***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 evaluate the effect of support with human chorionic gonadotrophin in the luteal phase in women taking part in an in vitro fertilisation programme after buserelin and human menopausal gonadotrophin were used to hyperstimulate their ovaries . DESIGN --Controlled group comparison . SETTING --Outpatient department of a private hospital . PATIENTS --115 Women with indications for in vitro fertilisation , all of whom had at least one embryo transferred . INTERVENTIONS --After suppression of the pituitary with buserelin the ovaries of all the women were stimulated with human menopausal gonadotrophin on day 4 of the luteal phase . Human chorionic gonadotrophin ( 10,000 IU ) was given to induce ovulation , and oocytes were recovered 34 hours later . Embryos were transferred 46 to 48 hours after insemination . Women who had received the 10,000 IU of human chorionic gonadotrophin on a date that was an uneven number ( n = 61 ) were allocated to receive support doses of 2500 IU human chorionic gonadotrophin three and six days after that date . The remaining 54 women did not receive hormonal support . END POINT -- Determination of the rates of pregnancy . MEASUREMENTS and main results --Support with human chorionic gonadotrophin did not significantly alter the progesterone or oestradiol concentrations in the early or mid-luteal phase . The mean ( range ) progesterone concentrations in the late luteal phase in women who did not become pregnant were , however , significantly higher in those who received support ( 16(9 - 110 ) nmol/l nu 8(4 - 46 ) nmol/l ) , and the luteal phase was significantly longer in this group ( 14 days nu 12 days ) . The rate of pregnancy was significantly higher in the women who received support than in those who did not ( 25/61 nu 8/54 ) . CONCLUSIONS --When buserelin and human menopausal gonadotrophin are used to hyperstimulate ovaries support with human chorionic gonadotrophin in the luteal phase has a beneficial effect on in vitro fertilisation This study aim ed to compare the efficacy of micronized progesterone administered as luteal support following ovulation induction for in-vitro fertilization (IVF)- embryo transfer in cycles using gonadotrophin-releasing hormone agonist  , either orally ( 200 mgx4/day ) or vaginally ( 100 mgx2/day ) and to characterize the luteal phase hormonal profile during such treatments . A total of 64 high responder patients requiring intracytoplasmic sperm injection due to male factor infertility were prospect ively r and omized into two treatment groups . Patients treated orally or vaginally were comparable in age ( 31.9 + /- 6.1 versus 30.6 + /- 5.2 ; mean + /- SD ) , number of oocytes retrieved  ( 17 + /- 8.2 versus 18 + /- 7.0 ) , and number  of embryos transferred  ( 3.1 + /- 1.2 versus 2.7 + /- 0.9 ) per cycle . Following low dose vaginal treatment , a significantly higher implantation rate ( 30.7 versus 10.7 % , P < 0.01 ) , but similar clinical pregnancy rate ( 47.0 versus 33.3 % ) and ongoing pregnancy rate ( 41.1 versus 20.0 % ) was observed , compared with oral treatment . In conception cycles , luteal serum progesterone and oestrogen concentrations did not differ between the treatment groups . In non-conception cycles , late luteal progesterone concentrations were significantly lower following vaginal treatment . As low dose micronized progesterone administered vaginally is simple , easy and well tolerated , it could be recommended as the method of choice for luteal support , especially for high responder patients at risk for ovarian hyperstimulation syndrome There is disagreement among in vitro fertilization ( IVF ) programs as to the need to administer exogenous progesterone to support the luteal phase of patients undergoing embryo transfer after IVF . We examined the effect on pregnancy rates of Prolution , 50-mg daily injections given on days 7–16 following oocyte recovery , in 186 women undergoing IVF treatment using a combined stimulation regime of clomiphene and human menopausal gonadotropin ( hMG ) .  One group was deliberately selected for treatment on the possible criterion of lutealphase deficiency and two other groups were r and omly selected into a treatment and a control group . No effect on pregnancy rate was noted in any of these groups . These results indicate that extension of the luteal phase with exogenous progesterone is unlikely to have a significant effect on increasing the pregnancy rate in IVF programs using similar treatment regimes Background . A prospect i ve study was done to compare the efficacy of luteal phase support ( LPS ) using either three times hCG  ( group I , n=77 ) , hCG on the day of embryo transfer ( ET ) in combination with daily vaginal progesterone  ( group II , n=62 ) or vaginal progesterone only  ( group III , n=70 ) BACKGROUND Traditional and largely qualitative review s of evidence are now giving way to much more structured systematic overviews that use a quantitative method to calculate the overall effect of treatment . The latter approach is dependent on the quality of primary studies , which may introduce bias if they are of poor method ologic quality . OBJECTIVE To test the hypothesis that the inclusion of poor- quality trials in meta-analyses would bias the conclusions and produce incorrect estimates of treatment effect . METHODS An overview of r and omized trials of antiestrogen therapy in subfertile men with oligospermia was performed to test the hypothesis . Data sources included online search ing of MEDLINE and Science Citation Index data bases between 1966 and 1994 , scanning the bibliography of known primary studies and review articles , and contacting experts in the field . After independent , blind assessment , nine of 149 originally identified studies met the inclusion criteria and were selected . We assessed study quality independently . Outcome data from each study were pooled and statistically summarized . RESULTS There was a marginal improvement in pregnancy rate with antiestrogen treatment ( odds ratio , 1.6 ; 95 % confidence interval , 0.9 to 2.6 ) . Sensitivity analyses on the basis of method ologic quality demonstrated that poor- quality studies produced a positive effect with treatment , whereas no benefit was observed with high- quality studies . CONCLUSION The results of a meta- analysis are influenced by the quality of the primary studies included . Method ologically , poor studies tend to exaggerate the overall estimate of treatment effect and may lead to incorrect inferences A total of 156 patients were r and omly treated with exogenous natural progesterone ( intramuscularly , 50 mg/day ) and vaginal gel ( 90 mg/day ) P or nothing ( Controls ) from the day before embryo transfer ( ET ) for two weeks . In case of positive beta-HCG , the treatment was continued for 12 weeks . Plasma P and 17 beta-Estradiol concentrations were estimated and compared with the control not supplemented group . Both treatments were able to increase significantly the luteal plasmatic values of P versus controls . The ongoing pregnancy and the living birth rates per transfer were significantly higher in the patients supplemented with intramuscular P than in those treated with vaginal gel P. The intramuscular natural P appears the most suitable route of administration for luteal phase support in IVF-ET procedures In a consecutive series of 167 patients reaching the stage of embryo transfer after in vitro fertilization and embryo transfer , 19 clinical pregnancies ensued . The serum progesterone ( P ) levels were significantly greater on the first and second ( P less than 0.01 ) and third ( P less than 0.05 ) postaspiration days for those who conceived . Higher circulating levels of P were achieved on days 1 , 2 , and 3 ( P less than 0.05 ) by the daily injection of P , 50 mg in oil , given for 5 consecutive days , beginning immediately after follicle aspiration . Both pregnancy and nonpregnancy cycles demonstrated high circulating P levels , but the study implies that relatively higher levels are required for conception , and such levels can be achieved by the use of intramuscular Fifty-two women , who had 62 ovum aspiration cycles , received a progesterone ( P ) supplementation of 100 mg/day that was initiated 10 hours before human chorionic gonadotropin ( hCG ) administration and was continued over the following 6 days . Forty-eight women who had 74 ovum pick-ups , but did not get P , served as controls . Forty-four ( 84.6 % ) women of the treatment group , and 40 ( 83.3 % ) of the controls had ovum fertilization and embryo replacement . The fertilization and cleavage rates and the mean number of replaced embryos per embryo transfer ( ET ) cycle did not differ between the groups . Endometrial biopsies , from treatment group women with no fertilized eggs , which were taken 48 hours after ovum pick-up , mostly revealed an " advanced endometrial dating , " in relation to the " day of hCG . " Pregnancy rate per ET cycle for the treatment group was significantly higher than that of the controls ; 41.2 % versus 23.3 % , respectively . It is concluded that the higher pregnancy rate result ed from an improvement in uterine receptivity Replacing GnRH agonist cotreatment for the prevention of a premature rise in LH during ovarian stimulation for in vitro fertilization ( IVF ) by the late follicular phase administration of GnRH antagonist may render supplementation of the luteal phase redundant , because of the known rapid recovery of pituitary function after antagonist cessation . This r and omized two-center study was performed to compare nonsupplemented luteal phase characteristics after three different strategies for inducing final oocyte maturation . Forty patients underwent ovarian stimulation using recombinant (r-)FSH ( 150 IU/d , fixed ) combined with a GnRH antagonist ( antide ; 1 mg/d ) during the late follicular phase . When at least one follicle above 18 mm was observed , patients were r and omized to induce oocyte maturation by a single injection of either r-human (h)CG ( 250 microg ) ( n = 11 ) , r-LH ( 1 mg ) ( n = 13 ) , or GnRH agonist ( triptorelin ; 0.2 mg ) ( n = 15 ) . Retrieved oocytes were fertilized by either IVF or intracytoplasmatic sperm injection , depending on sperm quality . Embryo transfer was performed 3 - 4 d after oocyte retrieval . No luteal support was provided . Serum concentrations of FSH , LH , estradiol ( E(2 ) ) , progesterone ( P ) , and hCG were assessed at fixed intervals during the follicular and luteal phase . The median duration of the luteal phase was 13 , 10 , and 9 d for the r-hCG , the r-LH , and the GnRH agonist group , respectively ( P = 0.005 ) . The median area under the curve per day ( from 4 d post r and omization until the onset of menses ) for LH was 0.50 , 2.34 , and 1.07 for the r-hCG , the r-LH , and the GnRH agonist group , respectively ( P = 0.001 ) . The median area under the curve per day for P was 269 vs. 41 and 16 for the r-hCG , the r-LH , and the GnRH agonist group , respectively ( P < 0.001 ) . Low pregnancy rates ( overall , 7.5 % ; range , 0 - 18 % per started cycle ) were observed in all groups . In conclusion , the nonsupplemented luteal phase was insufficient in all three groups . In the patients receiving r-hCG , the luteal phase was less disturbed , compared with both other groups , presumably because of prolonged clearance of hCG from the circulation and the result ing extended support of the corpus luteum . Despite high P and E(2 ) concentrations during the early luteal phase in all three groups , luteolysis started prematurely , presumably because of excessive negative steroid feedback result ing in suppressed pituitary LH release . Hence , support of corpus luteum function remains m and atory after ovarian stimulation for IVF with GnRH antagonist cotreatment A polysyloxane vaginal ring containing 1 g of natural progesterone was developed as luteal supplementation for women treated with IVF-embryo transfer and for agonadal women participating in an oocyte donation programme . The ring provides continuous release of progesterone ( 10 - 20 nmol/l ) for 90 days . The efficacy of this form of progesterone supplementation was evaluated in two multicentre prospect i ve r and omized trials . IVF-embryo transfer trial : After oocyte aspiration , 505 women were r and omly allocated to progesterone supplementation with vaginal ring or i.m . progesterone ( 50 mg/day ) . The clinical pregnancy rate was 36.6 % in both groups . Implantation rate was 15.9 % in the vaginal ring and 16.0 % in i.m . progesterone . Oocyte donation trial : After endometrial proliferation with micronized 
    Output:
    
Comparing routes of progesterone administration , reductions in clinical pregnancy rate with the oral route , compared to the intramuscular or vaginal routes , did not reach statistical significance , but there was evidence of benefit of the intramuscular over the vaginal route for the outcomes of ongoing pregnancy and live birth .
No significant difference in pregnancy rate was observed between vaginal progesterone gel and other types of vaginal progesterone .
REVIEW ERS ' CONCLUSIONS Luteal phase support with hCG or progesterone after assisted reproduction results in an increased pregnancy rate .
hCG does not provide better results than progesterone , and is associated with a greater risk of OHSS when used with GnRHa .