Comparison 1. Remifentanil (PCA) versus another opioid (IV/IM).

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Satisfaction with pain relief	4	216	Std. Mean Difference (IV, Random, 95% CI)	2.11 [0.72, 3.49]
2 Respiratory depression (< 8 breaths/min)	1		Risk Ratio (M‐H, Random, 95% CI)	Totals not selected
3 Oxygen desaturation (SpO2 < 95%)	2	113	Risk Ratio (M‐H, Random, 95% CI)	0.48 [0.00, 47.37]
4 Nausea (and vomiting)	4	216	Risk Ratio (M‐H, Random, 95% CI)	0.54 [0.29, 0.99]
5 Vomiting	1		Risk Ratio (M‐H, Random, 95% CI)	Totals not selected
6 Pruritus	2	156	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
7 Sedation (1 h)	1		Mean Difference (IV, Random, 95% CI)	Totals not selected
8 Apgar score < 7 at 5 min	1		Risk Ratio (M‐H, Random, 95% CI)	Totals not selected
9 Apgar score at 5 min	1		Mean Difference (IV, Random, 95% CI)	Totals not selected
10 FHR/CTG abnormalities, non‐reassuring fetal status	2	156	Risk Ratio (M‐H, Random, 95% CI)	0.30 [0.10, 0.90]
11 Pain intensity 'early' (1 h)	3	180	Std. Mean Difference (IV, Random, 95% CI)	‐1.58 [‐2.69, ‐0.48]
12 Pain intensity 'late' (2 h)	1		Mean Difference (IV, Random, 95% CI)	Totals not selected
13 Additional analgesia required (escape analgesia)	3	190	Risk Ratio (M‐H, Random, 95% CI)	0.57 [0.40, 0.81]
14 Rate of caesarean delivery	4	215	Risk Ratio (M‐H, Random, 95% CI)	0.70 [0.34, 1.41]
15 Rate of assisted birth	4	215	Risk Ratio (M‐H, Random, 95% CI)	0.82 [0.32, 2.09]
16 Augmented labour	3	190	Risk Ratio (M‐H, Random, 95% CI)	0.97 [0.72, 1.29]
17 Breastfeeding initiation (feeding difficulties)	1		Risk Ratio (M‐H, Random, 95% CI)	Totals not selected