***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 if low-dose hCG is similar to hMG and to rFSH in the late follicular phase . STUDY DESIGN In a prospect i ve r and omized controlled trial , 51 patients undergoing controlled ovarian stimulation received ovarian priming with rFSH  and then received hCG ( 200 IU/day ) ( hCG group , n=17 ) , hMG ( 225 IU/day ) ( hMG group , n=17 ) or rFSH ( 200 IU/day ) ( FSH group , n=17 ) in the late stage of follicular development . Parameters of follicular response and serum estradiol , progesterone and testosterone levels were assessed . RESULTS Pre-ovulatory ovarian follicle occurrence and length of treatment were similar among the three treatment groups . Serum progesterone level on the day of pre-ovulatory hCG was significantly higher in the hCG group than in the hMG or rFSH group . Clinical pregnancy rates were similar for all groups . The total cost of treatment was significantly lower for the hCG group than for the groups supplemented with hMG or rFSH . CONCLUSIONS LH in the form of low-dose hCG during the late follicular phase induced the same follicular pattern as hMG and rFSH after ovulation induction . The procedure using hCG produced pregnancy rates similar to those obtained using hMG and rFSH , even though the patients showed higher serum progesterone levels on the hCG day The advent of recombinant DNA technology will soon produce for the market a product that has pure follicle-stimulating hormone ( pFSH ) but no luteinizing hormone . A prospect i ve r and omized study was performed to see if pFSH ( Metrodin ) was able to stimulate the same in vitro fertilization parameters as human menopausal gonadotropin when preceded by gonadotropin suppression by leuprolide acetate . The results showed similar parameters between the two drugs , i.e. , number of oocytes , number of embryos , endometrial thickness at time of human chorionic gonadotropin , fertilization rates and pregnancy rates in a protocol purpose ly design ed to stimulate as many follicles as safely as possible because of a shared oocyte and successful cryopreservation program BACKGROUND To test the effects of progressively decreasing dosages of exogenous LH we combined various amounts of HMG , containing FSH , LH and HCG , and highly purified ( HP ) FSH to treat 120 GnRH agonist-suppressed infertile female patients as c and i date s for controlled ovarian stimulation ( COS ) . METHODS Subjects were r and omly assigned to four treatment groups that received the following daily i.m . gonadotrophin regimens : A , FSH 150 IU only ; B , FSH 150 IU and LH activity 37.5 IU ; C , FSH 150 IU and LH activity 75 IU ; D , FSH 150 IU and LH activity 150 IU . FSH dose adjustments were allowed only after the 14th treatment day . Monitoring included  transvaginal ultrasound at 2-day intervals and daily determinations of LH , FSH , estradiol ( E(2 ) ) , progesterone , testosterone and HCG .  RESULTS Duration of COS was significantly shortened in patients receiving at least 75 IU daily of LH activity . Small ( < 10 mm diameter ) pre-ovulatory ovarian follicle occurrence was inversely correlated with LH activity dose administered ( r = -0.648 , P < 0.0001 ) and serum HCG levels ( r = -0.272 , P < 0.01 ) but not to serum LH levels . Serum testosterone levels were positively correlated to the LH activity dose administered ( r = 0.313 , P < 0.001 ) , while serum progesterone levels were positively correlated to the FSH dose administered ( r = 0.447 , P < 0.00001 ) but not to the LH activity dose administered . CONCLUSIONS Firstly , HCG content considerably contributes to HMG activity ; secondly , menotrophin LH activity content can reduce in a dose-dependent manner the occurrence of small pre-ovulatory follicles ; and finally , contrary to common belief , enhanced FSH stimulation rather than LH activity appears to cause premature follicle luteinization during COS Although FSH is essential to stimulate ovarian folliculogenesis , increasing physiological and clinical evidence suggests that moderate LH stimulation may also be critical for optimal follicle and oocyte development . Conversely , a clinical trend exists toward conducting controlled ovarian hyperstimulation ( COH ) in a LH-depleted environment , as recently developed gonadotropin preparations are devoid of LH activity , and endogenous LH is suppressed with GnRH analogs in most COH cycles . To investigate the role of LH activity during COH we supplemented highly purified ( HP ) FSH with low dose hCG in GnRH agonist-suppressed women . Twenty normoovulatory women were pretreated with a GnRH agonist  and after 2 weeks were r and omly assigned to receive HP FSH ( 150 IU/day ) alone ( group A ; 10 patients ) or combined with hCG ( 50 IU/day ; group B ; 10 patients ) . The HP FSH dose was increased after 14 days only in cases of inadequate response . Treatment was monitored with pelvic ultrasound and daily hormone determinations . None of the patients of group B and 8 of group A required more than 14 days of treatment and increments of the FSH dose . Folliculogenesis and 17beta-estradiol ( E2 ) secretion progressed more rapidly and evenly in group B. Although preovulatory follicle number and E2 concentrations were comparable , patients in group B required a shorter stimulation time ( 12.5+/-0.6 vs. 17.3+/-0.7 days in group A ; P < 0.0001 ) and a lower HP FSH dose ( 1725+/-84 vs. 2670+/-164 IU in group A ; P < 0.0001 ) . Serum levels of LH , E2 , progesterone , and testosterone did not differ between the 2 groups ; serum FSH was higher in group A. We conclude that LH activity promotes folliculogenesis in synergy with FSH in the mid- to late follicular phase and that low dose hCG coadministration optimizes COH by 1 ) enhancing FSH action , 2 ) accelerating ovarian follicle development , 3 ) shortening COH duration , 4 ) lowering HP FSH requirements , and 5 ) reducing COH cost . Thus , moderate LH activity in the follicular phase plays a positive physiological and clinical role in folliculogenesis and ovulation induction OBJECTIVES To clarify the endocrine mechanisms underlying the outcome of different ovulation induction regimens with gonadotropins and GnRH agonists ( GnRH-a ) . DESIGN Prospect i ve study . SETTING Reproductive Endocrinology Center , University of Bologna . PATIENTS Forty eumenorrheic women r and omly assigned to four groups of 10 subjects each . INTERVENTIONS Ovulation induction regimens : group A , purified FSH only ; group B , purified FSH and flare-up GnRH-a ; group C , purified FSH and long GnRH-a ; and group D , hMG and long GnRH-a . MAIN OUTCOME MEASURES Pelvic ultrasound and hormone levels in daily serum sample s and in follicular fluid drawn immediately before hCG administration . RESULTS Exogenous gonadotropin dose did not differ among groups . Group B had fewer preovulatory follicles than group C. Group B had higher serum LH , FSH , E2 , P , T , and follicular fluid LH , E2 , T , and alpha-inhibin than groups C and /or D. Groups C and D did not differ . CONCLUSIONS Long GnRH-a regimens improved follicle yield and the endocrine milieu in spite of comparable exogenous gonadotropin dose and lower serum FSH and thus appear to be preferable in assisted reproduction . Reduced folliculogenesis found in flare-up GnRH-a regimens could be mediated by the atretic effects of high intraovarian and rogens . Efficacy of purified FSH and hMG was comparable BACKGROUND LH activity may influence treatment response and outcome in IVF cycles . METHODS A r and omized , assessor-blind , multinational trial compared ongoing pregnancy rates ( primary end-point ) in 731 women undergoing IVF after stimulation with highly purified menotrophin ( HP-hMG ) ( n = 363 ) or recombinant FSH ( rFSH ) ( n = 368 ) following a long GnRH agonist protocol .  Patients received identical pre- and post-r and omization interventions . One or two embryos were transferred on day 3 . RESULTS More oocytes were retrieved ( P < 0.001 ) after rFSH treatment ( 11.8 ) compared with HP-hMG treatment ( 10.0 ) , but a higher proportion developed into top- quality embryos ( P = 0.044 ) with HP-hMG ( 11.3 % ) than with rFSH ( 9.0 % ) . At the end of stimulation , lower estradiol ( E(2 ) ) ( P = 0.031 ) and higher progesterone ( P < 0.001 ) levels were found with rFSH , even after adjusting for follicular response . The distribution of hypo- , iso- and hyper-echogenic endometrium showed a significant ( P = 0.023 ) shift towards the hyperechogenic pattern after rFSH treatment . The ongoing pregnancy rate per cycle was 27 % with HP-hMG and 22 % with rFSH [ odds ratio ( 95 % confidence interval ) : 1.25 ( 0.89 - 1.75 ) ] . CONCLUSION Superiority of HP-hMG over rFSH in ongoing pregnancy rate could not be concluded from this study , but non-inferiority was established . Pharmacodynamic differences in follicular development , oocyte/embryo quality , endocrine response and endometrial echogenicity exist between HP-hMG and rFSH preparations , which may be relevant for treatment outcome The effects of treatment of patients with gonadotrophin-releasing hormone analogue ( GnRHa ) combined with purified follicle stimulating hormone ( FSH ) for in-vitro fertilization ( IVF ) were investigated in detail to determine the influences of different administration routes and the degree of suppression of luteinizing hormone ( LH ) . Responses to exogenous gonadotrophins were studied in infertile women ( n = 60 ) with normal menstrual rhythm whose endogenous gonadotrophin activity was suppressed using a GnRHa in a long protocol . They were r and omized to receive i.m . administration of human menopausal gonadotrophins ( HMGim , Pergonal ) or purified follicle stimulating hormone ( FSH , Metrodin High Purity ) administered either i.m . ( MHPim ) or s.c . ( MHPsc ) . Responses were assessed by measuring plasma FSH , LH , oestradiol , testosterone and progesterone . After stimulation day 4 , the MHPsc group showed significantly higher circulating concentrations of FSH than either the MHPim or HMGim group . However , the HMG group showed significantly higher oestradiol concentrations after stimulation day 5 than either MHP group . The differences in circulating oestradiol concentrations in the MHP-treated patients appeared to be strongly influenced by the mean circulating concentrations of LH in the follicular phase . The patients who showed mean follicular phase LH concentrations of < 1 IU/l showed longer follicular phases , lower circulating oestradiol and testosterone concentrations and also lower follicular fluid concentrations of oestradiol and testosterone , indicating a reduction in the normal follicular metabolism of progesterone to and rogens and oestrogens under these conditions . This group of patients also showed longer follicular phases , which may have consequences for future clinical management BACKGROUND Elevated serum progesterone levels at the end of the follicular phase in controlled ovarian stimulation ( COS ) leads to a poorer ongoing pregnancy rate in IVF cycles due to reduced endometrial receptivity . The objective of this study was to use microarray technology to compare endometrial gene expression profiles at the window of implantation according to the levels of circulating progesterone . METHODS For this prospect i ve cohort study , microarray data were obtained from endometrial biopsies from 12 young healthy oocyte donors undergoing COS with pituitary suppression by either gonadotrophin-releasing hormone ( GnRH ) agonists or antagonists , and recombinant FSH .  On the day of recombinant chorionic gonadotrophin ( rCG ) administration , six women had serum progesterone levels ( P ) > 1.5 ng/ml ( study group ) and six had serum P levels < 1.5 ng/ml ( control group ) . Endometrial sample s were collected using a Pipelle catheter 7 days after the rCG injection . RESULTS Using the parametric test , we identified 140 genes significantly dysregulated ( 64 up- and 
    Output:
    
Analysis of confounding factors showed that the intensity of ovarian stimulation is the most important determining factor to explain serum progesterone elevation at the time of hCG administration , CONCLUSIONS This systematic review shows that providing LH activity supplementation in combination with FSH during ovarian stimulation does not have a consistent effect on serum progesterone concentrations at the time of hCG administration .
However , these data also suggest that , in accordance with physiological concept , the timing of LH activity administration could influence the impact on serum progesterone changes