Table 2.

General features of studies included in the meta-analysis: 2. Treated uterine septum versus controls (untreated septum).

Study	Design	Period	Population	Exclusion Criteria	Sample Size; Case/Control	Outcomes	Cases	Controls	Follow-Up	Type of Hysetroscopy	Procedure/Metroplasty	Mode of Diagnosis	Method of Classification
Heinonen et al., 1997, [34]	Retrospective	1962–1995	Women who experienced recurrent abortions and/or infertility. Natural conception Recurrent miscarriage: one or more miscarriages	N/A	19/19	Pregnancy rate Spontaneous abortion Preterm labour Live birth rate	Women with uterine septum and subseptum who underwent hysteroscopic metroplasty. Septate uterus Subseptate uterus	Septate and subseptate with no treatment matched by age, gravidity and type of uterine anomaly.	Mean nine years (nine months—25 years)	26-gauge resectoscope (Karl Storz).	Jones procedure and Tompkins procedure respectively in six and 14 cases.	Not reported.	Buttram and Gibbons (1979) [25] criteria
Valli et al., 2004, [35]	Prospective	1990–2001.	Women who experienced recurrent abortions. Recurrent miscarriage: at least two miscarriages. Natural conception	Women with bicornuate uterus.	28/15	Pregnancy rate Spontaneous abortion Preterm labour Live birth rate	Women with uterine septum who underwent hysteroscopic metroplasty. Septate uterus	Untreated women.	36 months	Hamou hysteroscope (Karl Storz).	Resectoscope loop. Septum incision was performed until the underlying myometrial tissue.	HSC	AFS (1988) criteria [5]
Ban-Frangez et al., 2009, [29]	Retrospective	1993–2004.	Women with uterine septum that underwent IVF or ICSI and had a singleton pregnancy (fetal heart activity by ultrasound demonstration) Infertile: Tubal factor Endometriosis Endocrinologic Male factor Idiopathic ART conception: IVF or ICSI	Extrauterine pregnancies, multiple pregnancies and cases with an empty gestational sac.	106/212	Spontaneous abortion Preterm labour	Women who had conceived after IVF or ICSI. Septate uterus	Women without uterine anomalies with a singleton pregnancy after IVF or ICSI	-	N/A	N/A	2D TV-US HSC	AFS (1988) criteria [5]
Lin et al., 2009, [36]	Retrospective	1998–2007.	Complete septum (from fundus to vagina). Infertile: defined as unsuccessfully trying to conceive for at least 1 full year Recurrent miscarriage: at least two miscarriages. Natural conception	Other abnormalities than utero- cervico-vaginal septum.	21/15	Pregnancy rate Spontaneous abortion Preterm labour Live birth rate	Vaginal septum removal plus hysteroscopic resection of the uterus septum. Septate uterus	Women that remained untreated.	Mean 18 months (six months—nine years)	N/A	N/A	3D TV-US hysterosalpingography	N/A
Pang et al., 2011, [37]	Prospective	January 2006 to March 2011.	Women with subseptate uterus and who have experienced recurrent spontaneous abortions (two first- trimester abortions). Recurrent miscarriage: at least two first-trimester Natural conception	Only one spontaneous abortion.	46/32	Spontaneous abortion Preterm labour Live birth rate	Women with uterine subseptum and who have experienced recurrent spontaneous abortion. Subseptate uterus	Women with subseptate uterus and who have experienced recurrent spontaneous abortion not treated with hysteroscopic metroplasty.	15 months	N/A	N/A	3D TV-US	AFS (1988) criteria [5]
Tonguc et al., 2011, [19]	Retrospective	January 2006 to January 2009.	Patients with a uterine septum and otherwise unexplained infertility. Infertile Natural conception	Patients who had a history of tuberculosis or endometriosis, endocrinologic problem, abdominal surgery, husband with mild or severe oligospermia at the spermiogram.	102/25	Pregnancy rate Spontaneous abortion Preterm labour Live birth rate	Women with uterine septum who underwent hysteroscopic metroplasty. Septate uterus	Patients who rejected the surgery.	14 months	26-Fr rigid hysteroscope (Karl Storz).	Incision of the septa at the lower margin and continued upward with a horizontal section from one tubal ostium to the other.	N/A	AFS (1988) criteria [5]
Sugiura-Ogasawara et al., 2014, [38]	Prospective	January 2003 to June 2009.	Women with a history of two or more consecutive miscarriages or one stillbirth and septate uterus. Recurrent miscarriage: at least two consecutive miscarriages Natural conception	Patients with a bicornuate uterus.	109/15	Pregnancy rate Spontaneous abortion Preterm labour Live birth rate	Women with uterine septum who underwent hysteroscopic metroplasty. Septate uterus	Patients who rejected the surgery.	Present but Not specified	N/A	Transcervical resection (TCR) or a Jones modified metroplasty.	Hysterosalpingography and/or 2D transvaginal ultrasound were used as the initial screening. Laparoscopy/ laparotomy and/or MRI	AFS (1988) criteria [5]
Rikken et al., 2020, [39]	Retrospective	January 2000 to August 2018.	Women with a history of subfertility, pregnancy loss or preterm birth. Infertile: defined as the inability to conceive for a minimal period of one year of trying to conceive Recurrent miscarriage: two or more, not necessarily consecutive Natural conception	Women that do not have a wish to conceive at time of diagnosis.	151/106	Pregnancy rate Spontaneous abortion Preterm labour Live birth rate	Women with uterine septum who underwent hysteroscopic metroplasty. Septate uterus Subseptate uterus	Women who had expectant management.	Mean 46 months	73 procedures performed with a Versa point device. 32 with scissors. 12 with electro-surgery. 34 unknown.	Intrauterine septum was completely removed.	Hysterosalpingography, 3D TV-US MRI saline or gel infusion sonohysterography or hysteroscopy combined with laparoscopy.	AFS (1988)[5] and ASMR (2016) [6] criteria
Whelan et al., 2020, [40]	Prospective	July 2004 to May 2012	Women with recurrent early pregnancy loss, uterine septum diagnosed and one subsequent pregnancy. Recurrent miscarriage: two or more documented pregnancy losses before 10 weeks of gestation	N/A	21/11	Spontaneous abortion Preterm labour Live birth rate	Women with recurrent early pregnancy loss, uterine septum diagnosed and one subsequent pregnancy who underwent histeroscopic metroplasty. Septate uterus	Women with recurrent early pregnancy loss, uterine septum diagnosed and one subsequent pregnancy untreated.	N/A	N/A	N/A	HSC 3D TV-US	ASMR (2016) criteria [6]

HSC: Hysteroscopy; TV-US: transvaginal-ultrasound; MRI: magnetic resonance imaging.