Pituitary and ovarian suppression after early follicular and mid-luteal administration of a LHRH agonist in a depot formulation: decapeptyl CR

The optimal timing of frozen-thawed embryo transfer: delayed or not delayed? A systematic review and meta-analysis

Background

The use of frozen embryo transfer (FET) has grown exponentially over the past few years. However, in clinical practice, there are no specific criteria as to whether a delay of at least one menstrual cycle is required for an FET after a failed fresh ET or a freeze-all cycle.

Objective

Through the effects on live birth rate (LBR), clinical pregnancy rate (CPR) and pregnancy loss rate (PLR), to determine whether FET requires a delay of at least one menstrual cycle after fresh ET failure or a freeze-all cycle.

Methods

The search was conducted through PubMed, Web of Science, CNKI, and Wanfang databases for terms related to FET timing as of April 2023. There are no restrictions on the year of publication or follow-up time. Women aged 20 to 46 with any indication for in vitro fertilization and embryo transfer (IVF-ET) treatment are eligible for inclusion. Oocyte donation studies are excluded. Except for the case report, study protocol, and abstract, all original studies are included.

Results

In 4,124 search results, 19 studies were included in the review. The meta-analysis includes studies on the adjusted odds ratio (OR) and 95% confidence interval (CI) of reported live birth rate (LBR), clinical pregnancy rate (CPR), and pregnancy loss rate (PLR), 17 studies were retrospective cohort study, and 2 studies were randomized controlled trial, a total of 6,917 immediate FET cycles and 16,105 delayed FET cycles were involved. In this meta-analysis, the combined OR of LBR was [OR = 1.09, 95% CI (0.93–1.28)], the combined OR of CPR was [OR = 1.05, 95% CI (0.92–1.20)], and the combined OR of PLR was (OR = 0.96, 95% CI 0.75–1.22). There was no statistical significance between the two groups.

Conclusion

Overall, delaying FET by at least one menstrual cycle has no advantage in LBR, CPR, or PLR. So, flexible scheduling of FETs is available to both doctors and patients.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42020161648.

Recombinant-luteinzing hormone supplementation in women during IVF/ICSI cycles with GNRH-antagonist protocol: A systematic review and meta-analysis

The objective of this meta-analysis is to determine the beneficial effect of recombinant-luteinizing Hormone (r-LH) addition in women undergoing in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) with gonadotropin-releasing hormone (GnRH) antagonist protocol and whether an optimal time of Recombinant-Luteinizing Hormone (r-LH) supplementation exist during the controlled of stimulation (COS). The primary outcomes are clinical Pregnancy rate and the number of oocytes retrieved. Secondary outcomes are the number of metaphase II oocytes, miscarriage rate and live birth rate. Results show that supplementation of LH generated a greater number of oocytes retrieved than patients who did not receive LH supplementation, but it did not help with other pregnancy outcomes. Furthermore, the result of the subgroup analysis revealed no significant difference in the outcomes with different LH addition times.

The follicular-phase depot GnRH agonist protocol results in a higher live birth rate without discernible differences in luteal function and child health versus the daily mid-luteal GnRH agonist protocol: a single-centre, retrospective, propensity score matched cohort study

BACKGROUND

The gonadotropin-releasing hormone agonist (GnRH-a) has been used in in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles for a long time. This paper evaluates the efficacy and safety of two commonly used protocols (follicular-phase depot GnRH-a protocol and daily mid-luteal long GnRH-a protocol) in normal responders undergoing IVF/ICSI using propensity score matching (PSM) analysis.

METHODS

A total of 6,816 infertile women treated within the period from January 2016 to September 2020 were stratified into cohorts. A total of 2,851 patients received the long-acting group (depot GnRH-a protocol), and 1,193 used the short-acting group (long GnRH-a protocol) after the data-selection process. PSM was utilized for sampling by up to 1:1 nearest neighbour matching to adjust the numerical difference and balance the confounders between groups. The primary outcome was the live birth rate (LBR). Multivariable logistic analysis was used to evaluate the difference between these two protocols in relation to the LBR.

RESULT(S)

In this study, 1:1 propensity score matching was performed to create a perfect match of 964 patients in each group. After matching, the blastocyst formation rates, oestradiol (E₂) value on Day hCG + 9, progesterone (P) value on Day hCG + 9, implantation rates, clinical pregnancy rates, and LBR were more favourable in the depot GnRH-a protocol than in the long GnRH-a protocol (P < 0.05). However, the moderate or severe OHSS rates were higher in the depot group than in the long group (P < 0.001). There were no significant differences in endometrial thickness, luteal support medication, early pregnancy loss rates, mid- and late-term pregnancy loss rates, or foetal malformation rates between the two protocols.

CONCLUSION(S)

Compared with the daily short-acting GnRH agonist protocol, the follicular-phase depot GnRH-a protocol might improve LBRs in normogonadotropic women without discernible differences in luteal function and child health.

Effect of recombinant LH supplementation timing on clinical pregnancy outcome in long-acting GnRHa downregulated cycles

Background

Timely and moderate luteinizing hormone (LH) supplementation plays positive roles in in vitro fertilization/intracytoplasmic sperm injection and embryo transfer (IVF/ICSI-ET) cycles with long-acting gonadotropin-releasing hormone agonist (GnRHa) pituitary downregulation. However, the appropriate timing of LH supplementation remains unclear.

Methods

We carried out a retrospective cohort study of 2226 cycles at our reproductive medicine centre from 2018 to 2020. We mainly conducted smooth curve fitting to analyse the relationship between the dominant follicle diameter when recombinant LH (rLH) was added and the clinical pregnancy outcomes (clinical pregnancy rate or early miscarriage rate). In addition, total cycles were divided into groups according to different LH levels after GnRHa and dominant follicle diameters for further analysis.

Results

Smooth curve fitting showed that with the increase in the dominant follicle diameter when rLH was added, the clinical pregnancy rate gradually increased, and the early  miscarriage rate gradually decreased.

Conclusions

In long-acting GnRHa downregulated IVF/ICSI-ET cycles, the appropriate timing of rLH supplementation has a beneficial impact on the clinical pregnancy outcome. Delaying rLH addition is conducive to the clinical pregnancy rate and reduces the risk of early miscarriage.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04963-x.

Is it necessary to monitor the serum luteinizing hormone (LH) concentration on the human chorionic gonadotropin (HCG) day among young women during the follicular-phase long protocol? A retrospective cohort study

BACKGROUND

The normal physiological function of LH requires a certain concentration range, but because of pituitary desensitization, even on the day of HCG, endogenous levels of LH are low in the follicular-phase long protocol. Therefore, our study aimed to determine whether it is necessary to monitor serum LH concentrations on the day of HCG (LH_HCG) and to determine whether there is an optimal LH_HCG range to achieve the desired clinical outcome.

METHODS

A retrospective cohort study included 4502 cycles of in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) from January 1, 2016, to June 30, 2019, in a single department. The main outcome measures included retrieved eggs, available embryos, and live birth rate.

RESULTS

The LH_HCG was divided into five groups: Group A (LH ≤ 0.5), Group B (0.5 IU/L < LH ≤ 1.2 IU/L), Group C (1.2 IU/L < LH ≤ 2.0 IU/L), Group D (2.0 IU/L < LH ≤ 5.0 IU/L), Group E (LH > 5 IU/L). In terms of the numbers of retrieved eggs (15.22 ± 5.66 vs. 13.54 ± 5.23 vs. 12.90 ± 5.05 vs. 12.30 ± 4.88 vs. 9.6 ± 4.09), diploid fertilized oocytes (9.85 ± 4.70 vs. 8.69 ± 4.41 vs. 8.39 ± 4.33 vs. 7.78 ± 3.96 vs. 5.92 ± 2.78), embryos (7.90 ± 4.48 vs. 6.83 ± 4.03 vs. 6.44 ± 3.88 vs. 6.22 ± 3.62 vs. 4.40 ± 2.55), and high-quality embryos (4.32 ± 3.71 vs. 3.97 ± 3.42 vs. 3.76 ± 3.19 vs. 3.71 ± 3.04 vs. 2.52 ± 2.27), an increase in the LH_HCG level showed a trend of a gradual decrease. However, there was no significant difference in clinical outcomes among the groups (66.67% vs. 64.33% vs. 63.21% vs. 64.48% vs. 63.33%). By adjusting for confounding factors, with an increase in LH_HCG, the number of retrieved eggs decreased (OR: -0.351 95%CI - 0.453-[- 0.249]).

CONCLUSION

In the follicular-phase long protocol among young women, monitoring LH_HCG is recommended in the clinical guidelines to obtain the ideal number of eggs.

Functional Ovarian Cysts in Artificial Frozen-Thawed Embryo Transfer Cycles With Depot Gonadotropin-Releasing Hormone Agonist

OBJECTIVES

To investigate the incidence of functional ovarian cysts, its influence on clinical rates, and proper management after depot gonadotropin-releasing hormone (GnRH) agonist pretreatment in artificial frozen-thawed embryo transfer cycles (AC-FET).

METHODS

This retrospective cohort study involved 3375 AC-FET cycles with follicular-phase depot GnRH agonist administration between January 2017 and December 2020. Subjects were divided into a study group (cycles with cyst formation) and a control group (cycles without cyst formation). The study group was matched by propensity scoring matching with the control group at a ratio of 1:2. For patients with ovarian cyst formation, two major managements were used: a conservative approach (i.e., expectant treatment) and a drug approach (i.e., continued agonist administration). The primary outcome was live birth rate (LBR).

RESULTS

The incidence of functional ovarian cysts following pituitary downregulation is 10.1% (341/3375). The study group exhibited a LBR similar to the control group (54.5% vs. 50.1%, adjusted odds ratio [aOR] 1.17, 95% confidence interval [CI] 0.88-1.56, P = 0.274). Patients with a lower body mass index and anti-Müllerian hormone, and a higher basal estradiol level were more susceptible to developing functional ovarian cysts. The LBR decreased after the drug approach compared with the conservative approach, but not significantly (aOR 0.63, 95% CI 0.35-1.14, P = 0.125). Following the conservative approach, cycles arrived at live births had a significantly shorter duration from the detection of functional cysts to the start of endometrium preparation (15.7 ± 5.1 days vs. 17.4 ± 5.3 days, P = 0.009) and a significantly higher proportion of ovarian cysts on the initial day of exogenous hormone supplementation (51.4% vs. 30.3%, P = 0.001). After controlling for all confounders, the differences remained statistically significant.

CONCLUSIONS

It is unnecessary to cancel cycles that experience functional ovarian cyst formation. Conservative management and further agonist suppression protocol had similar pregnancy rates. However, a conservative approach was recommended due to its lower cost and fewer side effects. Our findings support a shorter waiting period when choosing the conservative protocol.

The depot GnRH agonist protocol improves the live birth rate per fresh embryo transfer cycle, but not the cumulative live birth rate in normal responders: a randomized controlled trial and molecular mechanism study

STUDY QUESTION

Do cumulative live birth rates (CLBRs) after one complete ART cycle differ between the three commonly used controlled ovarian stimulation (COS) protocols (GnRH antagonist, depot GnRHa (GnRH agonist) and long GnRHa) in normal responders undergoing IVF/ICSI?

SUMMARY ANSWER

There were similar CLBRs between the GnRH antagonist, depot GnRHa and long GnRHa protocols.

WHAT IS KNOWN ALREADY

There is no consensus on which COS protocol is the most optimal in women with normal ovarian response. The CLBR provides the final success rate after one complete ART cycle, including the fresh and all subsequent frozen-thawed embryo transfer (ET) cycles. We suggest that the CLBR measure would allow for better comparisons between the different treatment protocols.

STUDY DESIGN, SIZE, DURATION

A prospective controlled, randomized, open label trial was performed between May 2016 and May 2017. A total of 819 patients were allocated to the GnRH antagonist, depot GnRHa or long GnRHa protocol in a 1:1:1 ratio. The minimum follow-up time from the first IVF cycle was 2 years. To further investigate the potential effect of COS with the GnRH antagonist, depot GnRHa or long GnRHa protocol on endometrial receptivity, the expression of homeobox A10 (HOXA10), myeloid ecotropic viral integration site 1 (MEIS1) and leukemia inhibitory factor (LIF) endometrial receptivity markers was evaluated in endometrial tissue from patients treated with the different COS protocols.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Infertile women with normal ovarian response (n = 819) undergoing IVF/ICSI treatment were randomized to the GnRH antagonist, depot GnRHa or long GnRHa protocol. Both IVF and ICSI cycles were included, and the sperm samples used were either fresh or frozen partner ejaculates or frozen donor ejaculates. The primary outcome was the live birth rate (LBR) per fresh ET cycle, and the CLBR after one complete ART cycle, until the birth of a first child (after 28 weeks) or until all frozen embryos were used, whichever occurred first. Pipelle endometrial biopsies from 34 female patients were obtained on Days 7-8 after oocyte retrieval or spontaneous ovulation in natural cycles, respectively, and HOXA10, MEIS1 and LIF mRNA and protein expression levels in the human endometrium was determined by quantitative real-time PCR and western blot, respectively.

MAIN RESULTS AND THE ROLE OF CHANCE

There were no significant differences in CLBRs between the GnRH antagonist, depot GnRHa or long GnRHa protocol (71.4 versus 75.5 versus 72.2%, respectively). However, there was a significantly higher LBR per fresh ET cycle in the depot GnRHa protocol than in the long GnRHa and GnRH antagonist protocols (62.6 versus 52.1% versus 45.6%, P < 0.05). Furthermore, HOXA10, MEIS1 and LIF mRNA and protein expression in endometrium all showed significantly higher in the depot GnRHa protocol than in the long GnRHa and GnRH antagonist protocols (P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

A limitation of our study was that both our clinicians and patients were not blinded to the randomization for the randomized controlled trial (RCT). An inclusion criterion for the current retrospective cohort study was based on the 'actual ovarian response' during COS treatment, while the included population for the RCT was 'expected normal responders' based on maternal age and ovarian reserve test. In addition, the analysis was restricted to patients under 40 years of age undergoing their first IVF cycle. Furthermore, the endometrial tissue was collected from patients who cancelled the fresh ET, which may include some patients at risk for ovarian hyperstimulation syndrome, however only patients with 4-19 oocytes retrieved were included in the molecular study.

WIDER IMPLICATIONS OF THE FINDINGS

The depot GnRH agonist protocol improves the live birth rate per fresh ET cycle, but not the cumulative live birth rate in normal responders. A possible explanation for the improved LBR after fresh ET in the depot GnRHa protocol could be molecular signalling at the level of endometrial receptivity.

STUDY FUNDING/COMPETING INTEREST(S)

This project was funded by Grant 81571439 from the National Natural Sciences Foundation of China and Grant 2016YFC1000206-5 from the National Key Research & Development Program of China. The authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

The RCT trial was registered at the Chinese Clinical Trial Registry, Study Number: ChiCTR-INR-16008220.

TRIAL REGISTRATION DATE

5 April 2016.

DATE OF FIRST PATIENT’S ENROLLMENT

12 May 2016.

Prolonged pituitary down-regulation with full-dose of gonadotropin-releasing hormone agonist in different menstrual cycles: a retrospective cohort study

Background

The efficiency of prolonged down-regulation caused by a full-dose of gonadotropin-releasing hormone agonist (GnRH-a) injected during different menstrual phases has not yet been researched. Our goal was to evaluate the effects of GnRH-a, which was used in different phases of the menstrual cycle in patients undergoing in vitro fertilization and embryo transfer.

Methods

This was a retrospective cohort study. A total of 320 patients received a prolonged pituitary down-regulated full-dose (3.75 mg) of triptorelin in the early follicular phase, and 160 patients received the same full-dose of triptorelin during the mid-luteal phase. Clinical and laboratory outcomes were compared between the two groups.

Results

The basic characteristics of the two groups were comparable. The mean number of retrieved oocytes, fertilized oocytes, cleavage oocytes and good quality embryos were comparable between the two groups. Although there was a higher antral follicle count, cyst formation rate, fertilization rate and cleavage rate in the follicular phase group, no statistically significant effects were seen on implantation rate (41.15% vs. 45.91%), clinical pregnancy rate (60.38% vs. 61.36%), ongoing pregnancy rate (57.74% vs. 57.58%), live birth rate (56.23% vs. 57.58%) or early abortion rate (2.64% vs. 3.79%) per fresh transfer cycle. Moreover, severe ovarian hyperstimulation syndrome rates at the early stage (1.89% vs. 2.27%) were low in both groups.

Conclusions

Prolonged pituitary down-regulation achieved by utilizing a full-dose of GnRH-a administrated in either phase of the menstrual cycle can have a positive effect on ongoing pregnancy rate and live-birth rate per fresh embryo transfer cycle. Ovarian cyst formation rate was higher in the follicular phase group, but this did not have any adverse impact on clinical results.

Recombinant luteinizing hormone (rLH) and recombinant follicle stimulating hormone (rFSH) for ovarian stimulation in IVF/ICSI cycles

BACKGROUND

One of the various ovarian stimulation regimens used for in-vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) cycles is the use of recombinant follicle-stimulating hormone (rFSH) in combination with a gonadotrophin-releasing hormone (GnRH) analogue. GnRH analogues prevent premature luteinizing hormone (LH) surges. Since they deprive the growing follicles of LH, the question arises as to whether supplementation with recombinant LH (rLH) would increase live birth rates. This is an updated Cochrane Review; the original version was published in 2007.

OBJECTIVES

To compare the effectiveness and safety of recombinant luteinizing hormone (rLH) combined with recombinant follicle-stimulating hormone (rFSH) for ovarian stimulation compared to rFSH alone in women undergoing in-vitro fertilisation/intracytoplasmic sperm injection (IVF/ICSI).

SEARCH METHODS

For this update we searched the following databases in June 2016: the Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, PsycINFO and ongoing trials registers, and checked the references of retrieved articles.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing rLH combined with rFSH versus rFSH alone in IVF/ISCI cycles.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed risk of bias, and extracted data. We combined data to calculate odds ratios (ORs) and 95% confidence intervals (CIs). We assessed statistical heterogeneity using the I² statistic. We assessed the overall quality of the evidence for the main comparisons using GRADE methods. Our primary outcomes were live birth rate and incidence of ovarian hyperstimulation syndrome (OHSS). Secondary outcomes included ongoing pregnancy rate, miscarriage rate and cancellation rates (for poor response or imminent OHSS).

MAIN RESULTS

We included 36 RCTs (8125 women). The quality of the evidence ranged from very low to moderate. The main limitations were risk of bias (associated with poor reporting of methods) and imprecision.Live birth rates: There was insufficient evidence to determine whether there was a difference between rLH combined with rFSH versus rFSH alone in live birth rates (OR 1.32, 95% CI 0.85 to 2.06; n = 499; studies = 4; I² = 63%, very low-quality evidence). The evidence suggests that if the live birth rate following treatment with rFSH alone is 17% it will be between 15% and 30% using rLH combined with rFSH.OHSS: There may be little or no difference between rLH combined with rFSH versus rFSH alone in OHSS rates (OR 0.38, 95% CI 0.14 to 1.01; n = 2178; studies = 6; I² = 10%, low-quality evidence). The evidence suggests that if the rate of OHSS following treatment with rFSH alone is 1%, it will be between 0% and 1% using rLH combined with rFSH.Ongoing pregnancy rate: The use of rLH combined with rFSH probably improves ongoing pregnancy rates, compared to rFSH alone (OR 1.20, 95% CI 1.01 to 1.42; participants = 3129; studies = 19; I² = 2%, moderate-quality evidence). The evidence suggests that if the ongoing pregnancy rate following treatment with rFSH alone is 21%, it will be between 21% and 27% using rLH combined with rFSH.Miscarriage rate: The use of rLH combined with rFSH probably makes little or no difference to miscarriage rates, compared to rFSH alone (OR 0.93, 95% CI 0.63 to 1.36; n = 1711; studies = 13; I² = 0%, moderate-quality evidence). The evidence suggests that if the miscarriage rate following treatment with rFSH alone is 7%, the miscarriage rate following treatment with rLH combined with rFSH will be between 4% and 9%.Cancellation rates: There may be little or no difference between rLH combined with rFSH versus rFSH alone in rates of cancellation due to low response (OR 0.77, 95% CI 0.54 to 1.10; n = 2251; studies = 11; I² = 16%, low quality evidence). The evidence suggests that if the risk of cancellation due to low response following treatment with rFSH alone is 7%, it will be between 4% and 7% using rLH combined with rFSH.We are uncertain whether use of rLH combined with rFSH improves rates of cancellation due to imminent OHSS compared to rFSH alone. Use of a fixed effect model suggested a benefit in the combination group (OR 0.60, 95% CI 0.40 to 0.89; n = 2976; studies = 8; I² = 60%, very low quality evidence) but use of a random effects model did not support the conclusion that there was a difference between the groups (OR 0.82, 95% CI 0.34 to 1.97).

AUTHORS' CONCLUSIONS

We found no clear evidence of a difference between rLH combined with rFSH and rFSH alone in rates of live birth or OHSS. The evidence for these comparisons was of very low-quality for live birth and low quality for OHSS. We found moderate quality evidence that the use of rLH combined with rFSH may lead to more ongoing pregnancies than rFSH alone. There was also moderate-quality evidence suggesting little or no difference between the groups in rates of miscarriage. There was no clear evidence of a difference between the groups in rates of cancellation due to low response or imminent OHSS, but the evidence for these outcomes was of low or very low quality.We conclude that the evidence is insufficient to encourage or discourage stimulation regimens that include rLH combined with rFSH in IVF/ICSI cycles.

Review: Gonadal functioning and preservation of reproductive fitness with juvenile systemic lupus erythematosus

Increased survival of children with juvenile systemic lupus erythematosus (jSLE) and improved prognosis have led to a change in the long-term health issues arising for jSLE patients. Preservation of gonadal functioning and fertility are of increasing importance for young adults with jSLE. Events during childhood, such as exposure to alkylating agents, may compromise the reproductive potential. Even in the absence of gonadotoxic therapies, fertility may be decreased through organs specific involvement with jSLE. Strategies to preserve the reproductive potential of girl and boys with jSLE are discussed. Lupus (2007) 16, 593—599.

Effect of GnRHa 3.75 mg subcutaneously every 6 weeks on adult height in girls with idiopathic central precocious puberty

OBJECTIVE

To evaluate the long-term efficacy of triptorelin 3.75 mg subcutaneously every 6 weeks on the final height in girls with idiopathic central precocious puberty (ICPP).

METHODS

Forty females with ICPP received triptorelin 3.75 mg every 6 weeks subcutaneously in our hospital from 2002 to December 2010 and reached their final heights were enrolled. These patients were treated with triptorelin alone (group A, n=17) or triptorelin+recombinant human growth hormone (rhGH) (group B, n=23). Height, weight, annual growth velocity (GV), sexual development, predicted adult height (PAH), and adverse effects were observed. Bone age (BA) and height standard deviation score (SDS) were monitored yearly.

RESULTS

Final adult heights (FAHs) were 159.81±1.20 cm and 161.01±1.02 cm in group A vs. group B, which exceeded target height (THt) by 1.51±1.04 cm, 4.86±0.94 cm, respectively. The values of (FAH-THt), (FAH-PAH posttreatment) showed significant difference between the two groups (p<0.05). FAH was positively correlated with Ht SDS-BA at the end of treatment, THt, course of rhGH treatment, and age of menarche (r2=0.66). Body mass index (BMI) increased after treatment in group B. However, there was no significant tendency of increase compared with healthy children at the same age. Ages of menarche and time to menarche from discontinuation were 11.74±0.16 vs. 12.18±0.15 years and 17.41±1.69 vs. 14.71±1.04 months in two groups.

CONCLUSION

The FAH was improved effectively by triptorelin 3.75 mg subcutaneously every 6 weeks, and more height gain could be achieved when rhGH was used concomitantly. BMI maintained steadily and ovarian function restored quickly after treatment discontinuation with the age of menarche similar to that of normal children. Neither significant side effect nor polycystic ovary syndrome was observed.

Does prolonged pituitary down-regulation with gonadotropin-releasing hormone agonist improve the live-birth rate in in vitro fertilization treatment?

OBJECTIVE

To evaluate the effects of a prolonged duration of gonadotropin-releasing hormone agonist (GnRH-a) in pituitary down-regulation for controlled ovarian hyperstimulation (COH) on the live-birth rate in nonendometriotic women undergoing in vitro fertilization and embryo transfer (IVF-ET).

DESIGN

Retrospective cohort study.

SETTING

University-affiliated hospital.

PATIENT(S)

Normogonadotropic women undergoing IVF.

INTERVENTION(S)

Three hundred seventy-eight patients receiving a prolonged pituitary down-regulation with GnRH-a before ovarian stimulation and 422 patients receiving a GnRH-a long protocol.

MAIN OUTCOME MEASURE(S)

Live-birth rate per fresh ET.

RESULT(S)

In comparison with the long protocol, the prolonged down-regulation protocol required a higher total dose of gonadotropins. A lower serum luteinizing hormone (LH) level on the starting day of gonadotropin and the day of human chorionic gonadotropin (hCG) and a fewer number of oocytes and embryos were observed in the prolonged down-regulation protocol. However, the duration of stimulation and number of high-quality embryos were comparable between the two groups. A statistically significantly higher implantation rate (50.27% vs. 39.69%), clinical pregnancy rate (64.02% vs. 56.87%) and live-birth rate per fresh transfer cycle (55.56% vs. 45.73%) were observed in the prolonged protocol.

CONCLUSION(S)

Prolonged down-regulation in a GnRH-a protocol might increase the live-birth rates in normogonadotropic women.

Assisted reproductive techniques

Assisted reproductive technologies (ART) encompass fertility treatments, which involve manipulations of both oocyte and sperm in vitro. This chapter provides a brief overview of ART, including indications for treatment, ovarian reserve testing, selection of controlled ovarian hyperstimulation (COH) protocols, laboratory techniques of ART including in vitro fertilization (IVF), and intracytoplasmic sperm injection (ICSI), embryo transfer techniques, and luteal phase support. This chapter also discusses potential complications of ART, namely ovarian hyperstimulation syndrome (OHSS) and multiple gestations, and the perinatal outcomes of ART.

Evaluation of the impact of gonadotropin-releasing hormone agonist as an adjuvant in luteal-phase support on IVF outcome

OBJECTIVES:

To evaluate whether three daily doses of GnRH agonist (Inj. Lupride 1 mg SC) administered 6 days after oocyte retrieval increases ongoing pregnancy rates following embryo transfer (ET) in cycles stimulated with the long GnRH agonist protocol.

SETTINGS AND DESIGN:

Prospective randomized controlled study in a tertiary care center.

MATERIALS AND METHODS:

Four hundred and twenty six women undergoing ET following controlled ovarian stimulation with a long GnRH agonist protocol were included. In addition to routine luteal-phase support (LPS) with progesterone, women were randomized to receive three 1 mg doses of Lupride 6 days after oocyte retrieval. Computer-generated randomization was done on the day of ET. Ongoing pregnancy rate beyond 20^th week of gestation was the primary outcome measure. The trial was powered to detect a 13% absolute increase from an assumed 27% ongoing pregnancy rate in the control group, with an alpha error level of 0.05 and a beta error level of 0.2.

RESULTS:

There were 59 (27.69%) ongoing pregnancies in the GnRHa group, and 56 (26.29%) in the control group (P = 0.827). Implantation, clinical pregnancy and multiple pregnancy rates were likewise similar in the GnRHa and placebo groups.

CONCLUSIONS:

Three 1 mg doses of Lupride administration 6 days after oocyte retrieval in the long protocol cycles does not result in an increase in ongoing pregnancy rates.

Duration of luteal support (DOLS) with progesterone pessaries to improve the success rates in assisted conception: study protocol for a randomized controlled trial

Background

Luteal support with progesterone is necessary for successful implantation of the embryo following egg collection and embryo transfer in an in-vitro fertilization (IVF) cycle. Progesterone has been used for as little as 2 weeks and for as long as 12 weeks of gestation. The optimal length of treatment is unresolved at present and it remains unclear how long to treat women receiving luteal supplementation.

Design

The trial is a prospective, randomized, double-blind, placebo-controlled trial to investigate the effect of the duration of luteal support with progesterone in IVF cycles. Following 2 weeks standard treatment and a positive biochemical pregnancy test, this randomized control trial will allocate women to a supplementary 8 weeks treatment with vaginal progesterone or 8 weeks placebo. Further studies would be required to investigate whether additional supplementation with progesterone is beneficial in early pregnancy.

Discussion

Currently at the Hewitt Centre, approximately 32.5% of women have a positive biochemical pregnancy test 2 weeks after embryo transfer. It is this population that is eligible for trial entry and randomization. Once the patient has confirmed a positive urinary pregnancy test they will be invited to join the trial. Once the consent form has been completed by the patient a trial prescription sheet will be sent to pharmacy with a stated collection time. The patient can then be randomized and the drugs dispensed according to pharmacy protocol. A blood sample will then be drawn for measurement of baseline hormone levels (progesterone, estradiol, free beta-human chorionic gonadotrophin, pregnancy-associated plasma protein-A, Activin A, Inhibin A and Inhibin B). The primary outcome measure is the proportion of all randomized women that continue successfully to a viable pregnancy (at least one fetus with fetal heart rate >100 beats/minute) on transabdominal/transvaginal ultrasound at 10 weeks post embryo transfer/12 weeks gestation (that is at the end of 8 weeks supplementary trial treatment).

Trial registration

ISRCTN05696887

Drug delivery for in vitro fertilization: rationale, current strategies and challenges

In vitro fertilization has experienced phenomenal progress in the last thirty years and awaits the additional refinement and enhancement of medication delivery systems. Opportunity exists for the novel delivery of gonadotropins, progesterone and other adjuvants. This review highlights the rationale for various medications, present delivery methods and introduces the status of novel ideas and possibilities.

WITHDRAWN: Luteal phase support in assisted reproduction cycles

BACKGROUND

The aspiration of the granulosa cells that surround the oocyte and the use of gonadotropin releasing hormone agonists (GnRHa) during assisted reproduction technology (ART) treatment can interfere with the production, during the luteal phase, of progesterone, which is necessary for successful implantation of the embryo. Providing hormonal supplementation during the luteal phase with either progesterone itself, or human chorionic gonadotropin (hCG), which stimulates progesterone production, may improve implantation and, thus, pregnancy rates.

OBJECTIVES

To determine (1) if luteal phase support after assisted reproduction increases the pregnancy rate, (2) the optimal hormone for luteal phase support, i.e. hCG, progesterone, or a combination of both, and (3) the optimal route of progesterone administration.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders & Subfertility Group trials register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (1971 to Dec 2003), EMBASE (1985 to Dec 2003). We handsearched reference lists of relevant articles were scanned, and abstract books from scientific meetings up to December 2003.

SELECTION CRITERIA

Randomized controlled trials of luteal phase support after ART treatment, comparing hCG or progesterone with placebo or no treatment, comparing progesterone with hCG, progesterone plus hCG, or progesterone plus estrogen, or comparing different routes of progesterone administration. Quasi-randomized trials were excluded from the main analyses, but included in a secondary analysis for each comparison.

DATA COLLECTION AND ANALYSIS

For each comparison, data on live birth, ongoing and clinical pregnancy per embryo or gamete transfer procedure, miscarriage per clinical pregnancy, ovarian hyperstimulation syndrome (OHSS) per transfer, and multiple pregnancy per clinical pregnancy were extracted into 2 x 2 tables and subgrouped by use of GnRHa in the ovarian stimulation regimen. The odds ratio (OR) and risk difference (RD) were calculated.

MAIN RESULTS

Fifty-nine studies were included in the review. Luteal phase support with hCG provided significant benefit, compared to placebo or no treatment, in terms of increased ongoing pregnancy rates (odds ratio (OR) 2.38, 95% confidence interval (CI) 1.32 to 4.29) and decreased miscarriage rates (OR 0.12, 95% CI 0.03 to 0.50), but only when GnRHa was used. The odds of OHSS increased 20-fold when hCG was used in cycles with GnRHa. Progesterone use resulted in a small but significant increase in pregnancy rates (OR 1.34, 95% CI 1.01 to 1.79) when trials with and without GnRHa were grouped together, but no effect on the miscarriage rate was observed. No significant difference was found between progesterone and hCG or between progesterone and progesterone plus hCG or estrogen in terms of pregnancy or miscarriage rates, but the odds of OHSS were more than 2-fold higher with treatments involving hCG than with progesterone alone(OR 3.06, 95% CI 1.59 to 5.86). Comparing routes of progesterone administration, reductions in clinical pregnancy rate with the oral route, compared to the intramuscular or vaginal routes, did not reach statistical significance, but there was evidence of benefit of the intramuscular over the vaginal route for the outcomes of ongoing pregnancy and live birth. No significant difference in pregnancy rate was observed between vaginal progesterone gel and other types of vaginal progesterone.

AUTHORS' CONCLUSIONS

Luteal phase support with hCG or progesterone after assisted reproduction results in an increased pregnancy rate. hCG does not provide better results than progesterone, and is associated with a greater risk of OHSS when used with GnRHa. The optimal route of progesterone administration has not yet been established.

Recombinant Luteinizing Hormone (rLH) for controlled ovarian hyperstimulation in assisted reproductive cycles

BACKGROUND

During in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatment cycles, controlled ovarian hyperstimulation (COH) is performed with recombinant follicle stimulating hormone (rFSH) in combination with a gonadotrophin-releasing hormone (GnRH) analogue for the prevention of premature luteinizing hormone (LH) surges. The use of GnRH analogues however deprives the growing follicles of LH. The effectiveness of co-administrating rLH to rFSH for COH is at present unclear.

OBJECTIVES

To compare the effectiveness and safety of a combination of recombinant LH and recombinant FSH with recombinant FSH alone in COH protocols in (IVF or ICSI followed by embryo transfer (ET).

SEARCH STRATEGY

We searched the MDSG Group Specialised Register (searched up to Nov 2006) and CENTRAL, MEDLINE and EMBASE (1980 to November 2006) and reference lists of articles.

SELECTION CRITERIA

Randomised controlled trials comparing COH with rFSH alone or in combination with rLH in IVF/ICSI were included.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trial quality and extracted data. We sought additional information if necessary.

MAIN RESULTS

Fourteen trials involving 2612 women were included. Eleven trials involving 2396 women used a GnRH agonist . There was no evidence of a statistical difference in live birth rate reported in two trials (OR 1.51, 95% CI 0.79 to 2.87). There was no evidence of a statistical difference in clinical pregnancy rates reported in seven trials OR 1.15, 95% CI 0.91 to 1.45. There was no evidence of a statistical difference or in ongoing pregnancy rates seven trials OR 1.22, 95% CI 0.95 to 1.56. Three trials used a GnRH antagonist. No data on live birth rates was available. There was no evidence of a statistical difference in clinical pregnancy rates (one trial: OR 0.79, 95% CI 0.26 to 2.43) or in ongoing pregnancy rates (two trials: OR 0.83, 95% CI 0.39 to 1.80) comparing both groups. The pooled pregnancy estimates of trials including only poor responders showed significant increase in pregnancy rate, in favour of co-administrating rLH (three trials: OR 1.85, 95% CI 1.10 to 3.11)

AUTHORS' CONCLUSIONS

There was no evidence of a statistical difference in pregnancy outcomes when rLH was used. Nevertheless, further large RCTs should be undertaken in long GnRH agonist down regulation protocols, since all pooled pregnancy estimates, although not statistically different probably due to the small numbers, point towards a beneficial effect of co-treatment with rLH, in particular with respect to pregnancy-loss and poor-responders.

Actions of gonadotropin-releasing hormone analogues in pituitary gonadotrophs and their modulation by ovarian steroids

Recently, GnRH antagonists (GnRHant) like cetrorelix and ganirelix have been introduced in protocols of controlled ovarian hyperstimulation for assisted reproductive techniques to prevent premature luteinizing hormone (LH) surges. Here we tested, whether the actions of cetrorelix and the GnRH agonist (GnRHag) triptorelin in gonadotrophs are dependent on the steroid milieu. Furthermore, we characterized the actions of cetrorelix and triptorelin on LH secretion and the total LH pool. Female rat pituitary cells were treated either with 0.1 nM triptorelin for 1, 2, 4 and 6 days or for 1, 3, 5 and 6 h or with 1, 10 or 100 nM cetrorelix for 1, 2, 3 and 5 h or for 10 min. Cells were stimulated for 3h with different concentrations of GnRH (10 pM-1 microM). For analysis of the total LH pool, which is composed of stored and released LH, cells were lysed with 0.1% Triton X-100 at -80 degrees C overnight. To test, whether the steroid milieu affects the actions of cetrorelix and triptorelin, cells were incubated for 52 h with 1 nM estradiol (E) alone or with combinations of 100 nM progesterone (P) for 4 or 52 h, respectively. Cells were then treated with 0.1 nM triptorelin for 9 h or 1 nM cetrorelix for 3 h and stimulated for 3 h with different concentrations of GnRH (10 pM-1 microM). The suppressive effect of triptorelin on LH secretion was fully accomplished after 3 h of treatment, for cetrorelix only 10 min were sufficient. The concentration of cetrorelix must be at least equimolar to GnRH to block LH secretion. Cetrorelix shifted the EC50s of the GnRH dose-response curve to the right. Triptorelin suppressed total LH significantly (from 137 to 36 ng/ml) after 1 h in a time-dependent manner. In contrast, only high concentrations of cetrorelix increased total LH. In steroid treated cells the suppressive effects of triptorelin were more distinct. One nanomolar cetrorelix suppressed GnRH-stimulated LH secretion of cells not treated with steroids from 10.1 to 3.5 ng/ml. In cells, additionally treated with estradiol alone or estradiol and short-term progesterone, LH levels were higher (from 3.5 to 5.4 or 4.5 ng/ml, respectively). In cells co-treated with estradiol and progesterone for 52 h LH secretion was only suppressed from 10.1 to 9.5 ng/ml. Steroid treatments diminished the suppressive effect of cetrorelix on LH secretion. In conclusion, the depletion of the total LH pool contributes to the desensitizing effect of triptorelin. The actions of cetrorelix and triptorelin are dependent on the steroid milieu.

Pituitary desensitization for eight weeks after the administration of two distinct gonadotrophin-releasing hormone agonists

OBJECTIVE(S)

The objective was to evaluate the duration of pituitary desensitization after the administration of 3.5 mg of triptorelin (T) and leuprolin (L) depot preparations in patients with endometriosis.

STUDY DESIGN

Two groups of 30 patients received, on 21st day of the cycle, 3.75 mg i.m. of triptorelin (T group), and of leuprolin acetate (L group). From the first to the eighth week following gonadotrophin-releasing hormone agonists (GnRH-a) administration both groups underwent pelvic ultrasound and serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and estradiol (E2) evaluation. Statistical analysis was performed using the ANOVA test and the median test. A p-value < 0.05 was considered significant.

RESULTS

Pituitary suppression was achieved from two to six and from two to seven weeks after the administration of 3.75 mg of leuprolin and triptorelin, respectively. FSH and LH serum levels were significantly higher in the L group than in the T group after the fourth week.

CONCLUSIONS

Leuprolin and triptorelin depots (3.75 mg) promote satisfactory ovarian suppression lasting for six and seven weeks, respectively, after administration, with significantly different ambient levels of endogenous LH.

Luteal phase support in assisted reproduction cycles

BACKGROUND

The aspiration of the granulosa cells that surround the oocyte and the use of gonadotropin releasing hormone agonists (GnRHa) during assisted reproduction technology (ART) treatment can interfere with the production, during the luteal phase, of progesterone, which is necessary for successful implantation of the embryo. Providing hormonal supplementation during the luteal phase with either progesterone itself, or human chorionic gonadotropin (hCG), which stimulates progesterone production, may improve implantation and, thus, pregnancy rates.

OBJECTIVES

To determine (1) if luteal phase support after assisted reproduction increases the pregnancy rate, (2) the optimal hormone for luteal phase support, i.e. hCG, progesterone, or a combination of both, and (3) the optimal route of progesterone administration.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders & Subfertility Group trials register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (1971 to Dec 2003), EMBASE (1985 to Dec 2003). We handsearched reference lists of relevant articles were scanned, and abstract books from scientific meetings up to December 2003.

SELECTION CRITERIA

Randomized controlled trials of luteal phase support after ART treatment, comparing hCG or progesterone with placebo or no treatment, comparing progesterone with hCG, progesterone plus hCG, or progesterone plus estrogen, or comparing different routes of progesterone administration. Quasi-randomized trials were excluded from the main analyses, but included in a secondary analysis for each comparison.

DATA COLLECTION AND ANALYSIS

For each comparison, data on live birth, ongoing and clinical pregnancy per embryo or gamete transfer procedure, miscarriage per clinical pregnancy, ovarian hyperstimulation syndrome (OHSS) per transfer, and multiple pregnancy per clinical pregnancy were extracted into 2 x 2 tables and subgrouped by use of GnRHa in the ovarian stimulation regimen. The odds ratio (OR) and risk difference (RD) were calculated.

MAIN RESULTS

Fifty-nine studies were included in the review. Luteal phase support with hCG provided significant benefit, compared to placebo or no treatment, in terms of increased ongoing pregnancy rates (odds ratio (OR) 2.38, 95% confidence interval (CI) 1.32 to 4.29) and decreased miscarriage rates (OR 0.12, 95% CI 0.03 to 0.50), but only when GnRHa was used. The odds of OHSS increased 20-fold when hCG was used in cycles with GnRHa. Progesterone use resulted in a small but significant increase in pregnancy rates (OR 1.34, 95% CI 1.01 to 1.79) when trials with and without GnRHa were grouped together, but no effect on the miscarriage rate was observed. No significant difference was found between progesterone and hCG or between progesterone and progesterone plus hCG or estrogen in terms of pregnancy or miscarriage rates, but the odds of OHSS were more than 2-fold higher with treatments involving hCG than with progesterone alone(OR 3.06, 95% CI 1.59 to 5.86). Comparing routes of progesterone administration, reductions in clinical pregnancy rate with the oral route, compared to the intramuscular or vaginal routes, did not reach statistical significance, but there was evidence of benefit of the intramuscular over the vaginal route for the outcomes of ongoing pregnancy and live birth. No significant difference in pregnancy rate was observed between vaginal progesterone gel and other types of vaginal progesterone.

REVIEWERS' CONCLUSIONS

Luteal phase support with hCG or progesterone after assisted reproduction results in an increased pregnancy rate. hCG does not provide better results than progesterone, and is associated with a greater risk of OHSS when used with GnRHa. The optimal route of progesterone administration has not yet been established.

A short review of ovarian stimulation in assisted reproductive techniques

Ovarian stimulation during assisted human reproduction is currently a standard procedure in assisted reproductive techniques (ART). Its objective is to stimulate the growth of several follicles by injections of FSH-containing compounds, most recently recombinant FSH (rFSH). An injection of human chorionic gonadotrophin (HCG), or a luteinizing hormone-releasing hormone agonist to discharge pituitary LH is then given to invoke follicle and oocyte maturation. Various other medications are also used in addition to specific drugs such as human menopausal gonadotrophin, rFSH, HCG and rLH. Non-specific drugs include clomiphene citrate, other anti-oestrogens, bromoergocryptine, and gonadotrophin-releasing hormone (GnRH) agonists and antagonists. Numerous protocols have been utilized with these agents, the most common being clomiphene citrate and various regimens of gonadotrophins, including step-up, step-down and continuous. The regimens are used with or without GnRH agonists, and with or without GnRH antagonists. In this brief review, the advantages and disadvantages of each protocol are presented.

A comparison of three gonadotrophin-releasing hormone analogues in an in-vitro fertilization programme: a prospective randomized study

The use of gonadotrophin-releasing hormone analogues (GnRHa) has resulted in improved pregnancy rates in in-vitro fertilization (IVF) treatment cycles. Traditionally, short-acting analogues have been employed because of concerns over long-acting depot preparations causing profound suppression and luteal phase defects adversely affecting pregnancy and miscarriage rates. We randomized 60 IVF patients to receive a short-acting GnRHa, nafarelin or buserelin, or to receive a depot formulation, leuprorelin, all commenced in the early follicular phase and compared their effects on hormonal suppression and clinical outcome. We found that on day 15 of administration there was a significant difference in the suppression of oestradiol from initial concentrations, when patients on buserelin were compared with patients on nafarelin or leuprorelin (54 versus 72 and 65%; P < 0.05) and also in the number of patients satisfactorily suppressed, (80 versus 90 and 90%; P < 0.05), though there were no differences between the analogues by day 21. Similarly there was no difference in hormonal suppression during the stimulation phase or in implantation, pregnancy or miscarriage rates in comparing the three agonists. We conclude that with nafarelin and leuprorelin, stimulation with gonadotrophins may begin after 2 weeks of suppression and that long-acting GnRHa are as effective as short-acting analogues with no detrimental effects on the luteal phase.

Pituitary down-regulation with a single depot-dose of a GnRH agonist (triptorelin) in postmenopausal women

Gonadotropin levels were determined in 17 postmenopausal women before and after administering a single depot-dose of the GnRH agonist triptorelin. E2 levels of all samples were in the normal (low) postmenopausal range and no differences were found when the patients were grouped according to chronological age, or time after menopause. Pre-GnRH agonist levels of LH and FSH were in the normal (high) postmenopausal range. Two weeks after medication, LH and FSH had decreased to premenopausal levels (P < 0.0001). Eight weeks after medication, LH levels were still low whereas FSH levels had risen significantly again (P < 0.0001). Both LH and FSH levels, however, were still significantly below the serum concentrations before the administration of triptorelin (P < 0.0001). The pre-GnRH agonist level of FSH was significantly higher in women > 67 years old (P < 0.05), as compared to women < 67 years. Two weeks after medication both LH and FSH levels were significantly higher in women more than 15 years after menopause (P < 0.05), as compared to those < 15 years. The same was found for FSH in women > 67 years old. No further significant differences were noted. This study demonstrates a significant decrease of LH and FSH serum levels in postmenopausal women within two weeks after administration of a single depot-dose of the GnRH agonist triptorelin. After eight weeks, in contrast to premenopausal women, both LH and FSH, although rising, were still significantly suppressed.

Pituitary responsiveness after administration of a GnRH agonist depot formulation: Decapeptyl CR

OBJECTIVE

This study was focused on the pattern of LH release from the pituitary during the initial response to high dose GnRH agonist administration. Secondly, the pattern of LH release and the pituitary responsiveness to physiological and pharmacological stimulation during long-term pituitary suppression by a high dose GnRH agonist was studied. In addition, the relation between serum agonist levels and pituitary function and responsiveness was investigated.

DESIGN

DTrp6GnRH in microcapsules (Decapeptyl CR) was administered i.m. to 12 women on the third day of the cycle. High-rate blood sampling was carried out during the first 48 hours after the injection. Secondly, high-rate blood sampling for 6 hours and a GnRH challenge were performed before and weekly after administration, from week 4 till week 9. All samples were assayed for LH and FSH. LH patterns were analysed by applying a computerized pulse detection program. In the second or third week an oestradiol benzoate test was performed. Finally, triptorelin levels were measured before and weekly after administration.

PATIENTS

Twelve patients, suffering from tubal infertility and recruited from the waiting list for in-vitro fertilization/embryo transfer (IVF/ET) participated in the study.

RESULTS

During the first 48-hour period, LH and FSH levels demonstrated a rapid rise to peak values after 4 hours, subsequently declining to nearly normal levels. E2 rose to peak values at 12 hours and returned to the follicular range thereafter. LH pulse patterns showed a rapid increase in pulse intervals leading to a near absence of LH pulses at the end of the 48-hour period. From the fourth till the seventh week after agonist administration, LH pulse patterns showed a markedly increased pulse interval, decreased pulse amplitude, and a severely decreased mean LH level. In the same period, LH responses to GnRH were severely blunted or absent. Restoration of the pre-injection LH pulse pattern and the LH response to GnRH was observed during the eighth and ninth week. Oestradiol benzoate challenges showed an E2 rise to preovulatory levels in response to the injections. However, no changes were observed in LH and FSH concentrations. Triptorelin levels showed a peak within 48 hours and gradual decline towards pretreatment values in week eight.

CONCLUSIONS

It is concluded from the study, that after administration of triptorelin depot in the early follicular phase, desensitization of the pituitary starts to develop within 24 hours. Pituitary responsiveness is completely absent in the second week and continues to exist until the eighth week after injection, when the agonist has disappeared from the circulation. These findings suggest profound alterations in GnRH receptor availability and post-receptor pathways, that prevent the pituitary from responding to physiological stimuli.