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.     

The use of GnRH antagonists in ovarian stimulation

GnRH antagonists induce a rapid decrease in LH and FSH, preventing and interrupting LH surges. Their properties do not require a desensitization period, and this allows their use in the late follicular phase. GnRH antagonists could replace GnRH agonists in controlled ovarian stimulation without their side-effects and their long desensitization period. Two protocols for assisted reproduction technology (ART) cycles were designed: the single-dose protocol allies simplicity and efficacy, while the multiple-dose protocol is efficient and could reduce monitoring of the cycle, though compliance is mandatory. A review of the available literature on GnRH antagonists in ART cycles is presented, focusing on phase III controlled trials and ART results. Both protocols using GnRH antagonists were associated with the need for a smaller dose of gonadotrophin, a shorter stimulation period and a lower incidence of ovarian hyperstimulation syndrome (OHSS), albeit with statistically comparable pregnancy rates. A trend is observed in all studies showing a lower pregnancy rates in GnRH antagonist cycles as compared with GnRH agonist cycles. The role of the lower number of embryos, and the potential adverse effects of GnRH antagonists on endometrium or follicle must be studied. More cycles using GnRH antagonists are necessary to confirm their equivalent pregnancy rates. There is room for improvement in both protocols with regard to scheduling, antagonist dose level and the timing of its administration. Until further studies have been conducted, luteal support seems to remain mandatory. Perinatal outcome appears similar to that with other stimulation regimens. Triggering of ovulation can be obtained with GnRH agonist for patients at risk of OHSS. With regard to GnRH antagonists, questions remain regarding pregnancy rates, the indications of their use in patients with polycystic ovary syndrome or poor responders, and in ovarian stimulation outside IVF.     

GnRH antagonists in ovarian stimulation for IVF

The present review describes, on the basis of the currently available evidence, the consensus reached by a group of experts on the use of gonadotropin-releasing hormone (GnRH) antagonists in ovarian stimulation for IVF. The single or multiple low-dose administration of GnRH antagonist during the late-follicular phase effectively prevents a premature rise in serum luteinizing hormone (LH) levels in most women. Although controversy remains, most comparative studies suggest a slight, not significant reduction in the probability of pregnancy after IVF using GnRH antagonist versus GnRH agonist co-treatment. Published meta-analyses suggest that this slight difference in pregnancy rates is not attributed to chance. Further studies applying varying treatment regimens and outcome measures are required. Data are not in favour of a need to modify the starting dose of gonadotropins. Data are not in favour of increasing gonadotropin dose at GnRH antagonist initiation. The addition of LH from the initiation of ovarian stimulation or from GnRH antagonist administration does not appear to be necessary. Replacement of human chorionic gonadotropin (HCG) by GnRH agonist for triggering final oocyte maturation is associated with a lower probability of pregnancy. The optimal timing for HCG administration needs to be explored further. GnRH antagonist initiation on day 6 of stimulation appears to be superior to flexible initiation by a follicle of 14-16 mm, although earlier GnRH antagonist administration is worth further evaluation. Luteal phase supplementation in GnRH antagonist protocols remains mandatory in IVF. Effects of GnRH antagonist co-treatment on the incidence of ovarian hyperstimulation syndrome remains uncertain, although a trend is present in favour of the GnRH antagonists. The role of GnRH antagonists in ovarian stimulation for IVF appears to be promising, although many questions regarding preferred dose regimens and effects on clinical outcomes remain.     

The LHRH antagonist cetrorelix: a review

In those clinical situations in which an immediate and profound suppression of gonadotrophins is desired, LHRH agonists have the disadvantage of producing an initial stimulatory effect on hormone secretion. Therefore, the use of GnRH antagonists which cause an immediate and dose-related inhibition of LH and FSH by competitive blockade of the receptors is much more advantageous. One of the most advanced antagonist produced to date is Cetrorelix, a decapeptide which has been shown to be safe and effective in inhibiting LH and sex-steroid secretion in a variety of animal species and in clinical studies as well. Clinical trials in patients suffering from advanced carcinoma of the prostate, benign prostate hyperplasia, and ovarian cancer are currently in progress and have already shown the usefulness of this new treatment modality. In particular, the concept that a complete suppression of sex-steroids may not be necessary in indications such as uterine fibroma, endometriosis and benign prostatic hyperplasia represents a promising novel perspective for treatment of these diseases. Following completion of phase III trials in controlled ovarian stimulation for IVF regimens, Cetrorelix was given marketing approval and, thus, became the first LHRH antagonist available clinically.     

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.     

EndocrinologyHormonal profile during the follicular phase in cycles stimulated with a combination of human menopausal gonadotrophin and gonadotrophin-releasing hormone antagonist (Cetrorelix)

A third-generation gonadotrophin-releasing hormone antagonist(Cetrorelix) was used during ovarian stimulation in 32 patientsundergoing assisted reproduction, in order to prevent the prematureluteinizing hormone (LH) surge. In all patients, ovarian stimulationwas carried out with two or three ampoules of human menopausalgonadotrophin (HMG), starting on day 2 of the menstrual cycle.In addition, 0.5 mg of Cetrorelix was administered daily fromday 6 of HMG treatment until the day of ovulation inductionby human chorionic gonadotrophin (HCG). A significant drop inplasma LH concentration was observed within a few hours of thefirst administration of Cetrorelix (P<0.005). Moreover, noLH surge was detected at any point in the treatment period inany of the 32 patients. A mean oestradiol concentration of 2122±935ng/1 was observed on the day of the HCG administration, indicatingnormal folliculogenesis. Like LH, progesterone concentrationalso dropped within a few hours of the first administrationof Cetrorelix (P< 0.005). A 0.5 mg daily dose of Cetrorelixprevented a premature LH surge in all the 32 patients treated.     

Direct ovarian effects and safety aspects of GnRH agonists and antagonists

In in-vitro fertilization programmes, gonadotrophin releasing hormone (GnRH) agonists are now routinely used in order to prevent the undesired pre-ovulatory spontaneous luteinizing hormone surge. The first publications are now appearing in which GnRH antagonists are used with the same purpose. More attention should be addressed to the safety aspects of these drugs. This review aims to summarize studies on direct ovarian effects of GnRH agonists and GnRH antagonists in non-primates and primates with respect to the functional and morphological aspects in-vitro as well as in-vivo. We conclude that there is a wide variety of functional and morphological effects of GnRH analogues on the ovary. The sometimes paradoxical effects indicate that a variety of factors may be involved in the various processes. Those factors are: (i) the type and dose of the analogue, (ii) the different regimens of administration, (iii) ovarian status at the time of exposure, (iv) ovarian cell types in in-vitro systems, (v) hormonal pre-treatment of these cultures, (vi) the type of hormonal stimulation added to the in-vitro culture, (vii) further methodological differences in the experiments and finally (viii) physiological variations in GnRH receptor abundance which depends on species and/or timing in the cycle. With the increasing number of patients using GnRH analogues in assisted reproduction treatments, there will be an increasing number of pregnancies exposed to these drugs. So far, there does not appear to be an increased risk of birth defects or pregnancy wastage in human pregnancies exposed to daily low-dose GnRH agonist therapy in the first weeks of gestation.     

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.     

Androgen priming using aromatase inhibitor and hCG during early-follicular-phase GnRH antagonist down-regulation in modified antagonist protocols

BACKGROUND: Temporary exposure of follicles to increased levels of androgens may enhance their sensitivity to FSH. The aim of this study was to increase the intraovarian androgen level using aromatase inhibitors and hCG before controlled ovarian stimulation (COH) and to test this concept clinically. METHODS: In a prospective, non-randomized study, 45 patients were treated in modified antagonist protocols including early-follicular-phase down-regulation and androgen priming before COH. All patients received cetrorelix, 3 mg s.c., on cycle days 2 and 5. Group I (n=15) received no other pretreatment. Group II (n=15) received 1 daily tablet of aromatase inhibitor, letrozole 2.5 mg, from cycle days 2 to 8. Group III (n=15) received letrozole as Group II and 1250 IU of hCG s.c. on cycle day 2. From cycle day 8, all patients were stimulated with highly purified menotrophin in a flexible antagonist protocol. RESULTS: Aromatase inhibitor increased the level of testosterone in follicular fluid (P<0.002), but not in plasma. Androgen priming with aromatase inhibitor and hCG increased the number of good-quality embryos (P=0.015) but did not increase the implantation rate. CONCLUSIONS: The use of aromatase inhibitor before COH significantly influences the local endocrine environment before and during stimulation. Androgen priming with both aromatase inhibitor and hCG may result in more good-quality embryos.     

Recombinant human LH supplementation during GnRH antagonist administration in IVF/ICSI cycles: a prospective randomized study

BACKGROUND: When administered in the late follicular phase to prevent an LH surge, GnRH antagonists induce a sharp decrease in serum LH levels that may be detrimental for assisted reproductive technology cycle outcome. Therefore, a prospective study was designed to assess the effects of recombinant human (r)LH supplementation during GnRH antagonist (cetrorelix) administration. METHODS: The protocol consisted of cycle programming with oral contraceptive pill, ovarian stimulation with rFSH and flexible administration of a single dose of cetrorelix (3 mg). A total of 218 patients from three IVF centres were randomized (by sealed envelopes or according to woman's birth date) to receive (n = 114) or not (n = 104) a daily injection of rLH 75 IU from GnRH antagonist initiation to hCG injection. RESULTS: The only significant difference was a higher serum peak E2 level in patients treated with rLH (1476 +/- 787 versus 1012 +/- 659 pg/ml, P < 0.001) whereas the numbers of oocytes and embryos as well as the delivery rate (25.2 versus 24%) and the implantation rate per embryo (19.1 versus 17.4%) were similar in both groups. CONCLUSIONS: These results show that in an unselected group of patients, there is no evident benefit to supplement GnRH antagonist-treated cycles with rLH.     

Comparable clinical outcome using the GnRH antagonist ganirelix or a long protocol of the GnRH agonist triptorelin for the prevention of premature LH surges in women undergoing ovarian stimulation

This multicentre, randomized study was performed to assess theefficacy and safety of 0.25 mg ganirelix (Orgalutran^®, Antagon^TM)treatment, using triptorelin (Decapeptyl^®) in a long protocolas a reference treatment. In total, 236 subjects were randomizedto treatment with ganirelix (0.25 mg, s.c.) and 119 to triptorelin(0.1 mg, s.c.) treatment (treatment ratio 2:1). Treatment withganirelix started on day 6 of stimulation, whereas treatmentwith triptorelin started on menstrual cycle day 21 to 24 ofthe previous cycle (i.e. the midluteal phase). The ganirelixregimen was on average 17 days shorter (9 versus 26 days) comparedto the triptorelin regimen. The median total dose of recombinantFSH (Puregon^®) used was 450 IU less (1350 versus 1800 IU)in the ganirelix protocol. The initial follicular growth wasfaster and, consequently, oestradiol concentrations were higherin the ganirelix group. On the day of human chorionic gonadotrophin(HCG), the mean number of follicles 11 mm was 10.1 and 10.7and the median serum oestradiol concentration was 1090 and 1370pg/ml in the ganirelix and triptorelin groups respectively.Per attempt, 7.9 and 9.6 oocytes (mean) were retrieved in theganirelix and triptorelin groups respectively. The fertilizationrates (64.0% ganirelix and 64.9% triptorelin) and the mean numberof good quality embryos (2.7 and 2.9) were comparable in bothtreatment groups. The implantation rate was identical (22.9%).The ongoing pregnancy rate per attempt was 31.0 and 33.9% inthe ganirelix and triptorelin groups respectively. The ganirelixregimen showed an improved local tolerance in that the percentageof subjects with at least one local skin reaction was 2-foldlower than in the triptorelin group (11.9 versus 24.1%). Takingall data together, it may be concluded that ganirelix offersa new treatment regimen in ovarian stimulation that is short,safe and well-tolerated, optimizing convenience for the patient.     

In a flexible antagonist protocol, earlier, criteria-based initiation of GnRH antagonist is associated with increased pregnancy rates in IVF

BACKGROUND: The purpose of the study was to assess ongoing pregnancy rates across groups of patients treated by IVF, which were defined according to criteria aimed at the prevention of premature LH surge and used for initiating GnRH antagonist. METHODS: This is a prospective observational cohort study. During the last 3 years, in IVF-ICSI patients undergoing controlled ovarian stimulation (COS) with the antagonist protocol, the antagonist administration was initiated according to at least one of the following patient-specific criteria: (i) at least one follicle measuring >14 mm; (ii) estradiol levels >600 pg/ml; and (iii) LH levels >10 IU/l. Based upon these criteria, 208 cases of normal responders were analysed and categorized into three groups according to the starting day of the regimen: group D4 (n = 40) for day 4, group D5 (n = 98) for day 5 and group D6 (n = 70) for day 6. The main outcome measure was the ongoing pregnancy rate per started cycle. RESULTS: The total number of patients in the D4 and D5 groups (138 out of 208), who received the antagonist earlier, was considerably larger compared with that of D6 (70 out of 208). Ongoing pregnancy rates were 37.5, 34.7 and 18.6% for groups D4, D5 and D6, respectively. Patients who initiated the GnRH antagonist on days 4 and 5 had statistically significant higher pregnancy rates compared with day 6. Rapid response, causing earlier antagonist administration initiation, according to the proposed criteria for the prevention of premature LH surges, and the absence of premature luteinization, as evidenced by normal progesterone levels on HCG day, were found to be independent positive predictive factors for favourable IVF outcome. CONCLUSIONS: The employment of an algorithm of criteria, aimed at the prevention of premature LH surges in a flexible antagonist protocol, resulted in antagonist initiation earlier than on stimulation day 6 in a significant proportion of patients. In those patients, a higher pregnancy rate was observed.     

The GnRH antagonist cetrorelix reduces cyclophosphamide-induced ovarian follicular destruction in mice

BACKGROUND: It has remained controversial whether and in what way suppression of the pituitary-gonadal axis using GnRH analogues can reduce the destructive effects of chemotherapy on ovarian primordial follicles and thus prevent ovarian failure. GnRH antagonists suppress gonadotrophin levels immediately after administration. In this study we determined whether administration of the GnRH antagonist cetrorelix before exposure to increasing doses of cyclophosphamide (Cy) affected the number of surviving primordial follicles (PMF) in the mice ovary. METHODS: Highly inbred young Balb/c mice (114 females) were injected with 0, 50 and 75 mg/kg of Cy. In each treatment group, half of the females were injected daily with cetrorelix starting 9 days before and 7 days post-administration of Cy. In serial sequential ovarian sections the total number of PMF in both ovaries was counted. RESULTS: Ovaries exposed to Cy at doses of 50 and 75 mg/kg had significantly fewer PMF than those in the control group (P < 0.01). In each of the Cy groups used, pretreatment with cetrorelix resulted in significantly higher numbers of PMF: in the 50 mg/kg Cy group only 14% were destroyed (cetrorelix group) versus 53% (P < 0.001), while in the 75 mg/kg Cy group only 35% of PMF were destroyed versus 54% in animals treated only with Cy (P < 0.004). The interaction between the effect of cetrorelix and the different doses of Cy did not reach statistical significance (P = 0.089, two-way ANOVA). CONCLUSIONS: Administration of the GnRH antagonist cetrorelix to mice significantly decreases the extent of ovarian damage induced by the chemotherapeutic agent Cy. The use of different substerilizing doses of Cy suggested that the extent of protection achieved by the antagonist is dose-dependent and decreases with increasing Cy doses. The results of this study may suggest a possible similar beneficial effect in women undergoing chemotherapy, can explain the discrepancy in results of existing clinical studies and indicate possible pathways for ovarian GnRH agonist protection. Further research and clinical studies are needed in order to confirm these results.     

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.     

Endocrinology: Subtle progesterone rise after the administration of the gonadotrophin-releasing hormone antagonist Cetrorelix in intracytoplasmic sperm injection cycles

In the present study, subtle serum progesterone rise (1.1 ng/ml)during the late follicular phase is reported, for the firsttime to our knowledge, in patients using a potent gonadotrophin-releasinghormone (GnRR) antagonist, Cetrorelix, in combination with humanmenopausal gonadotrophin (HMG) for ovarian stimulation priorto intracytoplasmic sperm injection (ICSI). In five out of 24patients (20%) serum progesterone levels were1.1 ng/ml. Thecycle characteristics of the patients were similar in both groups.No premature endogenous luteimzing hor mone (LH) surge occurredand the serum LH concentrations were constantly low during thefollicular phase. The l7- oestradiol and follicle stimulatinghormone (FSH) exposure were higher in cycles with prematureluteinization. The greater oestradiol and FSH exposure confirmthat one of the possible factors inducing subtle serum progesteronerise is the increased oestradiol and FSH induced LH receptivityin granulosa cells.     

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.     

Ovarian stimulation with GnRH agonist, but not GnRH antagonist, partially restores the expression of endometrial integrin beta3 and leukaemia-inhibitory factor and improves uterine receptivity in mice

BACKGROUND: The impact of different ovarian stimulation (OS) protocols on endometrial receptivity remains controversial. In this study, the effects of different OS on the expression of endometrial integrin beta3 subunit and leukaemia-inhibitory factor (LIF) during the implantation window and the implantation rate in mice were investigated. METHODS: Three OS protocols were used, involving either pregnant mare's serum gonadotrophin (PMSG) alone, PMSG plus GnRH agonist or PMSG plus GnRH antagonist. Uterus samples were collected at 48 h after OS or ovulation and were detected with immunohistochemistry, Western blot and RT-PCR analyses. Normal embryos at gestation day 4 were transferred into the uteri of mice in the control and OS groups. RESULTS: All OS groups showed a significant decrease in the expression of both the endometrial integrin beta3 subunit and LIF during the implantation window and the implantation rate. Among the three OS groups, GnRH agonist-treated mice showed a higher endometrial integrin beta3 subunit and LIF expression and a higher implantation rate. No significant difference was found in the measured indices between the GnRH antagonist and PMSG groups. CONCLUSIONS: OS may inhibit the expression of endometrial integrin beta3 subunit and LIF and impair endometrial receptivity in mice. OS with GnRH agonist, but not GnRH antagonist, may partially restore the endometrial physiological secretion and improve uterine receptivity.     

The effect of GnRH analogues for pituitary suppression on ovarian response in repeated ovarian stimulation cycles

Introduction

Ovarian stimulation is employed in assisted reproduction techniques in order to obtain as many oocytes as possible. The early rise in oestradiol levels may lead to the premature end of the respective cycle. In order to avoid such an effect, pituitary suppression has been employed. The aim of this study was to evaluate whether maintenance or replacement of the type of GnRH analogue (i.e., agonist or antagonist) employed for pituitary suppression in the consecutive intracytoplasmic sperm injection (ICSI) cycle would negatively influence oocyte quality and ICSI outcome.

Material and methods

A retrospective observational study was conducted including 181 women with primary infertility. Patients were divided into four different groups according to the GnRH analogue used for pituitary suppression in the first and consecutive cycle.

Results

When a GnRH agonist was employed for pituitary suppression in the first cycle, the consecutive cycle showed comparable outcomes when performed with either a GnRH agonist or a GnRH antagonist. When the first cycle was performed with a GnRH antagonist, the use of the GnRH agonist in the successive cycle led to an increased number of oocytes retrieved (7.5% vs. 10.3%, p = 0.032) and the production of a higher number of embryos (4.5% vs. 6.3%, p = 0.036).

Conclusions

When the first cycle is carried out with a GnRH antagonist, the use of a GnRH agonist in the successive cycle would lead to increased numbers of oocytes collected and embryos produced.