Comparison 1. Anti‐adhesion therapy versus placebo or no treatment (tx) following operative hysteroscopy.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Live birth	2	107	Odds Ratio (M‐H, Fixed, 95% CI)	0.94 [0.42, 2.12]
1.1 Device vs no tx	1	24	Odds Ratio (M‐H, Fixed, 95% CI)	1.0 [0.18, 5.46]
1.2 Hormonal tx vs placebo/no tx	1	83	Odds Ratio (M‐H, Fixed, 95% CI)	0.93 [0.37, 2.33]
2 Clinical pregnancy	2	107	Odds Ratio (M‐H, Fixed, 95% CI)	0.86 [0.37, 2.01]
2.1 Device vs no tx	1	24	Odds Ratio (M‐H, Fixed, 95% CI)	1.0 [0.06, 18.08]
2.2 Hormonal tx vs placebo	1	83	Odds Ratio (M‐H, Fixed, 95% CI)	0.85 [0.35, 2.06]
3 Miscarriage	2	54	Odds Ratio (M‐H, Fixed, 95% CI)	0.68 [0.18, 2.57]
3.1 Device vs no tx	1	22	Odds Ratio (M‐H, Fixed, 95% CI)	0.66 [0.11, 4.00]
3.2 Hormonal tx vs placebo	1	32	Odds Ratio (M‐H, Fixed, 95% CI)	0.72 [0.10, 5.01]
4 Presence of intrauterine adhesions at second‐look hysteroscopy	8	560	Odds Ratio (M‐H, Fixed, 95% CI)	0.35 [0.21, 0.60]
4.1 Device vs no tx	1	60	Odds Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
4.2 Device + hormonal tx vs placebo/no tx	1	11	Odds Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
4.3 Hormonal tx vs placebo	1	85	Odds Ratio (M‐H, Fixed, 95% CI)	0.14 [0.01, 2.72]
4.4 Gel vs no tx	5	404	Odds Ratio (M‐H, Fixed, 95% CI)	0.37 [0.21, 0.64]
5 Mean adhesion scores at second‐look hysteroscopy in women not treated for intrauterine adhesions	1	132	Mean Difference (IV, Fixed, 95% CI)	‐1.46 [‐1.64, ‐1.29]
5.1 Gel vs no tx	1	132	Mean Difference (IV, Fixed, 95% CI)	‐1.46 [‐1.64, ‐1.29]
6 Mean adhesion scores at second‐look hysteroscopy in women treated for intrauterine adhesions	1	84	Mean Difference (IV, Fixed, 95% CI)	‐3.3 [‐3.37, ‐3.23]
6.1 Gel vs no tx	1	84	Mean Difference (IV, Fixed, 95% CI)	‐3.3 [‐3.37, ‐3.23]
7 Mild adhesions at second‐look hysteroscopy	6	494	Odds Ratio (M‐H, Fixed, 95% CI)	1.33 [0.68, 2.61]
7.1 Hormonal tx vs placebo/no tx	1	90	Odds Ratio (M‐H, Fixed, 95% CI)	0.19 [0.01, 4.10]
7.2 Gel vs no tx	5	404	Odds Ratio (M‐H, Fixed, 95% CI)	1.56 [0.77, 3.18]
8 Moderate or severe adhesions at second‐look hysteroscopy	6	494	Odds Ratio (M‐H, Fixed, 95% CI)	0.08 [0.03, 0.24]
8.1 Hormonal tx vs placebo/no tx	1	90	Odds Ratio (M‐H, Fixed, 95% CI)	0.33 [0.01, 8.22]
8.2 Gel vs placebo/no tx	5	404	Odds Ratio (M‐H, Fixed, 95% CI)	0.07 [0.02, 0.23]