Comparison 1. Intravenous versus intramuscular vitamin K.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Bleeding complications	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
1.1 0.2 mg IV versus 0.2 mg IM	1	52	Risk Ratio (M‐H, Fixed, 95% CI)	7.0 [0.38, 129.11]
1.2 0.2 mg IV versus 0.5 mg IM	1	54	Risk Ratio (M‐H, Fixed, 95% CI)	0.81 [0.20, 3.27]
1.3 Any IV Vitamin K (0.2 mg) versus any IM Vitamin K (0.2 mg and 0.5 mg)	1	80	Risk Ratio (M‐H, Fixed, 95% CI)	1.56 [0.38, 6.46]
2 Intraventricular hemorrhage > Grade II	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
2.1 0.2 mg IV versus 0.2 mg IM	1	52	Risk Ratio (M‐H, Fixed, 95% CI)	2.0 [0.19, 20.72]
2.2 0.2 mg IV versus 0.5 mg IM	1	54	Risk Ratio (M‐H, Fixed, 95% CI)	0.72 [0.13, 3.96]
2.3 Any IV Vitamin K (0.2 mg) versus any IM Vitamin K (0.2 mg and 0.5 mg)	1	80	Risk Ratio (M‐H, Fixed, 95% CI)	1.04 [0.20, 5.31]
3 Presence of PIVKA II at day 5	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
3.1 0.2 mg IV versus 0.2 mg IM	1	60	Risk Ratio (M‐H, Fixed, 95% CI)	1.52 [0.37, 6.23]
3.2 0.2 mg IV versus 0.5 mg IM	1	57	Risk Ratio (M‐H, Fixed, 95% CI)	2.07 [0.41, 10.43]
3.3 Any IV Vitamin K (0.2 mg) versus any IM Vitamin K (0.2 mg and 0.5 mg)	1	89	Risk Ratio (M‐H, Fixed, 95% CI)	1.74 [0.51, 6.00]
4 Presence of PIVKA II at day 25	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
4.1 0.2 mg IV versus 0.2 mg IM	1	52	Risk Ratio (M‐H, Fixed, 95% CI)	1.08 [0.07, 16.36]
4.2 0.2 mg IV versus 0.5 mg IM	1	51	Risk Ratio (M‐H, Fixed, 95% CI)	1.04 [0.07, 15.74]
4.3 Any IV Vitamin K (0.2 mg) versus any IM Vitamin K (0.2 mg and 0.5 mg)	1	78	Risk Ratio (M‐H, Fixed, 95% CI)	1.06 [0.10, 11.15]
5 Prolonged PT at day 5	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
5.1 0.2 mg IV versus 0.2 mg IM	1	63	Risk Ratio (M‐H, Fixed, 95% CI)	0.65 [0.24, 1.76]
5.2 0.2 mg IV versus 0.5 mg IM	1	60	Risk Ratio (M‐H, Fixed, 95% CI)	0.94 [0.30, 2.90]
5.3 Any IV Vitamin K (0.2 mg) versus any IM Vitamin K (0.2 mg and 0.5 mg)	1	92	Risk Ratio (M‐H, Fixed, 95% CI)	0.76 [0.30, 1.93]
6 Vitamin K1 epoxide detected (≥ 10 ng/mL on day 5)	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
6.1 0.2 mg IV versus 0.2 mg IM	1	61	Risk Ratio (M‐H, Fixed, 95% CI)	9.9 [0.56, 176.29]
6.2 0.2 mg IV versus 0.5 mg IM	1	58	Risk Ratio (M‐H, Fixed, 95% CI)	0.57 [0.19, 1.74]
6.3 Any IV Vitamin K (0.2 mg) versus any IM Vitamin K (0.2 mg and 0.5 mg)	1	90	Risk Ratio (M‐H, Fixed, 95% CI)	1.20 [0.38, 3.78]
7 Vitamin K1 epoxide detected (≥ 0.3 ng/mL on day 25)	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
7.1 0.2 mg IV versus 0.2 mg IM	1	52	Risk Ratio (M‐H, Fixed, 95% CI)	0.33 [0.01, 7.82]
7.2 0.2 mg IV versus 0.5 mg IM	1	54	Risk Ratio (M‐H, Fixed, 95% CI)	0.12 [0.01, 2.11]
7.3 Any IV Vitamin K (0.2 mg) versus any IM Vitamin K (0.2 mg and 0.5 mg)	1	80	Risk Ratio (M‐H, Fixed, 95% CI)	0.19 [0.01, 3.23]
8 Necrotizing enterocolitis	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
8.1 0.2 mg IV versus 0.2 mg IM	1	52	Risk Ratio (M‐H, Fixed, 95% CI)	1.0 [0.15, 6.57]
8.2 0.2 mg IV versus 0.5 mg IM	1	54	Risk Ratio (M‐H, Fixed, 95% CI)	1.08 [0.16, 7.10]
8.3 Any IV Vitamin K (0.2 mg) versus any IM Vitamin K (0.2 mg and 0.5 mg)	1	80	Risk Ratio (M‐H, Fixed, 95% CI)	1.04 [0.20, 5.31]
9 Sepsis	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
9.1 0.2 mg IV versus 0.2 mg IM	1	52	Risk Ratio (M‐H, Fixed, 95% CI)	1.0 [0.28, 3.58]
9.2 0.2 mg IV versus 0.5 mg IM	1	54	Risk Ratio (M‐H, Fixed, 95% CI)	0.86 [0.26, 2.86]
9.3 Any IV Vitamin K (0.2 mg) versus any IM Vitamin K (0.2 mg and 0.5 mg)	1	80	Risk Ratio (M‐H, Fixed, 95% CI)	0.92 [0.31, 2.72]
10 Mortality (all infants)	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
10.1 0.2 mg IV versus 0.2 mg IM	1	67	Risk Ratio (M‐H, Fixed, 95% CI)	1.32 [0.56, 3.14]
10.2 0.2 mg IV versus 0.5 mg IM	1	64	Risk Ratio (M‐H, Fixed, 95% CI)	2.82 [0.84, 9.46]
10.3 Any IV Vitamin K (0.2 mg) versus any IM Vitamin K (0.2 mg and 0.5 mg)	1	98	Risk Ratio (M‐H, Fixed, 95% CI)	1.77 [0.80, 3.93]