Comparison 1. Embryo culture supernatant vs no intervention.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1.1 live birth/ongoing pregnancy	3	340	Odds Ratio (M‐H, Fixed, 95% CI)	1.11 [0.73, 1.70]
1.1.1 Age ≤ 37	2	150	Odds Ratio (M‐H, Fixed, 95% CI)	1.36 [0.73, 2.54]
1.1.2 Age > 37	1	190	Odds Ratio (M‐H, Fixed, 95% CI)	0.94 [0.53, 1.68]
1.2 miscarriage	4	430	Odds Ratio (M‐H, Fixed, 95% CI)	0.89 [0.44, 1.78]
1.2.1 Age ≤ 37	3	240	Odds Ratio (M‐H, Fixed, 95% CI)	0.86 [0.40, 1.85]
1.2.2 Age > 37	1	190	Odds Ratio (M‐H, Fixed, 95% CI)	1.04 [0.21, 5.31]
1.3 clinical pregnancy	5	526	Odds Ratio (M‐H, Fixed, 95% CI)	1.13 [0.80, 1.61]
1.3.1 Age ≤ 37	4	336	Odds Ratio (M‐H, Fixed, 95% CI)	1.26 [0.81, 1.96]
1.3.2 Age > 37	1	190	Odds Ratio (M‐H, Fixed, 95% CI)	0.95 [0.54, 1.68]
1.4 ectopic pregnancy	2	250	Odds Ratio (M‐H, Fixed, 95% CI)	0.32 [0.01, 8.24]
1.5 multiple pregnancy	2	150	Odds Ratio (M‐H, Fixed, 95% CI)	0.70 [0.26, 1.83]
1.6 preterm delivery	1	90	Odds Ratio (M‐H, Fixed, 95% CI)	0.63 [0.17, 2.42]
1.7 foetal abnormalities	1	60	Odds Ratio (M‐H, Fixed, 95% CI)	3.10 [0.12, 79.23]