1. Cycle characteristics of included trials.

Study ID	Population	Previous HSG or hysteroscopy	Intervention	Additional endometrial biopsy	Detected abnormalities treated	Timing of hysteroscopy
Seyam 2015	Unexplained infertility of 2 years duration	Normal HSG	Hysteroscopy	No	Yes	Follicular phase
Aghahosseini 2012	Two or more IVF failures	Normal HSG; no hysteroscopy in previous 2 months	Hysteroscopy	No	No details	No details available
Alleyassin 2017	First IVF	Normal HSG; women with history of hysteroscopy excluded.	Hysteroscopy	No	Yes	Preceding cycle; luteal phase
Demirol 2004	Two or more IVF failures	Normal HSG; no details of history of hysteroscopy	Hysteroscopy	No	Yes	Preceding cycle; follicular phase
El‐Nashar 2011	Unselected IVF population	No details of HSG; no details of history of hysteroscopy	Hysteroscopy	Yes	Yes	No details
Elsetohy 2015	First IVF	Normal HSG; no details of history of hysteroscopy	Hysteroscopy	No	Yes	Within 3 months of IVF; follicular phase
El‐Toukhy 2016	Two or more IVF failures	Hysteroscopy done within two months were excluded; Included women with previous history of hysteroscopy (45% in hysteroscopy group vs 44% in control)	Hysteroscopy	No	Yes; (only one partial septum not treated).	Preceding cycle; follicular phase
Juul Hare 2018	One IVF failure	No details available	Hysteroscopy	Yes	No details available	No details available
Rama Raju 2006	Two or more IVF failures	Normal HSG; no details of history of hysteroscopy	Hysteroscopy	Yes	Yes	Preceding cycle; follicular phase
Shawki 2012	Unselected IVF population	Normal HSG; no details of history of hysteroscopy	Hysteroscopy	Those with suspicious lesion after injecting methylene blue were biopsied.	Yes	No details available
Smit 2016	First IVF	Excluded those with previous hysteroscopy	Hysteroscopy	No	Yes; (31/43 abnormalities treated; 5 septum and 2 submucous fibroids not treated)	1 to 3 months before IVF; follicular phase

IVF: in vitro fertilisation

HSG: hysterosalpingography