***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 It is generally accepted that the age-related increased aneuploidy rate is correlated with reduced implantation and a higher abortion rate . Therefore , advanced maternal age ( AMA ) couples are a good target group to assess the possible benefit of preimplantation genetic diagnosis for aneuploidy screening ( PGD-AS ) on the outcome after assisted reproductive technology ( ART ) . METHODS A prospect i ve r and omized controlled clinical trial ( RCT ) was carried out comparing the outcome after blastocyst transfer combined with PGD-AS using fluorescence in situ hybridization ( FISH ) for the chromosomes X , Y , 13 , 16 , 18 , 21 and 22 in AMA couples ( aged > or = 37 years ) with a control group without PGD-AS .  From the 400 ( 200 for PGD-AS and 200 controls ) couples that were allocated to the trial , an oocyte pick-up was performed effectively in 289 cycles ( 148 PGD-AS cycles and 141 control cycles ) . RESULTS Positive serum HCG rates per transfer and per cycle were the same for PGD-AS and controls : 35.8 % ( 19.6 % ) [ % /per embryo transfer ( per cycle ) ] and 32.2 % ( 27.7 % ) , respectively ( NS ) . Significantly fewer embryos were transferred in the PGD-AS group than in the control group ( P<0.001 ) . The implantation rate ( with fetal heart beat ) was 17.1 % in the PGD-AS group versus 11.5 % in the control group ( not significant ; P=0.09 ) . We observed a normal diploid status in 36.8 % of the embryos . CONCLUSIONS This RCT provides no arguments in favour of PGD-AS for improving clinical outcome per initiated cycle in patients with AMA when there are no restrictions in the number of embryos to be transferred OBJECTIVE The purpose of this study was to determine the positive predictive value ( PPV ) and negative predictive value ( NPV ) of FISH analysis and to determine which chromosomal abnormalities are most frequently confirmed . DESIGN Prospect i ve observational . SETTING IVF laboratory . PATIENT(S ) Two hundred forty-one embryos were analyzed from 98 patients . INTERVENTION(S ) FISH re analysis . MAIN OUTCOME MEASURE(S ) Embryos that would have been discarded in patients undergoing preimplantation genetic diagnosis ( PGD ) were fixed and FISH re analysis  was performed . Results of re analysis were compared with the day 3 diagnosis while PPV and NPV were calculated . RESULT ( S ) Among the 241 embryos , 198 embryos were abnormal and 43 were normal by day 3 FISH analysis . The PPV was 83 % and the NPV was 81 % . PPV was also determined for specific categories of aneuploidy , and certain abnormalities such as monosomies , trisomies , tetrasomies , and polyploidies were frequently confirmed on re analysis ( PPV > 80 % ) , whereas Turner syndrome diagnosis was not ( PPV = 17 % ) . CONCLUSION ( S ) FISH analysis offers a PPV of 83 % and NPV of 81 % when evaluating a single blastomere in conjunction with PGD . FISH errors and mosaicism are primarily responsible for the errors associated with FISH analysis in PGD OBJECTIVE To verify whether advantages can derive from the implementation of preimplantation genetic diagnosis for aneuploidy in patients with a poor prognosis of full-term pregnancy , compared with conventional treatment procedures . DESIGN A r and omized , controlled study . SETTING Reproductive Medicine Unit of the Società Italiana Studi Medicina della Riproduzione , Bologna , Italy . PATIENT(S ) In a total of 262 stimulated cycles , women presented with the following poor-prognosis indications : maternal age of > or = 36 years ( n = 157 ) , > or =3 previous IVF failures ( n = 54 ) , and an altered karyotype ( n = 51 ) . After giving consent , 127 patients underwent preimplantation genetic diagnosis for aneuploidy , whereas 135 controls underwent assisted zona hatching . INTERVENTION(S ) Analysis of chromosomes XY , 13 , 14 , 15 , 16 , 18 , 21 , and 22 was carried out with the fluorescence in situ hybridization technique in a blastomere biopsied from day 3 embryos . Assisted zona hatching was performed on day 3 embryos from the control group . MAIN OUTCOME MEASURE(S ) Embryo morphology and chromosomal status , number of transferred embryos , clinical pregnancies , implantation rates , and abortions . RESULT ( S ) In the study group , 717 embryos were analyzed by fluorescence in situ hybridization , and 60 % were chromosomally abnormal . A mean of 2.3+/-0.9 euploid embryos were transferred in 99 cycles , result ing in 37 clinical pregnancies ( 37 % ) and a 22.5 % ongoing implantation rate . In the control group , 126 cycles were performed with 3.2+/-1.3 embryos transferred , yielding 34 clinical pregnancies ( 27 % ) and a 10.2 % ongoing implantation rate . CONCLUSION ( S ) The advantage of selecting embryos with a normal chromosome complement has an immediate impact on the ongoing implantation rate , especially in patients aged > or = 38 years and carriers of an altered karyotype OBJECTIVE To apply preimplantation genetic diagnosis ( PGD ) for the treatment of patients with a history of failed IVF-ET or habitual aborters . DESIGN Prospect i ve clinical study . SETTING Tertiary center for assisted reproduction . PATIENT(S ) Ninety-four couples with failed IVF-ET after > 2 IVF cycles and 64 couples with > 2 spontaneous abortions . INTERVENTION(S ) Patients were prepared for oocyte retrieval using st and ard controlled ovarian hyperstimulation protocol s after st and ard laboratory techniques . Blastomeres from 6- to 8-cell embryos were analysed using fluorescence in situ hybridization with commercial chromosomal probes , and normoploid embryos were transferred on day 3 after fertilization . MAIN OUTCOME MEASURE(S ) Pregnancy and implantation rates and live births . RESULT ( S ) Both 3- and 5-probe PGD result ed in a significantly higher outcome than controls for failed IVF-ET . Five-probe PGD appeared to be more suitable for habitual aborters . CONCLUSION ( S ) This pilot study suggests that 3-probe PGD is a valid option for failed IVF-ET patients . The use of five or more probes is indicated for habitual aborters BACKGROUND The use of ICSI has been a major breakthrough in the treatment of male infertility . Even azoospermic patients with focal spermatogenesis in the testis ( not sufficient to spill over into the ejaculate ) may benefit from the technique . Previous reports suggest a higher pregnancy rate after ICSI treatment in patients with obstructive azoospermia ( OA ) compared to their non-obstructive azoospermia ( NOA ) counterparts , which could be due to a higher aneuploidy frequency in the embryos of the latter group . We therefore conducted a prospect i ve cohort study to compare the aneuploidy frequency of the screened embryos between the two groups . METHODS From May 2001 until September 2003 , we offered couples with an OA or NOA partner ICSI in combination with preimplantation genetic diagnosis for aneuploidy screening . RESULTS No difference in age ( 30.6 and 33.5 years ) or stimulation parameters was observed between the two groups ; 53 and 60 % of the embryos were abnormal in the NOA and OA groups respectively ( P = not significant ) . CONCLUSIONS The aneuploidy frequency in embryos obtained from NOA as well as OA men is similar and very high , despite the young age of their female partners OBJECTIVE To determine aneuploidy for chromosome 16 by recycling nuclei of cells already analyzed for chromosomes X , Y , 18 , 13 , and 21 using multiple fluorescence in situ hybridization in preimplantation human embryos in a time frame compatible with clinical IVF and to asssess the incidence of chromosome 16 aneuploidy in embryos related to maternal age . DESIGN Prospect i ve experimental study . SETTING In vitro fertilization program in a tertiary center . PATIENTS One hundred four consenting patients undergoing IVF .  MAIN OUTCOME MEASURES Chromosome 16 ploidy was analyzed in a total of 195 embryos . In 89 embryos , a st and ard multiple-probe fluorescence in situ hybridization was used for chromosomes X , Y , 18 and 16 ( series 1 ) . The remaining 106 embryos ( series 2 ) were reanalyzed with a new procedure for chromosome 16 , which involves rehybridization with a digoxigenin-labeled alpha satellite probe after the st and ard analysis for chromosomes X , Y , 18 , 13 , and 21 was completed . The embryos were assigned to one of three groups according to the women 's age ; group 1 : < /= 34 years ( n = 34 ) , group 2 : 35 to 39 years ( n = 47 ) ; group 3 : > /= 40 years ( n = 23 ) . RESULTS Successful analysis , including biopsy , fixation , and fluorescence in situ hybridization was achieved in 86 % of the blastomeres within approximately 10 hours . A significant relationship was found between the rate of aneuploidy for chromosome 16 and increasing maternal age : group 1 : 0 % , group 2 : 6.3 % , and group 3 : 11.7 % . Monosomy for chromosome 16 was found in 72.7 % of the 11 embryos carrying chromosome 16 anomalies , with the remaining three embryos having two trisomies and one tetrasomy . This new protocol was applied clinical ly to five patients undergoing preimplantation aneuploidy assessment . Aneuploidy for chromosome 16 was found in five embryos from three of those patients . CONCLUSIONS This study demonstrates that preimplantation genetic diagnosis of the major human aneuploidies is achievable within a time frame compatible with IVF . In addition , this study confirms , for embryos , the existing data from spontaneous abortions suggesting that chromosome 16 aneuploidy increases with maternal age . The high prevalence of embryonic monosomy , which is rarely found in spontaneous abortions , suggests that monosomy 16 could be a factor associated with failure of implantation , as well as pointing to a different mechanism involved in the generation of chromosome 16 aneuploidy OBJECTIVE To verify the percentage of chromosomally abnormal preimplantation embryos in patients with a poor prognosis and possibly to increase the chance of implantation by selecting chromosomally normal embryos . DESIGN A prospect i ve , r and omized , controlled study . SETTING In vitro fertilization program at the Reproductive Medicine Unit of the Società Italiana Studi Medicina della Riproduzione , Bologna , Italy . PATIENT(S ) In a total of 28 stimulated cycles , the maternal age was > or = 38 years and /or the patient had > or = 3 previous IVF failures , factors that indicated a poor prognosis . After consent , 11 patients underwent preimplantation genetic diagnosis for aneuploidy , whereas 17 controls underwent assisted zona hatching .  INTERVENTION(S ) Simultaneous analysis of chromosomes X , Y , 13 , 18 , and 21 in a blastomere biopsied from day-3 embryos . Chromosomal analysis was performed with fluorescence in situ hybridization . Assisted zona hatching was performed on day-3 embryos from the control-group patients . MAIN OUTCOME MEASURE(S ) Embryo morphology , results of fluorescence in situ hybridization , clinical pregnancies , and implantation . RESULT ( S ) In the study group , a total of 61 embryos were analyzed by fluorescence in situ hybridization , and 55 % were chromosomally abnormal . Embryo transfer with at least one normal embryo was performed in 10 cycles . Four clinical pregnancies result ed , with a 28.0 % implantation rate . In the control group , 41 embryos were transferred in 17 cycles after the assisted zona hatching procedure , yielding four clinical pregnancies and an 11.9 % implantation rate . CONCLUSION ( S ) Infertile patients classified as having a poor prognosis have a high percentage of chromosomally abnormal embryos . The advantage of selecting and transferring embryos with normal fluorescence in situ hybridization results has an immediate impact on implantation OBJECTIVE To analyze the incidence of numeric chromosomal abnormalities in preimplantation embryos from women with unexplained recurrent miscarriage ( RM ) so as to seek an etiology and to determine whether the 
    Output:
    
To date there is insufficient data to determine whether PGS is an effective intervention in IVF/ICSI for improving live birth rates .
Available data on PGS for advanced maternal age showed no difference in live birth rate and ongoing pregnancy rate .