Table 1 Methodological characteristics of eligible studies
Study, country of origin, number of centers, journal or meeting | Study period | Number of patients randomized | Randomization method | Allocation concealment | Blinding | Prospective power analysis performed | Primary outcome assessed | Financial Support | Protocol Registration | Authors contacted |
|---|---|---|---|---|---|---|---|---|---|---|
Karim Zadeh et al., (2008) [11], Iran, single center, Human Reproduction | Not reported | 160 (endometrial scratching: 80, control: 80) | Not reported | Not reported | Not reported | Not reported | Implantation (definition not reported) | Not reported | Not reported | Attempted; No response |
Karimzadeh et al., (2009) [12], Iran, single center, Australian and New Zealand Journal of Obstetrics and Gynaecology | Not reported | 115 (endometrial scratching: 58, control: 57) | Manual randomization (drawing a piece of paper from a bag) | Not reported | Not reported | Yes | Pregnancy (definition not reported) | Research and Clinical Center for Infertility, Shahid Sadoughi University of Medical Sciences | Not reported | Attempted; No response. |
Karimzade et al., (2010) [13], Iran, single center, Archives of Obstetrics and Gynaecology | 1 June,2008- 1 January, 2009 | 156 (endometrial scratching: 77, control: 79) | Computer generated randomization method | Not reported | Not reported | Not reported | Implantation (gestational sacs on U/S) | Not reported | Yes (retrospectively) | Attempted; No response |
Narvekar et al., (2010) [14], India, single center, Journal of Human Reproductive Sciences | May 2007- July 2008 | 100 (endometrial scratching: 49, control: 51) | Computer-generated random numbers | Third- party sealed consecutively numbered opaque envelopes | Non-blind | Not reported | Live birth (definition not reported) | Not reported | Not reported | Attempted; No response |
Safdarian et al., (2011) [15], Iran, single center, Iranian Journal of Reproductive Medicine | July 2008- March 2009 | 100 (endometrial scratching: 50, control: 50) | Computerized randomization | Not reported | Not reported | Not reported | Implantation (definition not reported) | Infertility Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran | Yes (retrospectively) | Attempted; No response |
Baum et al., (2012) [16], Israel, single center, Gynecological Endocrinology | July 2006- June 2009 | 36 (endometrial scratching: 18, control: 18) | Table of random numbers | Not reported | Single-blind (patients did not know in which group they were) | Not reported | Implantation (definition not reported) Clinical pregnancy (intrauterine gestational sac with embryonic pole on U/S) | Not reported | Not reported | Attempted; No response |
Inal et al., (2012) [17], Turkey, single center, European Journal of General Medicine | January 2008- March 2009 | 100 (endometrial scratching: 50, control: 50) | Computer-generated random numbers | Not reported | Not reported | Not reported | Live birth (Definition not reported) | None | Not reported | Attempted; No response |
Shohayeb et al., (2012) [18], Egypt and Saudi Arabia, double center, European Journal of Obstetrics & Gynecology and Reproductive Biology | Not reported | 210 (endometrial scratching: 105, control: 105) | Random number tables | Third- party closed sealed envelopes | Not reported | Not reported | Implantation (attachment of the embryo to the endometrium during a specific period which is called the window of implantation) Clinical pregnancy (gestational sac with embryonic cardiac activity) Abortion (definition not reported) Live birth (definition not reported) | Not reported | Not reported | Attempted; No response |
Nastri et al., (2013) [19], Brazil, single center, Ultrasound Obstetrics Gynecology | June 2010- March 2012 | 158 (endometrial scratching: 79, control: 79) | Computer generated random sequence of numbers in blocks of 30 (each block having 15 numbers assigned to intervention and 15 to control) | Third- party sealed consecutively numbered opaque envelopes Assigned as the participant entered the study; opened just before the procedure | Double-blind | Yes | Clinical pregnancy (at least one fetus with cardiac activity per allocated woman) | Brazilian official government research foundations: CNPq and CAPES | Yes | Attempted; No response |
Guven et al., (2014) [20], Turkey, single center, European Journal of obstetrics and gynecology and reproductive biology | September 2010- April 2011 | 124 (endometrial scratching: 62, control: 62) | Not reported | Sealed envelopes | Not reported | Not reported | Clinical pregnancy (intrauterine gestational sac with embryonic cardiac activity on TVS, 4 weeks after ET) | Not reported | Not reported | Attempted; No response |
Yeung et al., (2014) [21], Hong Kong, single center, Human Reproduction | March 2011- August 2013 | 300 (endometrial scratching: 150, control: 150) | Randomization in a 1: 1 ratio according to a computer-generated randomization list with blocks of 10 in sealed envelopes | Third- party sealed envelopes | Non-blind | Yes | Ongoing pregnancy (at least one sac with embryonic cardiac activity on U/S beyond 20 weeks of gestation) | Small Project Funding of the Committee on Research and Conference Grants, University of Hong Kong | Yes | No |
Gibreel et al., (2015) [22], Egypt, multicenter, Gynecology Endocrinology | Not reported | 387 (endometrial scratching: 193, control: 194) | Computer-generated tables of random numbers | Opaque sealed envelopes (on the day of start of pituitary downregulation) | Single-blind (patients did not know in which group they were) | Yes | Live birth (delivery of one or more living fetuses after 24 weeks of gestation) | Not reported | Yes | Attempted; No response. |
Singh et al., (2015) [23], India single center, Journal of Human Reproductive Sciences | April 2013- July 2014 | 60 (endometrial scratching: 30, control: 30) | Random allocation software | Not reported | Non-blind | Not reported | Implantation (gestational sac on TVS) | None | Not reported | Attempted; No response |
Xu et al., (2015) [24], China, single center, Reproductive BioMedicine Online | July 2012- July 2013 | 79 (endometrial scratching+G-CSF: 13, G-CSF: 14, control: 52) | Randomized number table | Not reported | Not reported | Not reported | Endometrial thickness Clinical pregnancy (gestational sac containing yolk sac at TVS, including ectopic pregnancy) Live birth (definition not reported) Implantation (gestational sac on TVS 4 weeks after ET) | Not reported | Not reported | Attempted; No response |
Zhang et al., (2015) [25], China, double center, Chinese Journal of Integrative Medicine | August 2009- March 2012 | 168 (endometrial scratching: 55, Chinese medicine: 56, control: 57) | Randomization with computer-generated list (concealed to the physician but not to the study nurse) | Not reported | Not reported | Not reported | Biochemical pregnancy (positive serum β-hCG level on day 14 after FET) Clinical pregnancy (intrauterine gestational sac with a cardiac activity 3 weeks after a positive β-hCG test) | Shanghai Municipal Health Bureau Foundation of Chinese Traditional Medicine | Not reported | Attempted; No response |
Aflatoonian et al., (2016) [26], Iran, single center, International Journal of Reproductive Biomedicine | March 2015- January 2016 | 100 (endometrial scratching: 50, control: 50) | Computer-generated randomization table | Not reported | Non-blind | Yes | Implantation (gestational sacs on TVS) Clinical pregnancy (gestational sac and embryonic cardiac activity on TVS 5 weeks after ET) | Research and Clinical Center for Infertility, Shahid Sadoughi University of Medical Sciences, Yazd, Iran | Yes (retrospectively) | Attempted; No response |
Shahrokh-Tehraninejad et al., (2016) [27], Iran, single center, Journal of Family and Reproductive Health | January 2013- December 2014 | 120 (endometrial scratching: 60, control: 60) | Manual randomization (drawing a piece of printed paper from a plastic bag) | Not reported | Not reported | Not reported | Clinical pregnancy (intrauterine gestational sac on TVS during week 5 after FET) | Not reported | Yes (retrospectively) | Attempted; No response |
Zygula et al., (2016) [28], Poland, European Journal of Obstetrics & Gynecology and Reproductive Biology | Not reported | 120 (endometrial scratching: 59, control: 61) | Not reported | Not reported | Not reported | Not reported | Clinical pregnancy (definition not reported) | Not reported | Not reported | Attempted; No response |
Liu et al., (2017) [29], China, single center, Reproductive Biology Endocrinology | February 2012- November 2014 | 142 (endometrial injury in proliferative phase: 38, endometrial injury in luteal phase: 32, control in proliferative phase: 36, control in luteal phase: 36) | Table of random numbers | Not reported | Single-blind (patients did not know in which group they were) | Not reported | Implantation (intrauterine gestational sac on U/S) | National Natural Science Foundation of China, Beijing Natural Science Foundation Project and Project Training High-Level Medical Technical Personnel in the Health System in Beijing | Yes (retrospectively) | Attempted; No response |
Mak et al., (2017) [30], Hong Kong, single center, Reproductive Biomedicine Online | March 2013- April 2016 | 229 (endometrial scratching: 115, control: 114) | Computer-generated random numbers | Third party opaque sealed envelopes | Double-blind | Yes | Pregnancy (Positive urine pregnancy test) | Not reported | Yes | No |
Tk et al., (2017) [31], India, single center, European Journal of Obstetrics, Gynecology and Reproductive Biology | April 2008- April 2015 | 111 (endometrial scratching: 55, control: 56) | Computer generated sequence generated in blocks of 10 | Consecutively numbered sealed opaque envelopes | Non-blind | Yes | Clinical pregnancy (gestational sac on U/S) | None | Yes (retrospectively) | Attempted; No response |
Maged et al., (2018) [32], Egypt, single center, International Journal of Gynecology and Obstetrics | January 1, 2016- March 31, 2017 | 300 (endometrial scratching: 150, control: 150) | Automated web-based randomization system | Sealed envelopes | Non-blind | Yes | Clinical pregnancy (embryonic cardiac activity within a gestational sac on U/S 4 weeks after ET) Implantation (gestational sacs on U/S 14 days after ET) | Not reported | Not reported | Yes |
Pecorino et al., (2018) [33], Italy, single center, Italian Journal of Gynaecology and Obstetrics | Not reported | 80 (endometrial scratching: 40, control: 40) | Not reported | Not reported | Non-blind | Not reported | Clinical pregnancy (intrauterine sac with embryonic cardiac activity on U/S) Implantation (definition not reported) | Not reported | Not reported | Attempted; No response |
Sherif et al., (2018) [34], Egypt, single center, Middle East Fertility Society Journal | Not reported | 60 (endometrial scratching: 30, control: 30) | Computer-generated randomization table (Research Randomizer Version 4.0 software) in a 1: 1 ratio | Not reported | Not reported | Yes | Pregnancy (definition not reported) | Not reported | Yes | Attempted; No response |
Eskew et al., (2019) [35], USA, single center, Journal of Assisted Reproduction and Genetics | September 2013- July 2017 | 100 (endometrial scratching: 53, control: 47) | Computer-generated block randomization | Consecutively numbered sealed opaque envelopes | Double-blind | Yes | Clinical pregnancy Live birth Miscarriage (definitions not reported) | 5T32HD055172-09 and UL1 TR002345 | Not reported | Attempted; No response |
Frantz et al., (2019) [36], France, multicenter, Human Reproduction | February 2010- July 2014 | 191 (endometrial scratching: 98, control: 93) | Randomization sequence was generated using SAS Software and was stratified by center with a 1: 1 allocation using random block sizes of 4 and 6 | Allocation using random block sizes of 4 and 6 | Non-blind | Yes | Clinical pregnancy (at least one intrauterine gestational sac with embryonic cardiac activity) | Ministère de la Santé Français | Yes | Yes |
Gurgan et al., (2019) [37], Tuukey, single center, Reproductive Biomedicine Online | February 2015- October 2017 | 305 (endometrial scratching: 153, control: 152) | Computer-generated random number sequence (1: 1 simple randomization) | Not reported | Not reported | No | Clinical pregnancy (at least one gestational sac with embryonic cardiac activity on U/S) Live birth (definition not reported) Implantation (gestational sacs on U/S) | Not reported | Yes, retrospectively | Attempted; No response |
Hilton et al., (2019) [38], Canada, multicenter, Archives of Gynecology and Obstetrics | May 2013- May 2015 | 51 (endometrial scratching: 25, control: 26) | SAS System for Windows- generated numbers accessed electronically (1: 1 ration, stratification by the study center) | Web-based randomization system | Non-blind | Yes | Clinical pregnancy (documented embryonic cardiac activity 5 weeks after implantation) | Ferring Inc.,Canada | Yes | Yes |
Lensen et al., (2019) [5, 6], (New Zeeland, UK, Belgium, Sweden), multicenter, New England Journal of Medicine | June 2014- June 2017 | 1364 (endometrial scratching: 690, control: 674) | Block randomization of two different sizes between 6 and 16 repeating in random order (1: 1 ratio, stratification according to recruiting site and to whether a fresh-ET or frozen-ET) | Block randomization of two different sizes between 6 and 16 repeating in random order | Non-blind | Yes | Live birth (Definition not reported) | University of Auckland and others | Yes | Attempted; No response |
Olesen et al., (2019) [39], Denmark, multicenter, Fertility Sterility | February 2014- December 2017 | 304 (endometrial scratching: 151, control: 153) | Randomization into blocks of 10 for each participating clinic (1: 1 ratio, according to an Internet-based randomization list) | Consecutively numbered opaque sealed envelopes | Non-blind | Yes | Clinical pregnancy (Definition not reported) | Health Research Fund of the Central Denmark | Yes | Attempted; No response |
Berntsen et al., (2020) [40], Denmark, double center, European Journal of Obstetrics and Gynecology and Reproductive Biology | 2013- 2018 | 229 (endometrial scratching: 122, control: 107) | Third-party computer randomization (simple 1: 1 randomization, without using block randomization or stratification) | Not reported | Non-blind | Yes | Positive pregnancy test (serum β-hCG>10 IU/l on day 13–15 after ET) | Department of Gynaecology and Obstetrics at Copenhagen University Hospital Hvidovre | Yes | Attempted; No response |
Izquierdo Rodriguez et al., (2020) [41], Spain, single center, Reproductive Sciences | January 2017-October 2018 (follow-up until October 2019) | 352 (endometrial scratching: 176, control: 176) | Simple randomization by web-based program | Not reported | Non-blind | Yes | Clinical pregnancy per ET (intrauterine gestational sac on TVS at approximately 6 weeks of gestation) | ProcreaTec Fertility Center | Yes | Attempted; No response |
Mackens et al. (2020) [42], Belgium, single center, Human Reproduction | 3 April 2014- 8 October 2017 | 200 (endometrial scratching:100, control:100) | Computer-generated randomization list | Sequentially numbered opaque sealed envelopes | Not reported | Yes | Clinical pregnancy (gestational sac on TVS at 7 weeks of gestation) | Fonds Wetenschappelijk Onderzoek’ (FWO, Flanders, Belgium) | Yes | Yes |
Tang et al., (2020) [43], China, single center, Journal of Obstetrics and Gynaecology Research | October 2017- February 2018 | 220 (endometrial scratching: 110, control: 110) | Manual randomization (sealed envelopes) (details on how the randomization list was generated were not provided) | Sealed envelopes | Non-blind | Yes | Clinical pregnancy (gestational sac on TVS approximately 5 weeks after ET) Live birth (deliveries that resulted in a live born after ET) Implantation (gestational sacs on TVS) | Funded by HeFei Municipal Health Planning Commission, Key Research and Development Project of AnHui Province, Key Talents of Maternal and Child Health in Jiangsu Province and Science Technology Innovation Project of Suzhou | Yes | No |
Van Hoogenhuijze et al., (2020) [8, 9], Netherlands, multicenter, Human reproduction | January 2016- July 2018 | 946 (endometrial scratching: 472, control :474) | Randomization 1: 1 centrally located, non-center-stratified by a web-based programme (ALEA Clinical B.V.) using randomly permuted blocks with block size varying randomly between two and four | Randomly permuted blocks with block size varying randomly between two and four | Non-blind | Yes | Live birth (delivery of at least one live fetus after 24 weeks of gestation) | Dutch organisation for funding of healthcare research ZonMW. The sponsor of the SCRaTCH study was the University Medical Centre Utrecht (UMCU) | Yes | Yes |
Metwally et al., (2021) [44], UK, multicenter, Human Reproduction | 4th July,2016- 24th October 2018 (follow-up until 24th October, 2019) | 1048 (endometrial scratching: 523, control: 525 | Randomization sequence generated by the trial statistician using a computer via a web-based system. 1: 1 stratified block randomization was used, with randomly permuted masked blocks of sizes 2, 4, and 6 stratified by site and planned IVF/ICSI (antagonist or long) | Web-based randomization system with restricted access rights that concealed allocation | Non-blind | Yes | Live birth (live birth beyond the 24th week of pregnancy) | National Institute for Health Research | Yes | No |
Zahiri et al., (2021) [45], Iran, single center, Galen Medical Journal | Not reported | 228 (endometrial scratching: 114, control: 114) | Not reported | Not reported | Not reported | No | Fetal heart activity (assessed via U/S) Multiple pregnancies (assessed via U/S) Abortion (loss of gestational products before the 12th week of gestation) | Vice-Chancellorship of Research and Technology, Guilan University of Medical Sciences | Yes | Attempted; No response |
Izquierdo et al., (2022) [46], Spain, single center, Journal of Gynecology Obstetrics and Human Reproduction | January 2017- October 2018 (follow-up until October 2019) | 352 (endometrial scratching: 176, control: 176) | Simple randomization by web-based program | Not reported | Non-blind | Yes | Live birth (birth of a living baby beyond the 24th week of pregnancy) | ProcreaTec Fertility Center; Analysis of cumulative Live birth rates did not receive specific funding | Yes | Attempted; No response |
Noori et al., (2022) [47], Iran, single center, Journal of Obstetrics and Gynaecology | May 2019- December 2019 | 100 (endometrial scratching: 50, control: 50) | Sealed envelopes were used as the means of randomization for allocating them into the study groups (details on how the randomization list was generated were not provided) | Sealed envelopes | Not reported | Yes | Chemical pregnancy (β-hCG positive test) Clinical pregnancy (at least 1 intrauterine gestational sac with embryonic cardiac activity) | Research Department of Zahedan University of Medical Sciences | Yes (retrospectively) | Attempted; No response |
Turktekin et al., (2022) [48], Turkey, single center, Annals of Clinical and Analytical Medicine | 2019-2020 | 60 (endometrial scratching: 30, control: 30) | Not reported | Not reported | Not reported | Not reported | Clinical pregnancy rate (evidence of a gestational sac, confirmed by U/S at the 4th week of transfer) Live birth (delivery of a live fetus after 24 completed weeks of gestational age) Serum β-hCG levels (measured in all patients on the 12th day of embryo transfer) Miscarriage (loss of fetus before 20 weeks of gestation) | None | Not reported | Attempted; No response |