***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: OBJECTIVE To assess the ability of a GnRH antagonist ( Cetrorelix , Asta Medica AG , Frankfurt , Germany ) to prevent premature LH surges in an IVF-ET program using a simple protocol with one or two administrations . DESIGN Controlled ovarian hyperstimulation was carried out in 17 women with three ampules a day of hMG , starting on day 2 of the menstrual cycle . A dose of 5 mg of Cetrorelix was administered when plasma E2 levels were between 150 and 200 pg/mL ( conversion factor to Sl unit , 3.671 ) per follicle of > or = 14 mm . A second injection was performed 48 hours later if the triggering of ovulation was not decided in the meantime . RESULTS Six patients received one injection and 11 patients received two administrations . Plasma LH levels showed a marked decrease and remained low after the administration of the GnRH antagonist . In six patients , the first administration of Cetrorelix was performed when a significant rise in LH plasma level was present . Even in these patients the GnRH antagonist was able to prevent an LH surge . The tolerance of the product was good . Six clinical pregnancies were obtained , of which four are ongoing ( 25 % per ET ) . Two ongoing pregnancies were obtained after the transfer of a frozen-thawed embryo ( 35.3 % per retrieval ) . CONCLUSIONS The GnRH antagonist Cetrorelix in a simple , unique or dual administration , protocol was able to prevent premature LH surge in all of the 17 patients studied . If these results are confirmed by larger , r and omized studies , the good tolerance and efficacy that we observed suggest a bright future for this product is assisted reproductive technologies New gonadotrophin-releasing hormone ( GnRH ) antagonists , which allow suppression of luteinizing hormone ( LH ) surges , have recently become available . We compared in this study the results of a single administration of 3 versus 2 mg Cetrorelix in 65 patients undergoing ovarian stimulation and in-vitro fertilization ( IVF ) . The GnRH antagonist ( Cetrorelix ) was non-r and omly administered at a dose of 3 mg ( 34 patients ) or 2 mg ( 32 patients ) on day 8 of the stimulation cycle . In the case of slow follicular development , the injection was delayed until oestradiol reached 400 pg/ml . No difference was observed in the decrease in LH and in oestradiol secretion between the 3 and the 2 mg groups , but the LH secretion was suppressed for a shorter time in the 2 mg group . No LH surge was observed in the 3 mg group , while one surge ( 3 % ) and one significant rise in LH were observed in the 2 mg group . No significant difference was observed in IVF results in the two groups of patients . This study demonstrates that a single injection of 3 or 2 mg successfully prevents LH surges for at least 3 days in all the patients treated . The LH rises in the 2 mg group led us to choose the 3 mg dose as a safer dose in our single administration protocol OBJECTIVE To confirm the value of a single dose of 3 mg of cetrorelix in preventing the occurrence of premature LH surges . DESIGN Multicenter r and omized , prospect i ve study . SETTING Reproductive medicine units . PATIENT(S ) Infertile patients undergoing ovarian stimulation for IVF-ET . INTERVENTION(S ) A single dose of 3 mg of cetrorelix ( Cetrotide ; ASTA Medica , Frankfurt , Germany ) ( 115 patients ) was administered in the late follicular phase . A depot preparation of triptorelin ( Decapeptyl ; Ipsen-Biotech , Paris , France ) was chosen as a control agent ( 39 patients ) . Ovarian stimulation was conducted with hMG ( Menogon ; Ferring , Kiel , Germany ) . MAIN OUTCOME MEASURE(S ) Premature LH surges ( LH level > 10 IU/L ) , progesterone level greater than 1 ng/L , and IVF results . RESULT ( S ) No LH surge occurred after cetrorelix administration . The patients in the  cetrorelix group had a lower number of oocytes and embryos . The percentage of mature oocytes and fertilization rates were similar in both groups , and the pregnancy rates were not statistically different . The length of stimulation , number of hMG ampules administered , and occurrence of the ovarian hyperstimulation syndrome were lower in the cetrorelix group . Tolerance of cetrorelix was excellent . CONCLUSION ( S ) A cetrorelix single-dose protocol prevented LH surges in all patients studied . It compares favorably to the " long protocol " and could be a protocol of choice in IVF-ET Abstract A prospect i ve , r and omized study was performed to compare the efficiency of hormonal stimulation for IVF ( in vitro fertilization ) in either the long luteal protocol , using the LHRH agonist Buserelin , or the multiple dose LHRH antagonist protocol , using the LHRH antagonist Cetrorelix . Here we present the data on the incidence of ovarian hyperstimulation syndromes ( OHSS ) . 85 and 188 patients were recruited for the stimulation in the LHRH agonist and in the LHRH antagonist protocol , respectively . The groups were comparable regarding anamnestic data . The incidence of WHO ° II and ° III OHSS was significantly lower in the Cetrorelix than in the Buserelin group ( 1.1 % vs. 6.5 % , p=0.03 ) . Additionally 3 patients in the Cetrorelix group ( 1.6 % ) and 5 patients in the Buserelin group ( 5.9 % ) did not receive hCG because of a threatening OHSS . The follicle maturation was more homogeneous in the Cetrorelix protocol , with less small follicles on the day of hCG administration but a similar number of oocyte cumulus complexes retrieved . The pregnancy rates per cycle were not significantly different in the Cetrorelix and Buserelin protocol ( 22 % vs. 26 % ) . The Cetrorelix multiple dose protocol is advantageous compared to the long protocol regarding the incidence of OHSS , a potentially life threatening complication of controlled ovarian stimulation This prospect i ve r and omized study compared the effectiveness of a flexible single-dose gonadotrophin-releasing hormone ( GnRH ) antagonist ( cetrorelix ) and a single-dose long GnRH agonist ( goserelin ) protocol for ovarian stimulation in IVF/intracytoplasmic sperm injection ( ICSI ) cycles . All patients from the waiting list were successively included in the study , pre-programmed with an oral contraceptive , and r and omized into goserelin and cetrorelix groups . Depending on the date on which their menstrual period started , patients took oral contraceptives for one or two cycles . Ultimately , 236 patients in the first group received a single dose of depot preparation of goserelin and 224 patients received a single 3 mg dose of cetrorelix in the late follicular phase , when the mean follicle diameter exceeded 12 mm . The mean number of ampoules of FSH and the duration of stimulation was statistically significantly lower in the cetrorelix group than in the goserelin group ( 25.9 versus 34.5 , and 9.6 versus 12.2 days , P < 0.01 ) . The mean number of oocytes retrieved was similar ( 6.7 + /- 4.5 versus 7.2 + /- 4.6 , NS ) . Similar results were observed in fertilization rates , blastulation rates and blastocyst transfer rates in both groups . Clinical pregnancy and delivery rates per cycle were higher in the goserelin group ( 34.3 and 30.1 % ) than in the cetrorelix group ( 31.9 and 28.3 % ) , but the differences were not statistically significant . The flexible single-dose GnRH antagonist protocol is an advantageous alternative to the long GnRH agonist protocol , with similar efficacy , shorter duration , a significant reduction in the number of FSH ampoules used and without the menopause-like effects of the GnRH antagonist In this prospect i ve and r and omized study , 188 patients received the luteinizing hormone-releasing hormone ( LHRH ) antagonist cetrorelix , and 85 patients the LHRH agonist buserelin  to prevent endogenous luteinizing hormone ( LH ) surges during ovarian stimulation in in-vitro fertilization (IVF)/intracytoplasmic sperm injection ( ICSI ) cycles . Ultimately , 181 patients ( 96.3 % ) in the  cetrorelix  group , and 77 ( 90.6 % ) in the buserelin group , reached the day of the human chorionic gonadotrophin ( HCG ) injection . The mean number of human menopausal gonadotrophin ( HMG ) ampoules administered and the mean number of stimulation days with HMG were significantly less in the cetrorelix group than in the buserelin group ( P < 0.01 ) . A rise in LH and progesterone concentrations was observed in three of the 188 patients ( 1.6 % ) who received cetrorelix . On the day of the HCG administration , more follicles of a small diameter ( 11 - 14 mm ) were observed in the buserelin group than in the cetrorelix group ( P = 0 . 02 ) and the mean serum oestradiol concentration was significantly higher in patients who received buserelin than in those who received cetrorelix ( P < 0.01 ) . Similar results were observed in fertilization , cleavage and pregnancy rates in the two groups . In conclusion , the use of the LHRH antagonists might be considered more advantageous because of the short-term application needed to inhibit gonadotrophin secretion , so allowing a reduction in the treatment time in a clinical ly significant manner Extending the FSH window for multifollicular development by administering FSH from the midfollicular phase onward constitutes a novel mild protocol for ovarian stimulation for in vitro fertilization ( IVF ) based on the physiology of single dominant follicle selection in normo-ovulatory women . We compared outcomes from this protocol with two other stimulation protocol s. One hundred and forty-two normo-ovulatory patients with an indication for IVF ( or IVF/ICSI ) were r and omized to a GnRH agonist long protocol ( group A ; n = 45 ) or one of two GnRH antagonist protocol s commencing recombinant FSH on cycle d 2 ( group B ; n = 48 ) or cycle d 5 ( group C ; n = 49 ) . A fixed dose ( 150 IU/d ) of rFSH was used for ovarian stimulation , and GnRH antagonist cotreatment was initiated on the day when the leading follicle reached 14 mm diameter . Group C showed a shorter duration of stimulation ( median duration , 11 , 9 , and 8 d for groups A , B , and C , respectively ; P < 0.001 ) , reflected in a significantly lower total dose of rFSH used ( median amount of rFSH , 1650 , 1350 , and 1200 IU for groups A , B , and C , respectively ; P < 0.001 ) . In group C more cycles were cancelled during the stimulation phase due to insufficient response , result ing in a lower percentage of oocyte retrievals ( 84 % , 73 % , and 63 % for groups A , B , and C ; P = 0.02 ) . However , women in group C obtained better quality embryos ( percentage of embryo score of 1 for best embryo , 29 % , 37 % , and 61 % for groups A , B , and C , respectively ; P = 0.008 ) , result ing in more transfers per oocyte retrieval ( 68 % , 71 % , and 90 % for groups A , B , and C , respectively ; P = 0.04 ) . After profound ovarian stimulation ( groups A and B ) only 7 % of the patients who retrieved four oocytes or less conceived , whereas after mild stimulation ( group C ) 67 % of these patients conceived ( P < 0.01 ) . Overall , no differences were found among the three groups comparing pregnancy rate per started IVF cycle . In conclusion , application of the described mild ovarian stimulation protocol result ed in pregnancy rates per started IVF cycle similar to those observed after profound stimulation with GnRH agonist cotreatment despite shorter stimulation and a 27 % reduction in exogenous FSH . A higher cancellation rate before oocyte retrieval was compensated by improved embryo quality concomitant with a higher chance of undergoing embryo transfer . A relatively low number of oocytes retrieved after mild ovarian stimulation distinctly differs from the pathological reduction in the number of oocytes retrieved after profound ovarian stimulation ( poor response ) associated with poor IVF outcome . The relatively small number of oocytes obtained after mild ovarian stimulation may represent the best of the cohort in a given cycle OBJECTIVE To assess the efficacy , safety , and local tolerance of ganirelix acetate for the inhibition of premature luteinizing hormone ( LH ) surges in women undergoing controlled ovarian hyperstimulation ( COH ) . DESIGN Phase III , multicenter , open-label r and omized trial . SETTING In vitro fertilization ( IVF ) centers in North America . PATIENT(S ) Healthy female partners ( n = 313 ) in subfertile couples for whom COH and IVF or intracytoplasmic s 
    Output:
    
REVIEW ER 'S CONCLUSIONS The new fixed GnRH antagonist protocol ( i.e. with antagonist start fixed on day 6 of gonadotrophin stimulation ) is a short and simple protocol with a significant reduction in incidence of severe OHSS but a lower pregnancy rate compared to the GnRH agonist long protocol .
There is a non significant difference between both protocol s regarding prevention of premature LH surge .
The clinical outcome may be further improved by developing more flexible antagonist regimens taking into account individual patient characteristics .