***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: PURPOSE To develop guidance to practicing oncologists about available fertility preservation methods and related issues in people treated for cancer . METHODS An expert panel and a writing committee were formed . The questions to be addressed by the guideline were determined , and a systematic review of the literature from 1987 to 2005 was performed , and included a search of online data bases and consultation with content experts . RESULTS The literature review found many cohort studies , case series , and case reports , but relatively few r and omized or definitive trials examining the success and impact of fertility preservation methods in people with cancer . Fertility preservation methods are used infrequently in people with cancer . RECOMMENDATIONS As part of education and informed consent before cancer therapy , oncologists should address the possibility of infertility with patients treated during their reproductive years and be prepared to discuss possible fertility preservation options or refer appropriate and interested patients to reproductive specialists . Clinician judgment should be employed in the timing of raising this issue , but discussion at the earliest possible opportunity is encouraged .  Sperm and embryo cryopreservation  are considered st and ard practice and are widely available ; other available fertility preservation methods should be considered investigational and be performed in centers with the necessary expertise . CONCLUSION Fertility preservation is often possible in people undergoing treatment for cancer . To preserve the full range of options , fertility preservation approaches should be considered as early as possible during treatment planning BACKGROUND Use of letrozole , a selective inhibitor of aromatase , reduces the gonadotrophin dose required to induce follicular maturation . We evaluated whether incorporation of letrozole could be an effective low-cost IVF protocol for poor responders . METHODS A r and omized , controlled , single-blind trial was conducted in the Assisted Reproduction Unit , Institute of Reproductive Medicine , Kolkata , India . Thirty-eight women with a history of poor ovarian response to gonadotrophins were recruited . Thirteen women ( Let-FSH group ) received letrozole 2.5 mg daily from day 3 - 7 , and recombinant FSH ( rFSH ) 75 IU/day on days 3 and 8 ; and 25 women ( GnRH-ag-FSH group ) underwent long GnRH agonist protocol and stimulated with rFSH ( 300 - 450 IU/day ) . Ovulation was triggered by 10,000 IU of HCG followed by IVF-embryo transfer . The main outcome measures were total dose of rFSH ( IU/cycle ) , terminal estradiol ( E2 ) ( pg/ml ) , numbers of follicles , oocytes retrieved and transferable embryo , endometrial thickness ( mm ) , and pregnancy rate . RESULTS Compared with the GnRH-ag-FSH group ( 2865 + /- 228 IU ) , the Let-FSH group ( 150 + /- 0 IU ) received a significantly ( P < 0.001 ) lower total dose of FSH .  Except for terminal E2 , which was significantly higher ( P < 0.001 ) in the GnRH-ag-FSH group ( 380 + /- 46 pg/ml ) than the Let-FSH group ( 227 + /- 45 pg/ml ) , the treatment outcomes in all other respects , including pregnancy rate , were statistically comparable . CONCLUSIONS Adjunctive use of letrozole may form an effective means of low-cost IVF protocol in poorly responding women BACKGROUND Medical induction of ovulation using clomiphene citrate ( CC ) as first line and exogenous gonadotrophins as second line forms the classical treatment algorithm in normogonadotrophic anovulatory infertility . Because the chances of success following classical ovulation induction are not well established , a shift in first-line therapy can be observed towards alternative treatment . The study aim was to : ( i ) reliably assess the probability of singleton live birth following classical induction of ovulation ; and ( ii ) construct a prediction model , based on individual patient characteristics assessed upon st and ardized initial screening , to help identify patients with poor chances of success . METHODS A total of 240 consecutive women visiting a specialist academic fertility unit with a history of infertility , oligomenorrhoea or amenorrhoea , and normal FSH and estradiol serum concentrations ( WHO group 2 ) was prospect ively followed . The women had not been previously treated with ovulation-inducing agents . All patients commenced with CC . Patients who did not ovulate within three treatment cycles of incremental daily doses up to 150 mg for 5 consecutive days or ovulatory CC patients who did not conceive within six cycles , subsequently underwent gonadotrophin induction of ovulation applying a step-down dose regimen . The main outcome measure was pregnancy result ing in singleton live birth . Cox regression was used to construct a multivariable prediction model . RESULTS Overall , there were 134 pregnancies ending in a singleton live birth ( 56 % of women ) . The cumulative pregnancy rate after 12 and 24 months of follow-up was 50 % and 71 % respectively . Polycystic ovary syndrome ( PCOS ) patients ( 49 % ) , clearly non-PCOS patients ( 13 % ) and the in-between group did not differ in prognosis ( P = 0.9 ) . The multivariable Cox regression model contained the woman 's age , the insulin : glucose ratio and duration of infertility . With a cut-off value of 30 % for low chance , the model predicted probabilities at 12 months lower than this cut-off for 25 out of 240 patients ( 10.4 % ) . CONCLUSIONS Classical ovulation induction produces very good results in normogonadotrophic anovulatory infertility . Alternative treatment options may not be indicated as first-line therapy in these patients , except for subgroups with poor prognosis . These women can be identified by older age , longer duration of infertility and higher insulin : glucose ratio OBJECTIVE To determine the serum concentrations of enclomiphene and zuclomiphene across consecutive cycles of clomiphene citrate treatment in anovulatory infertile women . DESIGN Prospect i ve cohort . SETTING Tertiary institutional infertility clinic . PATIENT(S ) Fourteen consenting anovulatory infertile women receiving st and ardized , cyclic , incremental treatment with clomiphene citrate for ovulation induction . INTERVENTION(S ) Clomiphene citrate treatment ( 50 - 150 mg/d , cycle days 5 - 9 ) , titrated to the minimum effective ovulation-inducing dose , was administered for three to six total cycles . Blood sample s were obtained on cycle days 3 and 10 in each treatment cycle . MAIN OUTCOME MEASURE(S ) Serum concentrations of enclomiphene and zuclomiphene . RESULT ( S ) Cycle day 3 zuclomiphene levels were below assay limits in all initial cycles , increased progressively across three consecutive cycles , and thereafter plateaued . Cycle day 3 enclomiphene concentrations were uniformly undetectable . Cycle day 10  enclomiphene levels increased with dose administered , but these observations were not statistically significant . CONCLUSION ( S ) Clomiphene citrate induction of ovulation results in an isomer-specific systemic accumulation of zuclomiphene across consecutive cycles of treatment . The combined maximum concentration of enclomiphene and zuclomiphene attained in practice approximates 100 nmol/L and is generally well below levels previously demonstrated to have adverse effects in vitro Letrozole was compared with clomiphene citrate ( CC ) as a first-line treatment for ovulation induction in women with polycystic ovaries ( PCOs ) . A total of 106 women with primary infertility and a diagnosis of PCOs were r and omized to receive either 100 mg CC ( n = 55 ) or 2.5 mg letrozole ( n = 51 ) daily for 5 days . Human chorionic gonadotrophin ( hCG ) at a dose of 10 000 IU was administered when at least one follicle with a mean diameter ≥ 18 mm was observed using transvaginal ultrasound . The number of mature follicles was significantly lower , but endometrial thickness and ovulation and pregnancy rates were significantly higher in the letrozole group than in the CC group . In conclusion , letrozole is associated with a higher pregnancy rate than CC in PCO patients and may have a role as a first-line treatment for anovulatory patients with PCOs BACKGROUND To compare the clinical results and the cost-effectiveness of using the aromatase inhibitor , letrozole , in conjunction with FSH and FSH alone for controlled ovarian stimulation ( COS ) in patients undergoing intrauterine insemination ( IUI ) for a variety of indications . METHODS Four hundred and thirty-two consecutive patients who underwent 872 IUI cycles were included . The study population was composed of two groups . Group I included 308 patients who underwent 589 IUI cycles with letrozole and FSH for the following indications : anovulation ( 143 cycles ) , male factor infertility ( 147 cycles ) , unexplained infertility ( 250 cycles ) , endometriosis ( 18 cycles ) and combined indications ( 31 cycles ) . Group II included 124 patients who underwent 283 IUI cycles who received FSH only  for the following indications : ovarian factor infertility ( 82 cycles ) , male factor infertility ( 66 cycles ) , unexplained infertility ( 114 cycles ) , endometriosis ( 13 cycles ) and other indications ( 8 cycles ) . Main outcome measures included number of mature follicles > 16 mm in diameter , dose of FSH used per cycle , clinical pregnancy rate and cost-effectiveness ratio per pregnancy . RESULTS  FSH dose required for ovarian stimulation was significantly lower when letrozole was used ( P < 0.0001 ) . Although a significantly higher number of follicles > 16 mm and endometrial thickness at the day of hCG administration ( P < 0.0001 ) were observed in Group II , pregnancy rate per started ( 14.4 versus 15.9 % ) and per completed cycles ( 15.77 versus 18.07 % ) was the same in Group I and Group II , respectively . IUI cancellation rate was significantly lower with letrozole treatment ( P = 0.05 % ) . The cost per cycle was significantly lower in Group I versus Group II ( 468.93 Can dollars + /- 418.18 versus 1067.28 + /- 921.43 ; P < 0.0001 ) . The cost-effectiveness ratio was 3249.42 dollars in the letrozole group and 6712.00 dollars in the FSH-only group . CONCLUSION A letrozole-FSH combination could be an effective ovarian stimulation protocol in IUI cycles . Such a protocol may be more cost-effective than FSH alone because of the difference of FSH dose and cost . A r and omized controlled trial is needed to further substantiate this finding OBJECTIVE To study the effects of clomiphene citrate ( CC ) on the endometrium of regularly cycling women . DESIGN Prospect i ve , controlled study . SETTING Department of Obstetrics and Gynaecology , Faculty of Medicine , Chulalongkorn University , Bangkok , Thail and . PATIENT(S ) Thirty healthy , regularly cycling , female volunteers . INTERVENTION(S ) All volunteers were studied for two consecutive cycles , one control cycle and one CC-treated cycle . Clomiphene citrate ( 100 mg/d ) was given on days 3 - 7 of the CC-treated cycles . Ultrasonography was performed daily to assess ovulation . Ultrasonography and endometrial biopsy were performed , and blood sample s were obtained for determination of E2 and progesterone levels 7 days after ovulation in both the control and CC-treated cycles . MAIN OUTCOME MEASURE(S ) Histologic dating , morphometric analysis , and ultrasonographic appearance and thickness of the endometrium . RESULT ( S ) Histologic dating and ultrasonographic appearance and thickness of the endometrium were similar in the control and CC-treated cycles , but morphometric parameters were different . The number of gl and s per square millimeter and the mean diameter of the gl and s were lower in the CC-treated cycles than in the control cycles , but the number of vacuolated cells per 1,000 gl and ular cells was higher . CONCLUSION ( S ) Clomiphene citrate has effects on the endometrium of regularly cycling women , as demonstrated by a reduction in gl and ular density and an increase in the number of vacuolated cells OBJECTIVE To evaluate the ovarian follicular dynamics of cycle modification with the aromatase inhibitor letrozole compared with clomiphene citrate in normal ovulatory women . DESIGN R and omized double-blind controlled trial . SETTING Tertiary care hospital . PATIENT(S ) Nineteen ovulatory female volunteers , ages 18 - 35 years . INTERVENTION(S ) Subjects were monitored in one control cycle . Subjects then received either letrozole 2.5 mg daily or clomiphene citrate 50 mg daily on days 5 - 9 after menses . MAIN OUTCOME MEASURE(S ) Number of mature follicles , endometrial thickness and endometrial pattern at ovulation , and follicular profiles of LH , FSH , and E(2 ) . RESULT ( S ) The number of mature follicles at the LH surge in natural cycles was 1.0 with an exaggerated response seen for treatment both with clomiphene and letrozole . There was no difference in the endometrial thickness at midcycle during either the natural cycles or the medicated cycles . LH surges and 
    Output:
    
CONCLUSIONS Letrozole is as effective as other methods of ovulation induction .