Comparison 18. Systemic opioids (E) vs regional anaesthesia (C).

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Cephalic presentation at birth (primary)	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
2 Failure to achieve cephalic vaginal birth (composite outcome: caesarean section + vaginal breech birth)	1	95	Risk Ratio (M‐H, Random, 95% CI)	1.18 [0.90, 1.54]
3 Caesarean section (primary)	1	95	Risk Ratio (M‐H, Random, 95% CI)	1.18 [0.90, 1.54]
4 Fetal bradycardia (primary)	1	94	Risk Ratio (M‐H, Random, 95% CI)	0.71 [0.24, 2.09]
5 Failed external cephalic version	1	95	Risk Ratio (M‐H, Random, 95% CI)	1.29 [0.93, 1.80]
6 Difficult external cephalic version	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
7 Maternal palpitations	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
8 Maternal headaches	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
9 Maternal hypotension	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
10 Operative vaginal birth	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
11 Maternal mortality	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
12 Maternal morbidity	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
13 Perinatal mortality	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
14 Perinatal morbidity	0	0	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]