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.     

Suppression of the endogenous luteinizing hormone surge by the gonadotrophin-releasing hormone antagonist Cetrorelix during ovarian stimulation

Surges of luteinizing hormone (LH) that result In luteinizationbut occur prematurely with respect to the diameter of the leadingfolilde, prevent attempts to induce multiple follicular maturationfor in-vitro fertilization (IVF) in a significant number ofwomen. We examined the possibility of blocking premature LIIsurges by the administration of Cetrorelix, a potent antagonistof gonadotrophin-releasing hormone (GnRH), in a study Including20 patients, some of whom had previously shown premature LHsurges. All patients were treated with human menopausal gonadotrophins(HMG) starting on day 2. From day 7 until the induction of ovulationby human chorionic gonadotrophin (HCG) the GnRII antagon Cetrorelixwas given daily. HCG was injected when the dominant fofficlehad reached a diameter of >18 mm and oestradlol concentrationwas >300 pg/ml for each follicle having a diameter of >15mm. Oocyte collection was performed 36 h later by transvaginalultrasound puncture, followed by IVF and embryo transfer. Thehormone profiles of these patients and the results of IVF andembryo transfer are comparable to those treated with GnRH agonistsand HMG. However, less time and especially less HMG Is neededin comparison to patients stimulated with a long agonist protocol.Hence, treatment with Cetrorelix proved to be much more comfortablefor the patient. In this study we showed that combined treatmentwith gonadotrophins and the GnRH antagonist Cetrorelix is apromising method for ovarian stimulation in patients who frequentlyexhibit premature LH surges and therefore fall to complete treatment.     

Ovarian stimulation for in-vitro fertilization/intracytoplasmic sperm injection with gonadotrophins and gonadotrophin-releasing hormone analogues: agonists and antagonists

The gonadotrophin-releasing hormone (GnRH) antagonists Cetrorelix and Ganirelix have been used in recent years in clinical studies to prove that these compounds reliably prevent the onset of premature luteinizing hormone (LH) surges during ovarian stimulation. Cetrorelix has been applied in single and multiple dose protocols, while Ganirelix has until now only been used in the multiple dose protocol. In the latter protocol, ovarian stimulation is started on day 2 or 3 of the spontaneous cycle with human menopausal gonadotrophin or recombinant follicle stimulating hormone. Daily administration of the GnRH antagonist at its minimum effective dose (0.25 mg/day s.c.) occurs from the sixth day of stimulation onwards until ovulation induction by human chorionic gonadotrophin. In the single dose protocol, 3 mg of the GnRH antagonist Cetrorelix was injected on day 8 of the stimulation cycle. Both protocols have been proven to be safe and effective. Fertilization rates of >60% in in-vitro fertilization and >70% in intracytoplasmic sperm injection, as well as clinical pregnancy rates of approximately 30% per transfer, sound most promising. The incidence of a premature LH surge is below 2%. The incidence of severe ovarian hyperstimulation syndrome seems to be lower under antagonist treatment than in the long agonistic protocol. Treatment time is significantly shortened.     

Induction of ovulation after gnRH antagonists

The gonadotrophin-releasing hormone (GnRH) antagonist binds competitively to the receptors and thereby prevents endogenous GnRH from exerting its stimulatory effect on the pituitary cells. This causes suppression of gonadotrophin secretion which occurs immediately after administration of the antagonist. When using GnRH antagonist in controlled ovarian stimulation, ovulation or maturation of the oocyte can, therefore, be induced by a variety of drugs, e.g. native GnRH, recombinant LH or short-acting GnRH agonists. Short-acting GnRH agonists were recommended for triggering ovulation in cases with a high risk of developing ovarian hyperstimulation syndrome (OHSS). Since it is evident that GnRH is required to initiate the LH surge and the oestradiol rise, a single administration of GnRH antagonist during the late follicular phase delays the LH surge. Studies showed that a single s.c. administration of 3 or 5 mg of Cetrorelix in the late follicular stage was sufficient to prevent the LH surge for 617 days. This phenomenon can be used in high responder patients who are prone to OHSS. The question whether this delay has any effect on oocyte quality and maturation still remains unanswered. Overall, there are four uses for GnRH antagonist: (i) using short-acting GnRH agonists for triggering ovulation in cases in which the GnRH antagonist is part of the protocol for ovarian stimulation. Recombinant LH and native LHRH could also be used as triggers of LH surge; (ii) delaying the LH surge in cases prone to OHSS by treatment with GnRH antagonist; (iii) to administer GnRH antagonist during the luteal phase to decrease the activity of corpora lutea; (iv) in polycystic ovarian disease with elevated LH the LH/FSH ratio can be corrected with the injection of GnRH antagonist prior to and during ovarian stimulation.     

Are endogenous LH levels during ovarian stimulation for IVF using GnRH analogues associated with the probability of ongoing pregnancy? A systematic review

The aim of this systematic review was to evaluate, among women with normal ovulation or World Health Organization (WHO) II oligoanovulation who undergo ovarian stimulation for IVF using GnRH analogues, whether endogenous LH levels predict the likelihood of ongoing pregnancy beyond 12 weeks. A literature search identified six studies that answered the research question, among which two were prospective studies (one in GnRH agonist and one in GnRH antagonist cycles). None of the retrospective studies suggest that low endogenous LH levels are associated with a significantly decreased probability of ongoing pregnancy beyond 12 weeks in such patients. In the two prospective studies high endogenous LH levels during down-regulation were associated with a decreased probability of ongoing pregnancy beyond 12 weeks. Until further prospective studies modify the existing evidence summarized here, an adverse effect of low endogenous LH levels on the probability of ongoing pregnancy beyond 12 weeks is not a sensible rationale for LH supplementation during ovarian stimulation for IVF using GnRH analogues.     

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 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.     

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.     

Use of cetrorelix in combination with clomiphene citrate and gonadotrophins: a suitable approach to 'friendly IVF'?

BACKGROUND: With the recently introduced GnRH antagonists, soft stimulation protocols on the basis of clomiphene pretreatment should be possible as the pituitary remains fully sensitive at the beginning of the cycle. METHODS: A prospective trial was carried out on 107 patients undergoing IVF treatment using the multiple dose GnRH antagonist protocol (cetrorelix), clomiphene citrate, and either HMG (n = 54) or recombinant FSH (rFSH) (n = 53). Different stimulation protocols were used to find the most appropriate one for clinical application. RESULTS: Both treatment groups, HMG and rFSH, yielded comparable results concerning gonadotrophin dose, stimulation days and pregnancy rate. A mean number of 6.34 +/- 4.4 metaphase II oocytes was retrieved and a mean number of 2.45 +/- 0.65 embryos was transferred. However, the overall rate of premature LH surges was 21.5% (defined as measurement of LH >10 IU/l and progesterone >1 ng/ml) which is unacceptable for clinical practice. CONCLUSIONS: Increasing the daily cetrorelix dose from 0.25 to 0.5 mg might decrease the number of premature LH surges. Soft stimulation protocols with clomiphene should be used cautiously.     

The use of a GnRH antagonist (Cetrorelix) in a single dose protocol in IVF-embryo transfer: a dose finding study of 3 versus 2 mg

New gonadotrophin-releasing hormone (GnRH) antagonists, which allow suppression of luteinizing hormone (LH) surges, have recently become available. We compared in this study the results of a single administration of 3 versus 2 mg Cetrorelix in 65 patients undergoing ovarian stimulation and in-vitro fertilization (IVF). The GnRH antagonist (Cetrorelix) was non-randomly administered at a dose of 3 mg (34 patients) or 2 mg (32 patients) on day 8 of the stimulation cycle. In the case of slow follicular development, the injection was delayed until oestradiol reached 400 pg/ml. No difference was observed in the decrease in LH and in oestradiol secretion between the 3 and the 2 mg groups, but the LH secretion was suppressed for a shorter time in the 2 mg group. No LH surge was observed in the 3 mg group, while one surge (3%) and one significant rise in LH were observed in the 2 mg group. No significant difference was observed in IVF results in the two groups of patients. This study demonstrates that a single injection of 3 or 2 mg successfully prevents LH surges for at least 3 days in all the patients treated. The LH rises in the 2 mg group led us to choose the 3 mg dose as a safer dose in our single administration protocol.      

Revival of the natural cycles in in-vitro fertilization with the use of a new gonadotrophin-releasing hormone antagonist (Cetrorelix): a pilot study with minimal stimulation

Natural cycles were abandoned in in-vitro fertilization (IVF) embryo transfer, due to premature luteinizing hormone (LH) surges--and subsequent high cancellation rates. In this study, we investigated the administration of a new gonadotrophin-releasing hormone antagonist (Cetrorelix) in the late follicular phase of natural cycles in patients undergoing IVF and intracytoplasmic sperm injection (ICSI). A total of 44 cycles from 33 healthy women [mean age 34.1 +/- 1.4 (range 26-36) years] were monitored, starting on day 8 by daily ultrasound and measurement of serum concentrations of oestradiol, LH, follicle stimulating hormone (FSH) and progesterone. When plasma oestradiol concentrations reached 100-150 pg/ml, with a lead follicle between 12-14 mm diameter, a single injection (s.c.) of 0.5 mg (19 cycles) or 1 mg (25 cycles) Cetrorelix was administered. Human menopausal gonadotrophin (HMG; 150 IU) was administered daily at the time of the first injection of Cetrorelix, and repeated thereafter until human chorionic gonadotrophin (HCG) administration. Four out of 44 cycles were cancelled (9.0%). No decline in follicular growth or oestradiol secretion was observed after Cetrorelix administration. A total of 40 oocyte retrievals leading to 22 transfers (55%) was performed. In 10 cycles (25%), no oocyte was obtained. Fertilization failure despite ICSI occurred in six cycles (15%). In two patients the embryo was arrested at the 2 pronuclear (PN) stage. The stimulation was minimal (4.7 +/- 1.4 HMG ampoules). A total of seven clinical pregnancies was obtained (32.0% per transfer, 17.5% per retrieval), of which five are ongoing. Thus, a spontaneous cycle and the GnRH antagonist Cetrorelix in single dose administration could represent a first-choice IVF treatment with none of the complications and risks of current controlled ovarian hyperstimulation protocols, and an acceptable success rate.     

Minimal stimulation IVF with late follicular phase administration of the GnRH antagonist cetrorelix and concomitant substitution with recombinant FSH: a pilot study

BACKGROUND: The use of the natural cycle for IVF offers the advantage of a patient-friendly and low-risk protocol. Its effectiveness is limited, but may be improved by using a GnRH antagonist to prevent untimely LH surges. METHODS: In this pilot study, minimal stimulation IVF with late follicular phase administration of the GnRH antagonist cetrorelix and simultaneous substitution with recombinant FSH was applied for a maximum of three cycles per patient. Main outcome measures were pregnancy rates per started cycle and cumulative pregnancy rates after three cycles. RESULTS: A total of 50 patients completed 119 cycles (2.4 per patient). Fifty-two embryo transfers resulted in 17 ongoing pregnancies [14.3% per started cycle; 32.7% per embryo transfer; 95% confidence interval (CI) 7.9-20.7% and 19.7-45.7%, respectively]. One dizygotic twin pregnancy occurred after transfer of two embryos, the other pregnancies were singletons. The cumulative ongoing pregnancy rate after three cycles was 34% (95% CI 20.6-47.4%). Live birth rate was 32% per patient (95% CI 18.8-45.2%). CONCLUSIONS: Pregnancy rates after IVF with minimal, late follicular phase stimulation are encouraging. Considering the low-risk and patient-friendly nature of this protocol, it may be a feasible alternative to IVF with ovarian hyperstimulation.     

Efficacy of nafarelin in assisted reproductive technology: a meta-analysis

A systematic review identified nine randomized, controlled trials (both published and unpublished) which assessed the efficacy of nafarelin during IVF compared with other gonadotrophin-releasing hormone (GnRH) agonists. The trials included 1,014 women (nafarelin n = 597) in protocols employing three different dosage regimens, long and short stimulation protocols, and three comparative GnRH agonists (buserelin n = 348; triptorelin n = 14, and leuprolide n = 55). The meta-analysis of the data showed that pregnancy rates per embryo transfer with nafarelin were equivalent to those obtained with other GnRH agonists. Nafarelin and other agonists were also comparable in terms of several intermediate IVF outcomes, including fertilization rates, number of oocytes retrieved, peak oestradiol concentrations, and cycle cancellations. Women treated with nafarelin required fewer ampoules of human menopausal gonadotrophin (HMG)/FSH for ovarian stimulation and fewer days of stimulation. Safety results from both the meta-analysis and a qualitative analysis of 12 additional reports suggested that adverse effects were within the accepted tolerance range; the most frequent adverse effects were hypo-oestrogenic symptoms. In conclusion, the overall efficacy of nafarelin was equivalent to that of other GnRH agonists. The possibility that the reduced gonadotrophin requirements in women taking nafarelin will translate into cost savings per IVF treatment cycle requires further study.     

Efficacy of natural cycle IVF: a review of the literature

Since the introduction of IVF treatments, natural cycle IVF has been largely replaced by IVF with ovarian stimulation. However, natural cycle IVF has several advantages. It is associated with a close to zero multiple pregnancy rate, and a zero risk of ovarian hyperstimulation syndrome. Per cycle, natural cycle IVF is less time consuming, physically and emotionally less demanding for patients, and cheaper than stimulated IVF, but also less effective. This systematic literature review addresses the issue of effectiveness of natural cycle IVF. Herein, 20 studies describing natural cycle IVF are presented; 12 case series and eight in which a comparison was made between natural cycle IVF and IVF with ovarian stimulation. Good-quality randomized controlled trials and formal cost-effectiveness analyses are lacking. The 20 selected studies comprised a total of 1800 cycles of natural cycle IVF, resulting in 819 embryo transfers (45.5% per cycle) and 129 ongoing pregnancies (7.2% per cycle and 15.8% per embryo transfer). Efficacy of natural cycle IVF is hampered by high cancellation rates because of premature LH rise and premature ovulations. It is concluded that natural cycle IVF is a low-risk, low-cost and patient-friendly procedure. A randomized controlled trial comparing natural cycle IVF with current standard treatment strategies is warranted.     

Among patients treated with FSH and GnRH analogues for in vitro fertilization, is the addition of recombinant LH associated with the probability of live birth? A systematic review and meta-analysis

The aim of this systematic review and meta-analysis was to assess whether the addition of recombinant luteinizing hormone (LH) increases live birth rate, among patients treated with follicle stimulating hormone (FSH) and gonadotrophin-releasing hormone (GnRH) analogues for in vitro fertilization (IVF). Eligible studies were randomized controlled trials (RCTs) answering the research question that contained sufficient information to allow ascertainment of whether randomization was true and whether equality was present between the groups compared, regarding baseline demographic characteristics, gonadotrophin stimulation protocol, number of embryos transferred and luteal phase support administered. A literature search identified seven RCTs (701 patients) that provided the information of interest, among which five reported agonist and two antagonist cycles. The reported outcome measure, clinical pregnancy, was converted to live birth using published data in one study. No significant difference in the probability of live birth was present with or without rLH addition to FSH (odds ratio [OR]: 0.92, 95% confidence interval (CI): 0.65-1.31; P = 0.65). This finding remained stable in subgroup analyses that ordered the studies by dose of rLH added, the type of analogue used to inhibit premature LH surge, the time rLH was added during the follicular phase, the age of patients analysed, the presence of allocation concealment and by the way the information on live birth was retrieved. In conclusion, the available evidence does not support the hypothesis that the addition of recombinant LH increases the live birth rate in patients treated with FSH and GnRH analogues for IVF.     

Regulation of follicle development and novel approaches to ovarian stimulation for IVF

Current ovarian stimulation regimens for IVF are complex and not without risk. Increasing our knowledge of the physiology of follicle development and dominant follicle selection may enable the design of less complex, safer and cheaper ovarian stimulation regimens for IVF. Decremental serum FSH concentrations during the follicular phase of the menstrual cycle are required for single dominant follicle selection. Only the most mature follicle will continue its development due to increased sensitivity for stimulation by FSH. FSH stimulation becomes insufficient for less mature follicles and remaining cohort follicles will therefore go into atresia. The number of days during which FSH is above the threshold for stimulation of follicle development is limited, resulting in a narrow FSH window. More medium sized and large pre-ovulatory follicles and increased oestradiol output can be induced by the administration of small doses of exogenous FSH during the mid- to late follicular phase, preventing the physiological decrease in FSH stimulation. Intervention with decremental serum FSH concentrations in combination with gonadotrophin-releasing hormone (GnRH) antagonists to prevent a premature rise in serum LH may induce ongoing growth of multiple follicles sufficient for IVF. The benefits and risks of these minimal hyperstimulation protocols require further evaluation.     

An update of luteal phase support in stimulated IVF cycles

Stimulated IVF cycles are associated with luteal phase defect. In order to overcome this, different doses, durations and types of luteal phase support (LPS) have been evaluated. There is still no agreement regarding the optimal supplementation scheme. The aim of this paper is to assess the past and the current clinical practices of luteal supplementation in IVF. The databases of Medline and PubMed were searched to identify relevant publications. LPS with human chorionic gonadotrophin (hCG) [n=262, odds ratio (OR) 2.72 (95%), confidence interval (CI) 1.56-4.90, P<0.05] or progesterone (n=260, OR 1.57 CI 1.13, 2.17, P<0.05) results in an increased pregnancy rate compared with placebo, however, hCG is associated with increased risk of ovarian hyperstimulation syndrome. Natural micronized progesterone is not efficient if taken orally. The data on oral dydrogesterone are still conflicting. Vaginal and intra muscular progesterone have comparable outcomes. The addition of estradiol (E2) seems to be beneficial in long GnRH agonist protocol (implantation rate 39.6% with E2 compared with no E2; P<0.05) but not in the short GnRH agonist and GnRH antagonist protocol. Despite the early promising results, it is too early to recommend the use of GnRH agonist in LPS. LPS should cease on the day of positive HCG. Since the cause of luteal phase defect in IVF appears to be related to the supraphysiological levels of steroids, milder stimulation protocols should be advocated in order to eventually overcome the luteal phase defect.     

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.