=82)	p-value§
Arterial hypotension	0% (0/83)	0% (0/82)	0% (0/82)	*
Nausea	0% (0/83)	0% (0/82)	0% (0/82)	*
Vomiting	0% (0/83)	0% (0/82)	0% (0/82)	*
Pruritus	0% (0/83)	0% (0/82)	0% (0/82)	*
Respiratory depression	0% (0/83)	0% (0/82)	0% (0/82)	*
Fetal bradycardia	9.6% (8/83)	8.5% (7/82)	20.7% (17/82)	0.036
Apgar score <7 at 1st minute	44.6% (37/83)	17.1% (14/82)	22.0% (18/82)	<0.001
Need for neonatal oxygen therapy	0% (0/83)	0% (0/82)	6.1% (5/82)	0.016
Need for neonatal ICU	0% (0/83)	0% (0/82)	4.9% (4/82)	0.017

Group 1: analgesia performed in patients with cervical dilatation ≤4.0 cm; Group 2: analgesia performed in patients with cervical dilatation between 5.0 and 8.0 cm; Group 3: analgesia performed in patients with cervical dilatation ≥9.0 cm. ICU: intensive care unit; Chi-square ^§percentage (n/N); p<0.05. *It was not possible to calculate the p-value due to the absence of at least three cases in each group.