Comparison 2. Larger gauge traumatic needles versus smaller gauge traumatic needles.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 PDPH larger gauge vs smaller gauge	10		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
1.1 23 G vs 25 G	1	53	Risk Ratio (M‐H, Random, 95% CI)	2.08 [0.20, 21.55]
1.2 25 G vs 27 G	4	1041	Risk Ratio (M‐H, Random, 95% CI)	1.82 [0.98, 3.39]
1.3 25 G vs 29 G	3	376	Risk Ratio (M‐H, Random, 95% CI)	2.13 [0.46, 9.78]
1.4 26 G vs 27 G	1	658	Risk Ratio (M‐H, Random, 95% CI)	6.47 [2.55, 16.43]
1.5 21 G vs 25 G	1	160	Risk Ratio (M‐H, Random, 95% CI)	0.86 [0.30, 2.44]
2 PDPH by type of surgery	10		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
2.1 Caesarean section	2	455	Risk Ratio (M‐H, Random, 95% CI)	1.28 [0.64, 2.57]
2.2 Orthopaedic surgeries	2	213	Risk Ratio (M‐H, Random, 95% CI)	0.99 [0.38, 2.58]
2.3 Other surgeries	6	1620	Risk Ratio (M‐H, Random, 95% CI)	2.94 [1.23, 7.03]
3 PDPH by age	10		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
3.1 No distinctions about age	8	2175	Risk Ratio (M‐H, Random, 95% CI)	2.09 [1.11, 3.95]
3.2 Only children	1	60	Risk Ratio (M‐H, Random, 95% CI)	3.0 [0.13, 70.83]
3.3 Only > 60 years	1	53	Risk Ratio (M‐H, Random, 95% CI)	2.08 [0.20, 21.55]
4 PDPH by position	7		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
4.1 Lateral position	5	859	Risk Ratio (M‐H, Random, 95% CI)	1.76 [0.98, 3.16]
4.2 Sitting position	2	584	Risk Ratio (M‐H, Random, 95% CI)	1.00 [0.64, 1.56]
5 AE: backache	3		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
6 Severe PDPH by gauge	6		Risk Difference (M‐H, Random, 95% CI)	Subtotals only
6.1 23 G vs 25 G	1	53	Risk Difference (M‐H, Random, 95% CI)	0.0 [‐0.07, 0.07]
6.2 25 G vs 27 G	3	815	Risk Difference (M‐H, Random, 95% CI)	0.00 [‐0.01, 0.01]
6.3 25 G vs 29 G	1	100	Risk Difference (M‐H, Random, 95% CI)	0.0 [‐0.04, 0.04]
6.4 21 G vs 25 G	1	160	Risk Difference (M‐H, Random, 95% CI)	0.0 [‐0.02, 0.02]
7 Any headache	3		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only