GnRH agonist versus GnRH antagonist in oocyte donation cycles: a prospective randomized study

BACKGROUND: The specific role of LH in folliculogenesis and oocyte maturation is unclear. GnRH antagonists, when administered in the late follicular phase, induce a sharp decrease in serum LH which may be detrimental for IVF outcome. This study was performed to evaluate whether the replacement of GnRH agonist (triptorelin) by a GnRH antagonist (ganirelix; NV Organon) in oocyte donation cycles has any impact on pregnancy and implantation rates. METHODS: A total of 148 donor IVF cycles was randomly assigned to use either a GnRH antagonist daily administered from the 8th day of stimulation (group I) or a GnRH agonist long protocol (group II) for the ovarian stimulation of their donors. The primary endpoints were the pregnancy and the implantation rates. RESULTS: The clinical pregnancy rate per transfer (39.72%, 29/73 versus 41.33%, 31/75) based on transvaginal scan findings at 7 weeks of gestation, the implantation rate (23.9 versus 25.4%) and the first trimester abortion rate (10.34 versus 12.90%) were similar in the two groups. CONCLUSION: In oocyte donation cycles the replacement of GnRH agonist by a GnRH antagonist appears to have no impact on the pregnancy and implantation rates when its administration starts on day 8 of stimulation.     

Comparison between a GnRH antagonist and a GnRH agonist flare-up protocol in oocyte donors: a randomized clinical trial

BACKGROUND: Little information is available on the outcome of controlled ovarian hyperstimulation (COH) using GnRH antagonist in oocyte donation cycles especially in comparison with the short GnRH agonist protocol. This study was aimed at comparing the two stimulation protocols in oocyte donation (OD) cycles. METHODS: A total of 113 donors randomly received COH using either GnRH antagonist or GnRH agonist. The primary endpoint was the mean number of mature oocytes retrieved per started donor cycle. Secondary endpoints were the mean number of cumulus-oocyte-complexes (COCs) retrieved, the mean proportion of mature oocytes, pregnancy and implantation rates in recipients. RESULTS: Oocytes were distributed to 166 recipients. The mean number (+/- SD) of COC (11.6 +/- 5.8 versus 12.1 +/- 6.7), mature oocytes (8.4 +/- 4.4 versus 8.9 +/- 5.3) and the proportion of mature oocytes (70.8 versus 75.7%) retrieved per started donor cycle were similar in the antagonist and agonist groups, respectively. The implantation rate (26.1 versus 30.1%), clinical (40.2 versus 45.6%) and ongoing pregnancy rate per recipient cycle (32.2 versus 37.9%) were comparable in antagonist and agonist protocols, respectively. CONCLUSIONS: Similar mean number of mature oocytes and comparable pregnancy rates are achieved after OD in which donors received COH using GnRH antagonist or short GnRH agonist protocols.     

GnRH antagonist versus long GnRH agonist protocol in poor responders undergoing IVF: a randomized controlled trial

BACKGROUND. This is the first published report of a prospective, randomized, controlled trial comparing a fixed, multi-dose GnRH antagonist protocol with a long GnRH agonist protocol in poor responders undergoing IVF. METHODS. Sixty-six poor responders were randomized into two groups: the study group received 0.25 mg of cetrorelix daily starting on day 6 of stimulation; the control group received 600 microg of buserelin acetate daily starting in the mid-luteal phase of the preceding cycle. Both groups were given a fixed dose of recombinant FSH (300 IU daily) for stimulation. RESULTS. There were no significant differences in the cycle cancellation rates, duration of stimulation, consumption of gonadotrophins, and mean numbers of mature follicles, oocytes and embryos obtained. The implantation rates were similar, but the number of embryos transferred was significantly higher for the antagonist group (2.32 +/- 0.58 versus 1.50 +/- 0.83; P = 0.01). The pregnancy rates were also higher in the antagonist group, but the difference was not statistically significant. CONCLUSION. A fixed multi-dose GnRH antagonist protocol is feasible for patients who are poor responders on a long agonist protocol; however, our study failed to demonstrate an overall improvement in ovarian responsiveness. Clinical outcomes may be improved by developing more flexible antagonist regimens, an approach that requires further evaluation.     

Timing luteal phase support in GnRH agonist down-regulated IVF/embryo transfer cycles

BACKGROUND: The aim of this study was to compare the effect of three different times of onset of luteal phase support on ongoing pregnancy rate in infertile patients undergoing treatment with GnRH down-regulated IVF and embryo transfer (IVF/ET). MATERIALS AND METHODS: All consecutive eligible patients planned to undergo their first IVF treatment cycle were randomly allocated to receive vaginal progesterone as luteal support at three different time points, that is, after HCG administration for final oocyte maturation (HCG group), at the day of oocyte retrieval (OR group) or at the day of ET (ET group). The primary endpoint of this study was ongoing pregnancy rate. RESULTS: A total of 385 women were randomized, 130 were allocated to the HCG group, 128 to the OR group and 127 to the ET group. An ongoing pregnancy rate of 20.8% was found in the HCG group versus 22.7 and 23.6% in the OR group and ET group, respectively. The mean number and quality of the retrieved oocytes and the transferred embryos did not differ. CONCLUSION: Based on this data, an 18% difference in ongoing pregnancy rate between the three different times of onset of luteal phase support in GnRH agonist down-regulated IVF/ET cycles can be refuted. Smaller clinically meaningful differences may be present.     

Empty follicle syndrome: evidence for recurrence

The empty follicle syndrome (EFS) is a frustrating conditionin which no oocytes are retrieved in an IVF cycle. Althoughthis is an infrequent event in IVF patients, the economic consequencesas well as the emotional frustration of a cancelled cycle dueto the inability to obtain oocytes are enormous. The mechanismsresponsible for EFS remain obscure, though many hypotheses havebeen put forward ranging from dysfunctional folliculogenesisto a drug-related problem. We found that the EFS is a rare event(1.8% of oocyte retrievals) but with profound implications forcounselling the couple about their future reproductive performance.The chances of recurrence of EFS increase with the age of thepatient (24% recurrence rate for the 35–39 year age group,and 57% for those over 40 years). We postulate that ovarianageing, through altered folliculogenesis, may be implicatedin the aetiology of EFS and its recurrence.     

Empty follicle syndrome due to human errors: its occurrence in an in-vitro fertilization programme

We report five cases in which no oocytes were retrieved afterstandard ovarian stimulation for in-vitro fertilization (IVF),and in which it was found that mistakes had been made at thetime of human chorionic gonadotrophin (HCG) administration.In all five cases, oocyte retrieval was achieved after injectingHCG, when necessary, and reprogramming aspiration 24–36h later. A mean of 7 ± 3.2 MII oocytes were recoveredper patient and 3.2 ± 0.8 embryos were transferred. Threeclinical pregnancies were obtained, and four healthy infantswere born. In our programme, these were the only cases of emptyfollicle syndrome (EFS) that appeared over a total of 1118 cycles,and were all explained by human error in the administrationof HCG. Our experience shows that human error could be considereda significant factor in the aetiology of empty follicle syndrome,and that EFS may be in part avoided by taking simple preventivemeasures.     

The effect of an individualized GnRH antagonist protocol on folliculogenesis in IVF/ICSI

BACKGROUND: The aim of this study was to assess the effect of an individualized GnRH antagonist regimen on folliculogenesis. METHODS: In a multicentre, randomized, clinical trial, IVF/ICSI patients were allocated to a standard regimen, in which they received daily 0.25 mg GnRH antagonist ganirelix (Orgalutran) from the 6th day of stimulation onward (fixed regimen n = 102) or to an individualized regimen, in which IVF/ICSI patients received daily 0.25 mg GnRH antagonist starting on the day that the dominant follicle had reached a diameter of > or = 15 mm (flexible regimen n = 103). The primary endpoint was to assess the difference in the total number of oocytes. RESULTS: The mean (SD) number of retrieved oocytes was not statistically significantly different: 9.4 (5.8) in the flexible group versus 9.7 (6.5) in the fixed group. The clinical and ongoing pregnancy rates were 22.7 and 21.8% respectively in the flexible group versus 33 and 31.1% in the fixed group [relative rate ratio 0.69 (95% confidence interval 0.44-1.08) and 0.7 (0.44-1.12) respectively]. CONCLUSION: The individualized flexible regimen did not result in an increase in the total number of oocytes obtained.     

GnRH agonist (buserelin) or hCG for ovulation induction in GnRH antagonist IVF/ICSI cycles: a prospective randomized study

BACKGROUND: We aimed to determine the efficacy of ovarian hyperstimulation protocols employing a GnRH antagonist to prevent a premature LH rise allowing final oocyte maturation and ovulation to be induced by a single bolus of either a GnRH agonist or hCG. METHODS: A total of 122 normogonadotrophic patients following a flexible antagonist protocol was stimulated with recombinant human FSH and prospectively randomized (sealed envelopes) to ovulation induction with a single bolus of either 0.5 mg buserelin s.c. (n = 55) or 10,000 IU of hCG (n = 67). A maximum of two embryos was transferred. Luteal support consisted of micronized progesterone vaginally, 90 mg a day, and estradiol, 4 mg a day per os. RESULTS: Ovulation was induced with GnRH agonist in 55 patients and hCG in 67 patients. Significantly more metaphase II (MII) oocytes were retrieved in the GnRH agonist group (P < 0.02). Significantly higher levels of LH and FSH (P < 0.001) and significantly lower levels of progesterone and estradiol (P < 0.001) were seen in the GnRH agonist group during the luteal phase. The implantation rate, 33/97 versus 3/89 (P < 0.001), clinical pregnancy rate, 36 versus 6% (P = 0.002), and rate of early pregnancy loss, 4% versus 79% (P = 0.005), were significantly in favour of hCG. CONCLUSIONS: Ovulation induction with a GnRH agonist resulted in significantly more MII oocytes. However, a significantly lower implantation rate and clinical pregnancy rate in addition to a significantly higher rate of early pregnancy loss was seen in the GnRH agonist group, most probably due to a luteal phase deficiency.     

IVF pregnancy after induction of an ovulatory endogenous gonadotrophin surge using an LHRH agonist nasal spray

A successful human twin IVF pregnancy is reported after using a single 50 micrograms dose of LHRH agonist nasal spray (Buserelin) to induce an ovulatory endogenous gonadotrophin surge 34 h prior to oocyte collection. The couple had 10 years of primary male factor infertility, associated with significant anti-sperm antibodies. The clinical features and endocrine profile are presented.     

A lower ongoing pregnancy rate can be expected when GnRH agonist is used for triggering final oocyte maturation instead of HCG in patients undergoing IVF with GnRH antagonists

BACKGROUND: Eliciting an endogenous LH surge by GnRH-agonist for the induction of final oocyte maturation may be more physiological compared with the administration of HCG. However, the efficacy of this intervention in patients treated for IVF with GnRH antagonists remains to be assessed. METHODS: 106 patients were randomized to receive either 10 000 IU urinary HCG or 0.2 mg Triptorelin for triggering final oocyte maturation. Ovarian stimulation for IVF was performed with a fixed dose of 200 IU recombinant FSH and GnRH antagonist was started on stimulation day 6. Luteal phase was supported with micronized vaginal progesterone and oral estradiol. The study was monitored continuously for safety and stopping rules were established. RESULTS: No significant differences were present in the number of cumulus-oocyte complexes retrieved, in the proportion of metaphase II oocytes, in fertilization rates or in the number and quality of the embryos transferred between the two groups. However, a significantly lower probability of ongoing pregnancy in the GnRH agonist arm prompted discontinuation of the trial, according to the stopping rules established (odds ratio 0.11; 95% confidence interval 0.02-0.52). CONCLUSIONS: Lower probability of ongoing pregnancy can be expected when GnRH agonist is used for triggering final oocyte maturation instead of HCG in patients undergoing ovarian stimulation for IVF with GnRH antagonists.     

Addition of GnRH antagonist in cycles of poor responders undergoing IVF

Concern about the use of gonadotrophin-releasing hormone (GnRH) agonists in ovarian stimulation of poor responder IVF patients has arisen from the claim that GnRH agonists might have a direct deleterious effect through their receptors on the ovary. In this study, we compared two ovarian stimulation protocols in which no GnRH agonists were used. In all, 40 patients with a poor response in previous treatment cycles were included. They were divided into two groups: group I (n = 20) received ovarian stimulation for 20 cycles, without the addition of either GnRH agonist or antagonist; while group II (n = 20) patients received ovarian stimulation for 20 cycles, including the administration of a GnRH antagonist (Cetrorelix, 0.25 mg daily) during the late follicular phase. There was no statistically significant difference between the groups for mean age, duration of infertility, baseline FSH concentration, cancellation rate, number of ampoules of gonadotrophin used, number of mature oocytes retrieved, oestradiol concentrations on the day of injection of human chorionic gonadotrophin (HCG), fertilization rate and number of embryos transferred. The clinical pregnancy and implantation rates in group II appeared higher than in group I, but were not significantly different (20 and 13.33% compared with 6.25 and 3.44% respectively). The addition of GnRH antagonists to ovarian stimulation protocols might be a new hope for poor responder IVF patients, but this report is preliminary and further controlled randomized prospective studies with larger sample sizes are required.     

Dose-finding study of daily GnRH antagonist for the prevention of premature LH surges in IVF/ICSI patients: optimal changes in LH and progesterone for clinical pregnancy

BACKGROUND: An optimal range of LH concentrations for achieving pregnancy has not been established. The aim of this study was to investigate the effect of various LH levels induced by different GnRH antagonist doses on IVF outcome. METHODS: This was a prospective, single centre study including 144 IVF patients, stimulated with recombinant FSH from cycle day 2, and co-treated with daily GnRH antagonist (antide/Iturelix) (2 mg/2 ml, 1 mg/ml, 0.5 mg/ml, 0.5 mg/0.5 ml or 0.25 mg/ml) from cycle day 7 onwards. Serum samples were taken three times daily. RESULTS: Clinical pregnancies were only observed within a particular range of change in LH levels. The upper and lower thresholds for the mean LH area under the curve (AUC), adjusted for the baseline LH level before the antagonist was started (LH AUC(-S6); S6=stimulation day 6) were -2.2 and 12.4 (IU/l) respectively (a negative value=below baseline levels). There were no clinical pregnancies outside these threshold values. Similar results were found for progesterone, the threshold levels of progesterone AUC(-S6) were 3.98 and -1.21 ng/ml. Moreover, there were no pregnancies with progesterone levels >0.26 ng/ml/follicle on the day of hCG. CONCLUSIONS: Excessive or insufficient suppression of LH and progesterone levels during GnRH antagonist administration and high progesterone/follicle on hCG day seems to be associated with impaired clinical pregnancy rates.     

A relative reduction in mid-follicular LH concentrations during GnRH agonist IVF/ICSI cycles leads to lower live birth rates

BACKGROUND: The effect of early- and mid-follicular LH concentrations on the ovarian response and pregnancy outcomes was evaluated in women receiving pituitary down-regulation with a GnRH agonist and ovarian stimulation with recombinant FSH (rFSH) during IVF/ICSI treatment. METHODS: Blood samples were collected prospectively from 701 cycles (560 patients) of assisted reproduction and analysed retrospectively. On the basis of LH concentrations on stimulation day 7/8, the patients were divided into two groups: LH<1.2 IU/l (n=179) and LH>or=1.2 IU/l (n=522). Cycle outcomes were also compared on the basis of a ratio of mid- to early-follicular LH concentrations (0.5, n=491). RESULTS: Patients with low LH concentrations were found to have a significant reduction in the late-follicular estradiol concentrations (P<0.001), the number of oocytes retrieved (P<0.01) and the number of usable embryos (P<0.01), and they required significantly more rFSH (430 IU difference, P<0.01). These differences did not translate into a significant change in live birth rates. Conversely, a ratio of or=50%) was associated with a significant reduction in live birth rates per embryo transfer and per cycle started (27.3 versus 19.0%, P<0.05 and 22.2 versus 15.8%, P<0.05, respectively). CONCLUSIONS: Low mid-follicular levels of LH have a significant impact on ovarian response but not on live birth rates. A fall in LH level of >or=50% from the early- to mid-follicular phase resulted in a lower live birth rate.     

Comparison of LH concentrations in the early and mid-luteal phase in IVF cycles after treatment with HMG alone or in association with the GnRH antagonist Cetrorelix

Luteinizing hormone (LH) is mandatory for the maintenance of the corpus luteum. Ovarian stimulation for IVF has been associated with a defective luteal phase. The luteal phases of two groups of patients with normal menstrual cycles and no endocrinological cause of infertility were retrospectively analysed in IVF cycles. Thirty-one infertile patients stimulated with human menopausal gonadotrophins (HMG) for IVF to whom the gonadotrophin-releasing hormone (GnRH) antagonist Cetrorelix 0.25 mg was also administered to prevent the LH surge (group I) were compared with 31 infertile patients stimulated with HMG alone (group II). Despite differences in the stimulation outcome, luteal LH serum concentrations were similar in the two groups. LH values dropped from 2.3 +/- 1 IU/l on the day of human chorionic gonadotrophin (HCG) administration to 1.1 +/- 0.7 IU/l on day HCG +2 in group I (P < 0.0001) and from 5.1 +/- 3 to 1.2 +/- 1.7 IU/l (P < 0.0001) in group II. In the mid-luteal phase, LH concentrations were low in both groups. Our results suggest that suppressed LH concentrations in the early and mid-luteal phase may not be attributed solely to the GnRH-antagonist administration. Pituitary LH secretion may be inhibited by supraphysiological steroid serum concentrations via long-loop feedback and/or by the central action of the exogenously administered HCG via a short-loop mechanism.     

GnRH agonist for triggering final oocyte maturation in the GnRH antagonist ovarian hyperstimulation protocol: a systematic review and meta-analysis

Triggering final oocyte maturation with GnRH agonist during ovarian stimulation is feasible when inhibition of premature LH surge is performed with GnRH antagonists, and we aimed to systematically collate evidence on the clinical efficacy of GnRH agonist triggering in patients undergoing assisted reproduction in GnRH antagonist protocols. Twenty-three publications were identified by a comprehensive literature search that included PubMed, Embase and the Cochrane Library. Three publications out of 23 fulfilled the inclusion criteria for meta-analysis, which were (i) prospective, randomized controlled study design; (ii) stimulation with gonadotropins for induction of multifollicular development; (iii) suppression of endogenous LH by a GnRH antagonist; (iv) triggering of final oocyte maturation with GnRH agonist; (v) control group randomized to receive HCG for final oocyte maturation and (vi) any means of luteal phase support other than HCG. The participants were normoovulatory women undergoing IVF. The outcomes assessed were clinical pregnancy per randomized patient; number of oocytes retrieved; proportion of metaphase II oocytes; fertilization rate; embryo quality score; first trimester abortion rate; ovarian hyperstimulation syndrome (OHSS) incidence. Results are presented as combined standardized differences of the mean and combined odds ratios, as appropriate, with 95% confidence intervals. No significant difference was found for the number of oocytes retrieved (-0.94, -0.33-0.14), proportion of metaphase II oocytes (-0.03, -0.58-0.52), fertilization rate (0.15, -0.09-0.38) or embryo quality score (0.05, -0.18-0.29). No OHSS occurred in two of the studies, whereas in one study OHSS incidence was not reported. Thus from the available data, no conclusion can be drawn as regards OHSS incidence after GnRH agonist triggering. In comparison to HCG, GnRH agonist administration is associated with a significantly reduced likelihood of achieving a clinical pregnancy (0.21, 0.05-0.84; P = 0.03). The odds of first trimester pregnancy loss is increased after GnRH agonist triggering; however, the confidence interval crosses unity (11.51, 0.95-138.98; P = 0.05). In conclusion, the use of GnRH agonist to trigger final oocyte maturation in IVF, where inhibition of premature LH surge is achieved with GnRH antagonists, yields a number of oocytes capable to undergo fertilization and subsequent embryonic cleavage, which is comparable to that achieved with HCG. However, the likelihood of an ongoing clinical pregnancy after GnRH agonist triggering is significantly lower as compared to standard HCG treatment.     

Use of microdose GnRH agonist protocol in women with low ovarian volumes undergoing IVF

Ovarian volume measurements have been recently shown to be predictive of response to ovarian stimulation. Women with small ovarian volumes, i.e. <3 cm(3), have a higher incidence of cycle cancellation, together with a lower peak oestradiol concentration, lower number of retrieved oocytes, and lower pregnancy rates, compared with women with larger ovarian volumes. We prospectively investigated whether a higher dose, microdose flare gonadotrophin-releasing hormone (GnRH) agonist protocol, can improve IVF outcome in women with a small ovarian volume. Only the first IVF cycle was reviewed. In total, 109 women aged <40 years undergoing 109 cycles were prospectively evaluated. Women with an ovarian volume of < or =3 cm(3) noted on the day of luteal GnRH agonist administration had their stimulation regimen changed to a more aggressive microdose flare GnRH agonist protocol. In all, 30 women (27.5%) with an ovarian volume of <3 cm(3), and 79 women (72.5%) with an ovarian volume of >3 cm(3) were compared. Women with an ovarian volume of <3 cm(3) had a significantly higher incidence of unexplained infertility as their presenting aetiology, compared with women with a larger ovarian volume (33 and 8.6%, P = 0.0036). There was a significant negative correlation between age and ovarian volume, and between day 3 FSH concentration and ovarian volume. We also report a significant positive correlation between body mass index and ovarian volume. There was also a significant positive correlation between ovarian volume and the number of oocytes retrieved. Despite a trend towards higher day 3 FSH concentrations, a significantly longer duration of stimulation, higher gonadotrophin requirements, and lower oocyte yield, the implantation and pregnancy rates were comparable between the two groups. Women with a small ovarian volume noted at baseline ultrasound can have comparable implantation and pregnancy rates to those with larger ovarian volumes with the use of a higher dose gonadotrophin, microdose GnRH agonist stimulation.     

Cetrorelix in an oral contraceptive-pretreated stimulation cycle compared with buserelin in IVF/ICSI patients treated with r-hFSH: a randomized, multicentre, phase IIIb study

BACKGROUND: The aim of this study was to assess the non-inferiorityof an oral contraceptive (OC)-pretreated cetrorelix regimenand a buserelin regimen in IVF/ICSI patients treated with r-hFSHin terms of total number of oocytes retrieved. METHODS: Multicentre,randomized study. One hundred and eighty two patients were randomizedto receive cetrorelix with OC pretreatment (n = 91) or to receivebuserelin (n = 91). The cetrorelix group started with dailyOCs on cycle day 5 and continued for 21–28 days. Cetrorelix(0.25 mg) was given daily from stimulation day 6 up to and includingthe day of r-hCG administration. The buserelin group startedwith buserelin (500 µg/day) for at least 10 days untildown-regulation was achieved, after which the dose was reducedto daily 200 µg up to and including the day of r-hCG administration.r-hFSH was started in both groups on a Friday, in the cetrorelixgroup 5 days after the last OC pill intake. Both regimens werefollowed by a standard IVF or ICSI procedure. The primary efficacyendpoint was the number of oocytes retrieved per patient. RESULTS:Number of oocytes, cancellation rates, r-hFSH requirements,number of oocyte retrievals during the weekend or public holidayand number of pregnancies were similar in both groups. Bothtreatment regimens were well tolerated. CONCLUSIONS: Cetrorelixpretreated with OCs resulted in similar number of oocytes retrievedcompared with a long buserelin protocol. Both regimens werewell tolerated and allowed scheduling of the oocyte retrieval,with only small number of retrievals falling on a weekend orpublic holiday.     

Use of a single bolus of GnRH agonist triptorelin to trigger ovulation after GnRH antagonist ganirelix treatment in women undergoing ovarian stimulation for assisted reproduction, with special reference to the prevention of ovarian hyperstimulation syndrome: preliminary report: short communication

A new treatment option for patients undergoing ovarian stimulation is the gonadotrophin-releasing hormone (GnRH) antagonist protocol, with the possibility to trigger a mid-cycle LH surge using a single bolus of GnRH agonist, reducing the risk of developing ovarian hyperstimulation syndrome (OHSS) in high responders and the chance of cycle cancellation. This report describes the use of 0.2 mg triptorelin (Decapeptyl) to trigger ovulation in eight patients who underwent controlled ovarian hyperstimulation with recombinant FSH (rFSH, Puregon) and concomitant treatment with the GnRH antagonist ganirelix (Orgalutran) for the prevention of premature LH surges. All patients were considered to have an increased risk for developing OHSS (at least 20 follicles > or =11 mm and/or serum oestradiol at least 3000 pg/ml). On the day of triggering the LH surge, the mean number of follicles > or =11 mm was 25.1 +/- 4.5 and the median serum oestradiol concentration was 3675 (range 2980-7670) pg/ml. After GnRH agonist injection, endogenous serum LH and FSH surges were observed with median peak values of 219 and 19 IU/l respectively, measured 4 h after injection. The mean number of oocytes obtained was 23.4 +/- 15.4, of which 83% were mature (metaphase II). None of the patients developed any signs or symptoms of OHSS. So far, four clinical pregnancies have been achieved from the embryos obtained during these cycles, including the first birth following this approach. It is concluded that GnRH agonist effectively triggers an endogenous LH surge for final oocyte maturation after ganirelix treatment in stimulated cycles. Our preliminary results suggest that this regimen may prove effective in triggering ovulation and could be said to prevent OHSS in high responders. The efficacy and safety of such new treatment regimen needs to be established in comparative randomized studies.     

Human ovarian steroid secretion in vivo: effects of GnRH agonist versus antagonist (cetrorelix).

BACKGROUND: In order to investigate whether gonadotrophin-releasing hormone (GnRH) antagonists exert a significant effect on steroid secretion in vivo compared with GnRH agonists, concentrations of sex steroid hormones (oestradiol, progesterone and testosterone) were studied in follicular fluid from women undergoing ovarian stimulation and treated with either GnRH agonist or antagonist. In addition, the correlation between follicular fluid steroid hormone concentrations and variables of follicular and oocyte development was evaluated. METHODS: Microparticle enzyme immunoassay and radioimmunoassays were used. RESULTS: The mean (SEM) follicular fluid oestradiol concentration was significantly lower in patients treated with GnRH antagonist than in those treated with GnRH agonist (542.0 +/- 76.9 versus 873.0 +/- 105.1 pg/ml, P = 0.02), which correlates with the mean serum oestradiol concentrations found in these two groups. No significant differences were found between groups in follicular fluid progesterone concentrations. Women undergoing GnRH antagonist treatment showed similar concentrations of follicular fluid testosterone compared with GnRH agonist-treated women (14.8 +/- 1.1 versus 13.3 +/- 2.7 ng/ml). The oestradiol:testosterone ratio was markedly reduced in women treated with GnRH antagonist (49.1 +/- 2.3 versus 60.1 +/- 4.4, P = 0.04). In contrast, no differences were found either in the progesterone:testosterone ratio, or in the oestradiol:progesterone ratio. CONCLUSIONS: GnRH antagonist therapy in women undergoing ovarian stimulation had a significant effect on ovarian follicular steroidogenesis.