Comparison 4. Metformin and letrozole versus letrozole alone.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Live birth rate	1	134	Odds Ratio (M‐H, Fixed, 95% CI)	1.0 [0.48, 2.08]
2 Adverse events (gastrointestinal side effects)	1	134	Odds Ratio (M‐H, Fixed, 95% CI)	16.74 [0.94, 299.23]
3 Clinical pregnancy rate	1	134	Odds Ratio (M‐H, Fixed, 95% CI)	1.27 [0.64, 2.51]
4 Miscarriage rate per woman	1	134	Odds Ratio (M‐H, Fixed, 95% CI)	1.61 [0.61, 4.23]
5 Sensitivity analysis: miscarriage rate per pregnancy	1	62	Odds Ratio (M‐H, Fixed, 95% CI)	1.5 [0.51, 4.42]