***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background : Implantation remains a limiting step in IVF/ICSI . Endometrial injury isa promising procedure aim ing at improving the implantation and pregnancy rates after IVF/ICSI . Objective : The aim of this study was to evaluate the effect of endometrial injury induced in precedingcycle on IVF/ICSI outcome . Material s and Methods : Four hundred patients undergoing their first IVF/ICSI cycle in two IVF units in Minia , Egypt were r and omly selected to undergo either endometrial injury in luteal phase of preceding cycle ( intervention group ) or no treatment ( control group ) . Primary outcome wasthe implantation and live birth ratesWhile the secondary outcome was clinical pregnancy , miscarriage , multiple pregnancy rates , pain and bleeding during and after procedure . Results : Implantation and live birth rates were significantly higher in intervention compared with control group ( 22.4 % vs. 18.7 % , p=0.02 and 67 % vs. 28 % , p=0.03 ) , respectively . There was also a significant reduction in miscarriage rate in intervention group ( 4.8 % vs. 19.7 % , respectively , p<0.001 ) . Conclusion : Endometrial injury in preceding cycle improves the implantation rate and live birth rate and reduces the miscarriage rate per clinical pregnancy in patients undergoing their first IVF/ICSI cycle Background Success rates of assisted reproductive techniques ( ART ) are approximately 30 % , with the most important limiting factor being embryo implantation . Mechanical endometrial injury , also called ‘ scratching ’ , has been proposed to positively affect the chance of implantation after embryo transfer , but the currently available evidence is not yet conclusive . The primary aim of this study is to determine the effect of endometrial scratching prior to a second fresh in vitro fertilization/intracytoplasmic sperm injection ( IVF/ICSI ) cycle on live birth rates in women with a failed first IVF/ICSI cycle . Method Multicenter r and omized controlled trial in Dutch academic and non-academic hospitals . A total of 900 women will be included of whom half will undergo an endometrial scratch in the luteal phase of the cycle prior to controlled ovarian hyperstimulation using an endometrial biopsy catheter . The primary endpoint is the live birth rate after the 2nd fresh IVF/ICSI cycle . Secondary endpoints are costs , cumulative live birth rate ( after the full 2nd IVF/ICSI cycle and over 12 months of follow-up ) ; clinical and ongoing pregnancy rate ; multiple pregnancy rate ; miscarriage rate and endometrial tissue parameters associated with implantation failure . Discussion Multiple studies have been performed to investigate the effect of endometrial scratching on live birth rates in women undergoing IVF/ICSI cycles . Due to heterogeneity in both the method and population being scratched , it remains unclear which group of women will benefit from the procedure . The SCRaTCH trial proposed here aims to investigate the effect of endometrial scratching  prior to controlled ovarian hyperstimulation in a large group of women undergoing a second IVF/ICSI cycle . Trial registration NTR 5342 , registered July 31st , 2015 . Protocol versionVersion 4.10 , January 4th , 2017 Background Mechanical endometrial injury prior to IVF has been suggested as a means to increase implantation rates by improving endometrial receptivity . However , the effects of endometrial injury in proliferative vs. luteal phase have not been studied before . This study aim ed to explore whether endometrial injury in the proliferative phase of the preceding cycle before in vitro fertilization/embryo transfer ( IVF-ET ) improves the clinical outcomes in unselected subfertile women compared with injury in luteal phase . Methods A group of 142 patients who were good responders to hormonal stimulation were r and omized into four groups : injury group ( group A : endometrial injury in proliferative phase , n = 38 ; group B : endometrium injury in luteal phase , n = 32 ) , and non-injury group as control ( group C : non-injury in proliferative phase , n = 36 ; group D : non-injury in luteal phase , n = 36 ) . Patients in injury groups underwent endometrial injury in either proliferative phase or luteal phase in the preceding cycle before IVF treatment . Clinical outcomes including implantation , pregnancy , and live birth rates were analyzed among the four groups . Results The baseline characteristics of the four groups including age , body mass index , duration , type and causes of infertility were similar . There were no significant differences in implantation , clinical pregnancy or live birth rates between injury group and non-injury group . Moreover , there were also no significant differences in implantation , clinical pregnancy , or live birth rates in injury in proliferative phase compared with luteal phase . Conclusions Endometrial injury in the cycle preceding IVF of unselected subfertile women does not increase implantation , clinical pregnancy , or live birth rates . Furthermore , there is no significant difference in clinical outcomes between endometrial injury in the proliferative phase and injury in the luteal phase . Trial registration This study was retrospectively registered on May 26th , 2017 ( ChiCTR-IOR-17011506 ) OBJECTIVE To evaluate the effectiveness of local endometrial injury in women undergoing in vitro fertilization ( IVF ) with at least one previous unsuccessful attempt . STUDY DESIGN R and omized controlled trial . Recruited women were r and omized into two groups . In group A ( pipelle group ) , women underwent pipelle biopsy twice in the luteal phase in the cycle prior to IVF . In group B ( control ) , women did not undergo any intervention prior to IVF . The primary outcome was clinical pregnancy rate . The secondary outcomes included live birth , miscarriage , multiple pregnancy and preterm delivery rates . RESULTS One hundred and eleven women were included in the study with 55 in the pipelle group and 56 in the control arm . The baseline clinical characteristics were similar in both groups . The clinical pregnancy rates were not significantly different between pipelle and control group ( 34.09 % vs. 27.65 % ; Odds ratio , OR 1.35 , 95 % confidence interval , CI 0.55 - 3.30 ) . The live birth ( 31.81 % vs. 25.53 % ; OR 1.36 , 95 % CI 0.55 - 3.39 ) , multiple pregnancy ( 33.33 % vs. 61.54 % ; OR 0.31 , 95 % CI 0.07 - 1.47 ) , miscarriage ( 6.66 % vs. 7.69 % ; OR 0.86 , 95 % CI 0.05 - 15.23 ) and preterm delivery rates ( 35.71 % vs. 66.66 % ; OR 0.28 , 95 % CI 0.05 - 1.4 ) were also not significantly different between the two groups . CONCLUSION Current study did not find any improvement in IVF success rates following endometrial injury in woman undergoing IVF after previous failed attempt BACKGROUND : Management of repeated implantation failure despite transfer of good- quality embryos still remains a dilemma for ART specialists . Scrapping of endometrium in the nontransfer cycle has been shown to improve the pregnancy rate in the subsequent IVF/ET cycle in recent studies . AIM : The objective of this r and omized controlled trial ( RCT ) was to determine whether endometrial injury caused by Pipelle sampling in the nontransfer cycle could improve the probability of pregnancy in the subsequent IVF cycle in patients who had previous failed IVF outcome . SETTING : Tertiary assisted conception center . DESIGN : R and omized controlled study . MATERIAL S AND METHODS : 100 eligible patients with previous failed IVF despite transfer of good- quality embryos were r and omly allocated to the intervention group and control groups . In the intervention group , Pipelle endometrial sampling was done twice : One in the follicular phase and again in the luteal phase in the cycle preceding the embryo transfer cycle . OUTCOME MEASURE : The primary outcome measure was live birth rate . The secondary outcome measures were implantation and clinical pregnancy rates . RESULTS : The live birth rate was significantly higher in the intervention group compared to control group ( 22.4 % and 9.8 % P = 0.04 ) . The clinical pregnancy rate in the intervention group was 32.7 % , while that in the control group was 13.7 % , which was also statistically significant ( P = 0.01 ) . The implantation rate was significantly higher in the intervention group as compared to controls ( 13.07 % vs 7.1 % P = 0.04 ) . CONCLUSIONS : Endometrial injury in nontransfer cycle improves the live birth rate , clinical pregnancy and implantation rates in the subsequent IVF-ET cycle in patients with previous unsuccessful IVF cycles Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more Aim : To evaluate the effect of local injury to the endometrium during spontaneous menstrual cycles before in vitro fertilization ( IVF ) treatment on implantation and pregnancy rates in women with recurrent implantation failure ( RIF ) . Methods : In a prospect i ve r and omized controlled trial ( RCT ) , a total of 36 patients , with RIF undergoing IVF  , were r and omized to two groups . In 18 patients , endometrial biopsies were performed using a pipelle curette on days 9–12 and 21–24 of the menstrual cycle preceding IVF treatment . In 18 control patients , a cervical pipelle was performed . Results : The implantation rate ( 2.08 % versus 11.11 % ; p = 0.1 ) , clinical ( 0 % versus 31.25 % ; p < 0.05 ) and live births rates ( 0 % versus 25 % ; p = 0.1 ) were lower in the experimental group compared with controls . Conclusion : Our RCT did not find any benefit from local injury to the endometrium in women with a high number of RIFs . Further studies are warranted to better define the target population of patients who may benefit from this procedure OBJECTIVE To study whether an injury-induced inflammation might be the mechanism underlying the favorable effect of endometrial biopsy on the implantation rate in in vitro fertilization ( IVF ) patients . DESIGN Controlled clinical study . SETTING A medical center IVF unit and a research institute . PATIENT(S ) Women undergoing IVF who had previous failed treatment cycles . INTERVENTION(S ) Endometrial sample s were collected from two groups of patients on day 21 of their spontaneous menstrual cycle . The experimental , but not the control group underwent prior biopsy treatment on days 8 or/ and 11 to 13 of that same cycle . MAIN OUTCOME MEASURE(S ) Abundance of immune cells , cytokines/chemokines level , correlation between these parameters and pregnancy outcome . RESULT ( S ) A statistically significantly higher amount of macrophages/dendritic cells ( HLA-DR+ CD11c+ cells ) and elevated proinflammatory cytokines , tumor necrosis factor-α ( TNF-α ) , growth-regulated oncogene-α ( GRO-α ) , interleukin-15 ( IL-15 ) , and macrophage inflammatory protein 1B ( MIP-1B ) , were detected in day-21 endometrial sample s of the experimental group . A direct stimulatory effect of TNF-α on MIP-1B , GRO-α , and IL-15 messenger RNA ( mRNA ) expression was demonstrated . A positive correlation was found between the levels of macrophages/dendritic cells , MIP-1B expression , and TNF-α expression and the pregnancy outcome . CONCLUSION ( S ) A biopsy-induced inflammatory response may facilitate the preparation of the endometrium for implantation . Increased MIP-1B expression could possibly serve for prediction of implantation competence Background : Though Assisted Reproductive Techniques have overcome many fertility disorders , implantation is still considered , the rate-limiting step for the success of IVF . Aim 0 : The aim of this study was to evaluate the role of endometrial scratching in improving the implantation rate in patients undergoing IVF-ET cycles . Design : Prospect i ve r and omized control trial . Methods and Material : Sixty infertile women with a history of > 1 previous failed IVF-ET cycles were r and omizedinto two groups of 30 each . The patients in group 1 underwent endometrial scratching once between days 14 - 21 of menstrual cycle in the cycle prior to embryo transfer ( ET ) , while in group 2scratching were not done . Implantation rate , ongoing pregnancy rate , abortion rate and live birth rate were comparedbetween both groups . Statistical Analysis : Mean values were compared between two groups using Student′s′t′ independent test . Frequency distributions of categorical variables were compared using Chi-Square/ Fisher′s exact test as appropriate . Results : Implantation rate in group 1 was 19.4 % whereas in group 2 it was 8.1 % . Difference between two groups was statistically significant ( P = 0.028 ) . The live birth rate was higher in the group 2 compared to group 1 , however this difference was not statistically significant ( 3.3 % vs 10 % , P = 0.612 ) . No significant difference was observed between the two groups regarding the ongoing pregnancy rate ( 16.7 % vs 0.0 % ; P = 0.052 ) , abortion rate ( 10.0 % vs 3.3 % , P =  
    Output:
    
SUMMARY ANSWER It remains unclear if endometrial scratching improves the chance of pregnancy and , if so , for whom .
Subgroup analysis of the overall groups showed no significant difference for miscarriage and multiple pregnancy rate .
WIDER IMPLICATION S OF THE FINDINGS It remains unclear if endometrial scratching improves the chance of pregnancy for women undergoing ART and , if so , for whom .