Comparison 1.

Aspirin versus placebo for perineal pain

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Adequate pain relief as reported by the woman	13	1001	Risk Ratio (M‐H, Fixed, 95% CI)	2.03 [1.69, 2.42]
1.1 300 mg aspirin	1	53	Risk Ratio (M‐H, Fixed, 95% CI)	2.6 [0.36, 18.88]
1.2 500 to 650 mg aspirin	11	800	Risk Ratio (M‐H, Fixed, 95% CI)	1.98 [1.64, 2.39]
1.3 900 mg aspirin	1	40	Risk Ratio (M‐H, Fixed, 95% CI)	1.83 [0.84, 3.99]
1.4 1200 mg aspirin	3	108	Risk Ratio (M‐H, Fixed, 95% CI)	2.75 [1.25, 6.06]
2 Need for additional pain relief	10	744	Risk Ratio (M‐H, Fixed, 95% CI)	0.25 [0.17, 0.37]
2.1 300 mg aspirin	1	53	Risk Ratio (M‐H, Fixed, 95% CI)	0.16 [0.03, 0.79]
2.2 500 to 650 mg aspirin	9	569	Risk Ratio (M‐H, Fixed, 95% CI)	0.27 [0.17, 0.41]
2.3 900 mg aspirin	1	40	Risk Ratio (M‐H, Fixed, 95% CI)	0.14 [0.01, 2.60]
2.4 1200 mg aspirin	2	82	Risk Ratio (M‐H, Fixed, 95% CI)	0.20 [0.06, 0.70]
3 Maternal adverse effects	14	1067	Risk Ratio (M‐H, Fixed, 95% CI)	1.08 [0.57, 2.06]
3.1 300 mg aspirin	1	53	Risk Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
3.2 500 to 650 mg aspirin	13	892	Risk Ratio (M‐H, Fixed, 95% CI)	1.13 [0.51, 2.53]
3.3 900 mg aspirin	1	40	Risk Ratio (M‐H, Fixed, 95% CI)	2.5 [0.55, 11.41]
3.4 1200 mg aspirin	2	82	Risk Ratio (M‐H, Fixed, 95% CI)	0.10 [0.01, 1.80]