***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: In previous studies , a new IVF method of intracytoplasmic morphologically selected sperm injection ( IMSI ) was introduced , based on motile sperm organellar morphology examination ( MSOME ) . It was concluded that microinjection of morphologically selected sperm cells with strictly normal nucleus , defined by MSOME , improves IVF-ICSI outcome . The aim of the present study was to confirm this conclusion in new , enlarged study groups . Comparison between 80 couples , who underwent an IVF-IMSI trial , with matched couples , who underwent a st and ard IVF-ICSI procedure , confirmed that pregnancy rate following IVF-IMSI was significantly higher , and abortion rate significantly lower than in the routine IVF-ICSI ( 60.0 versus 25.0 % , and 14 versus 40 % respectively , P < or= 0.05 ) . Another comparison was performed between matched IMSI groups , where embryos were obtained from microinjection by spermatozoa with a morphologically normal nucleus ( ' best ' group , n = 70 ) and a ' second best ' group was selected , where embryos were obtained from microinjection of spermatozoa with minimal morphological impairment , since no other sperm cells were available . It was confirmed that microinjection by ' second best ' spermatozoa result in significantly lower pregnancy and delivery rates and significantly higher abortion rates than microinjection with ' best ' spermatozoa ( 25.7 versus 58.2 % , P < or= 0.01 ; 17.1 versus 52.8 % , P < or= 0.01 , and 33.3 versus 9.7 % , P < or= 0.02 respectively ) . The present study has strengthened previous conclusions STUDY QUESTION Does high-magnification sperm selection influence  oocyte fertilization and further embryo development ? SUMMARY ANSWER The present study did not show a difference in oocyte fertilization rate , nor in embryo development between high-magnification intracytoplasmic morphologically selected sperm injection ( IMSI ) and conventional ICSI . WHAT IS KNOWN ALREADY The presence of nuclear vacuoles in sperm seems to influence embryo development and more specifically blastocyst formation . The use of high magnification for morphological sperm selection prior to ICSI has been associated with higher pregnancy rates and lower miscarriage rates . STUDY DESIGN , SIZE , DURATION A prospect i ve sibling-oocyte study was conducted , including 350 ICSI cycles to alleviate male infertility . Cycles were included from March 2010 to November 2011 . PARTICIPANTS / MATERIAL S , SETTING , METHODS On the day of treatment , a high-magnification sperm morphology was assessed on at least 200 spermatozoa . Primary endpoints were oocyte fertilization rate and embryo development . Because embryo transfers were not r and omized , the clinical outcome ( clinical pregnancy rate per transfer cycle ) was descriptive . However , the embryologist selecting the embryos for transfer was blinded for the sperm selection procedure . MAIN RESULTS AND THE ROLE OF CHANCE  IMSI morphology was assessed in 330 semen sample s , result ing in the following distribution : 18.1 ± 14.8 % Grade I , 15.2 ± 10.3 % Grade II , 12.3 ± 9.1 % Grade III and 54.4 ± 23.2 % Grade  IV . Oocyte fertilization rate was 79.1 and 77.3 % after IMSI and ICSI , respectively ( NS , paired t-test ) . Embryo development was similar in both treatment groups up to Day 5 of preimplantation development . Comparable numbers of IMSI-only ( n = 125 ) and ICSI-only ( n = 139 ) embryo transfers were performed . Clinical pregnancies with fetal heart beat were equally distributed over transfers with embryos from IMSI-only ( 34.4 % ) or ICSI-only treatment ( 36.7 % ) . LIMITATIONS , REASONS FOR CAUTION The clinical outcome remains descriptive . No firm conclusions could be drawn on cycle rank as a possible indication for IMSI . WIDER IMPLICATION S OF THE FINDINGS The prevalence of vacuoles in normal-shaped spermatozoa is as low as 27.5 % . A routine application of IMSI in unselected artificial reproductive technology patients can not be advocated . STUDY FUNDING /COMPETING INTEREST(S ) None BACKGROUND Our preceding studies have already demonstrated the advantage of intracytoplasmic morphologically selected sperm injection ( IMSI ) over the conventional IVF-ICSI procedure in terms of pregnancy rate . This study was undertaken to determine whether the increased pregnancy outcome was attributable to the preferred nuclear morphology of the selected spermatozoa , and not to the special sperm preparation technique modified by IMSI . METHODS Comparison between two matched IMSI groups , i.e. negative comprising 38 cycles , where no spermatozoa with intact nuclei were available for microinjection ; and positive , involving ovum microinjection by spermatozoa with strictly defined morphologically normal nuclei . RESULTS Implantation and pregnancy rates were significantly higher , and abortion rates significantly lower , in the positive group compared with the negative group ( 25.0+/-25.9 versus 5.9+/-12.9 % , F=15.8 , P < or = 0.01 ; 52.6 versus 18.4 % , chi2=9.7 , P < or = 0.01 ; and 10.0 versus 57.1 % , chi2=7.1 , P < or = 0.02 , respectively ) . CONCLUSIONS Implantation and pregnancy by ICSI is associated with morphological nuclear normalcy of sperm . Sperm with a morphologically abnormal nucleus usually have low fertility potential , but some with certain nuclear abnormalities may still be able to produce pregnancy following ICSI OBJECTIVE To examine the effect of sperm morphology on embryo development at the chromosomal level . DESIGN Prospect i ve study . SETTING Assisted fertilization center . PATIENT(S ) Couples who underwent IVF-PGS cycle , as a result of advanced maternal age , were r and omly allocated into two groups : intracytoplasmic sperm injection ( ICSI ; n = 60 ) or intracytoplasmic morphologically selected sperm injection ( IMSI ; n = 60 ) . INTERVENTION(S ) IVF in conjunction with preimplantation genetic screening ( PGS ) . MAIN OUTCOME MEASURE(S ) Sperm nuclear morphology at high-magnification  ICSI and incidence of aneuploidy in derived embryo . RESULT ( S ) There was a significantly increased incidence for sex chromosome aneuploidy in ICSI embryos when compared with IMSI embryos ( 23.5 % vs. 15.0 % , respectively ) . High-magnification sperm selection was associated with a significantly lower risk of sex chromosome abnormalities ( odds ratio [ OR ] , 0.57 ; confidence interval [ CI ] , 0.37 - 0.90 ) . The incidence of chaotic embryos was also significantly higher with the ICSI procedure ( 27.5 % vs. 18.8 % ) , while the IMSI procedure was associated with a significantly lower risk of chaotic embryos ( OR , 0.64 ; CI , 0.43 - 0.96 ) . Moreover , the cycle cancellation rate was significantly higher in ICSI cycles ( 11.8 % vs. 2.5 % ) . High-magnification sperm selection was a significant predictor of the likelihood of cycle cancellation ( OR , 0.26 ; CI , 0.11 - 0.62 ) . CONCLUSION ( S ) Spermatozoa free of nuclear morphological malformations were found to be significantly associated with the lower incidence of aneuploidy in derived embryos , result ing in lower rates of cycle cancellation OBJECTIVE To verify whether microinjection into retrieved oocytes of motile spermatozoa with morphologically normal nuclei , strictly defined by high power light microscopy ( x > 6000 ) , improves the IVF/intracytoplasmic sperm injection ( ICSI ) pregnancy rate in couples with repeated ICSI failures . DESIGN Comparative prospect i ve study testing routine IVF/ICSI outcome parameters against those of modified ICSI based on morphological selection of spermatozoa with normal nuclei . SETTING Male factor fertility laboratory and IVF center . PATIENT(S ) Sixty-two couples , with at least two previous consequent pregnancy failed ICSI cycles , underwent a single ICSI trial preceded by morphological selection of spermatozoa with normal nuclei . Fifty of these couples were matched with couples who underwent a routine ICSI procedure at the same IVF center and exhibited the same number of previous ICSI failures . INTERVENTION(S ) St and ard ICSI and modified ICSI . MAIN OUTCOME MEASURE(S ) ICSI pregnancy rate . RESULT ( S ) The matching study revealed that pregnancy rate after modified ICSI was significantly higher than that of the routine ICSI procedure ( 66.0 % vs. 30.0 % ) . CONCLUSION ( S ) Microinjection into retrieved oocytes of selected spermatozoa with strictly defined morphologically normal nuclei improves significantly the incidence of pregnancy in couples with previous ICSI failures Background The purpose of this study was to compare laboratory and clinical outcomes of intracytoplasmic morphologically selected sperm injection ( IMSI ) and conventional intracytoplasmic sperm injection ( ICSI ) in couples with repeated implantation failures . Methods A total of 200 couples with at least two prior unsuccessful ICSI cycles were enrolled : 100 couples were su bmi tted to IMSI and 100 were su bmi tted to routine ICSI . For IMSI , spermatozoa were selected at 8400 × magnification using an inverted microscope equipped with Nomarski ( differential interference contrast ) optics . For conventional ICSI , spermatozoa were selected at 400 × magnification . Clinical outcomes were evaluated between the two groups . Results Study patients were comparable in age , number of treatment failures , aetiology of infertility , percentage of normal form assessed by MSOME ( motile sperm organelle morphology examination ) , semen parameters , total number of oocytes collected , number of mature oocytes collected , total number of embryos transferred and number of high- quality embryos transferred . No statistically significant differences between the two groups were observed with regard to rates of fertilisation , implantation and pregnancy/cycle . Although not statistically significant , rates of miscarriage  ( IMSI:15.3 % vs ICSI:31.7 % ) , ongoing pregnancy ( IMSI:22 % vs ICSI:13 % ) and live births ( IMSI:21 % vs ICSI:12 % ) showed a trend towards better outcomes in the IMSI group . In addition , analysis of sub population s with or without male factor showed similar results . Conclusions Our results suggest that IMSI does not provide a significant improvement in clinical outcome compared to ICSI , at least in couples with repeated implantation failures after conventional ICSI . However , it should be noted that there were clear trends for lower miscarriage rates ( ≈50 % reduced ) and higher rates of ongoing pregnancy and live births ( both nearly doubled ) within the IMSI group . Further confirmation as well as r and omized large-scale trials are needed to confirm the beneficial effects of IMSI in couples with poor reproductive prognoses This prospect i ve r and omized study investigated whether intracytoplasmic sperm injection ( ICSI ) outcome can be improved with sperm pre selection under ×6000 magnification and intracytoplasmic morphologically selected sperm injection ( IMSI ) in patients with teratozoospermia and characterized embryo development and quality regarding sperm morphology and presence of head vacuoles . Couples with isolated teratozoospermia were divided into two groups : IMSI group ( n=52 ) and ICSI group ( n=70 ) and fertilization , blastocyst and clinical pregnancy rates were compared . Oocytes from 30 r and omly chosen patients from the IMSI group were injected with spermatozoa that had been previously classified under ×6000 magnification into four classes according to the number and size of vacuoles in the head and then cultured separately . Pronuclear morphology , embryo development and blastomere viability were estimated to investigate the influence of sperm morphology , especially vacuoles , on embryo developmental capacity . A significantly higher clinical pregnancy rate was achieved in the IMSI group compared with the ICSI group ( 48 % versus 24 % , P<0.05 ) . Fertilization with spermatozoa without head vacuoles yielded higher number of morphologically normal zygotes , higher blastocyst rate and smaller proportion of arrested embryos than spermatozoa with vacuoles and other head defects . IMSI is a method of choice in patients with teratozoospermia Background Sperm of poor quality can negatively affect embryo development to the blastocyst stage . The aim of this comparative prospect i ve r and omized study was to evaluate the role of an intracytoplasmic morphologically selected sperm injection ( IMSI ) in the same infertile couples included in the programme of intracytoplasmic sperm injection ( ICSI ) due to their indications of male infertility which had result ed in all arrested embryos following a prolonged 5-day culture in previous ICSI cycles . Methods Couples exhibiting poor semen quality and with all arrested embryos following a prolonged 5-day culture in previous ICSI cycles were divided into two groups : Group 1 : IMSI group ( n = 20 ) with IMSI performed in a current attempt and Group 
    Output:
    
None of the included studies reported congenital abnormalities .
AUTHORS ' CONCLUSIONS Results from RCTs do not support the clinical use of IMSI .
There is no evidence of effect on live birth or miscarriage and the evidence that IMSI improves clinical pregnancy is of very low quality .
There is no indication that IMSI increases congenital abnormalities .