Comparison 5. Tramadol versus pethidine.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Pain intensity: women with poor pain relief	4	243	Risk Ratio (M-H, Fixed, 95% CI)	1.56 [1.10, 2.21]
2 Additional analgesia required	3	295	Risk Ratio (M-H, Random, 95% CI)	1.07 [0.60, 1.91]
3 Nausea and vomiting	6	454	Risk Ratio (M-H, Random, 95% CI)	0.97 [0.34, 2.76]
4 Maternal sleepiness	5	409	Risk Ratio (M-H, Random, 95% CI)	0.57 [0.33, 0.97]
5 Assisted vaginal delivery	3	260	Risk Ratio (M-H, Fixed, 95% CI)	0.56 [0.12, 2.56]
6 Caesarean section	3	260	Risk Ratio (M-H, Fixed, 95% CI)	0.71 [0.23, 2.18]
7 Low Apgar scores (≤ 7) at 1 and 5 minutes	2		Risk Ratio (M-H, Fixed, 95% CI)	Subtotals only
7.1 Low scores at 1 minute	2	250	Risk Ratio (M-H, Fixed, 95% CI)	0.0 [0.0, 0.0]
7.2 Low scores at 5 minutes	1	160	Risk Ratio (M-H, Fixed, 95% CI)	0.0 [0.0, 0.0]
8 Neonatal resuscitation	1	90	Risk Ratio (M-H, Fixed, 95% CI)	0.0 [0.0, 0.0]
9 Neonatal respiratory distress	1	59	Risk Ratio (M-H, Fixed, 95% CI)	2.26 [0.64, 7.89]
10 Admission to NICU	1	59	Risk Ratio (M-H, Fixed, 95% CI)	2.26 [0.64, 7.89]