Can GnRH agonists act directly on the ovary and contribute to cyst formation?

Comparison of Cumulative Live Birth Rates Between Progestin and GnRH Analogues in Preimplantation Genetic Testing Cycles

CONTEXT

Progestins have recently been used as an alternative for gonadotropin-releasing hormone (GnRH) analogues to prevent premature luteinizing hormone surge due to the application of vitrification technology. However, the long-term efficacy and safety of a progestin-primed ovarian stimulation (PPOS) regimen, including oocyte competence, cumulative live birth rate (LBR), and offspring outcomes, remain to be investigated.

OBJECTIVE

To compare cumulative LBR of preimplantation genetic testing (PGT) cycles between a PPOS regimen and GnRH analogues.

METHODS

This was a retrospective cohort study at a tertiary academic medical center. A total of 967 patients with good prognosis were categorized into 3 groups, of which 478 patients received a long GnRH agonist, 248 patients received a GnRH antagonist, and 250 received a PPOS regimen. Medroxyprogesterone 17-acetate was the only progestin used in the PPOS regimen. The primary outcome was cumulative LBR. Secondary outcomes included time to live birth, cumulative rates of biochemical and clinical pregnancy and pregnancy loss, and perinatal outcomes.

RESULTS

The PPOS regimen was negatively associated with cumulative LBR compared with GnRH antagonists and GnRH agonists (28.4% vs 40.7% and 42.7%). The average time to live birth was significantly shorter with GnRH antagonists than with the PPOS regimen. The cumulative biochemical and clinical pregnancy rates were also lower in the PPOS regimen than GnRH analogues, while cumulative pregnancy loss rates were similar across groups. Furthermore, the number and ratio of good-quality blastocysts were significantly reduced in the PPOS regimen compared with GnRH analogues. In addition, perinatal outcomes were comparable across 3 groups.

CONCLUSION

A PPOS regimen may be adversely affect cumulative LBR and blastocyst quality in women with good prognosis compared with GnRH analogues in PGT cycles.

Gonadotropin-releasing hormone analogs: Mechanisms of action and clinical applications in female reproduction

Extra-hypothalamic GnRH and extra-pituitary GnRH receptors exist in multiple human reproductive tissues, including the ovary, endometrium and myometrium. Recently, new analogs (agonists and antagonists) and modes of GnRH have been developed for clinical application during controlled ovarian hyperstimulation for assisted reproductive technology (ART). Additionally, the analogs and upstream regulators of GnRH suppress gonadotropin secretion and regulate the functions of the reproductive axis. GnRH signaling is primarily involved in the direct control of female reproduction. The cellular mechanisms and action of the GnRH/GnRH receptor system have been clinically applied for the treatment of reproductive disorders and have widely been introduced in ART. New GnRH analogs, such as long-acting GnRH analogs and oral nonpeptide GnRH antagonists, are being continuously developed for clinical application. The identification of the upstream regulators of GnRH, such as kisspeptin and neurokinin B, provides promising potential to develop these upstream regulator-related analogs to control the hypothalamus-pituitary-ovarian axis.

Progestins for pituitary suppression during ovarian stimulation for ART: a comprehensive and systematic review including meta-analyses

BACKGROUND

Progestins are capable of suppressing endogenous LH secretion from the pituitary. Progestins can be used orally and are less expensive than GnRH analogues. However, early endometrial exposure to progestin precludes a fresh embryo transfer (ET), but the advent of vitrification and increasing number of oocyte cryopreservation cycles allow more opportunities for using progestins for pituitary suppression.

OBJECTIVE AND RATIONALE

This review summarizes: the mechanism of pituitary suppression by progestins; the effectiveness of progestins when compared with GnRH analogues and with each other; the effect of progestins on oocyte and embryo developmental potential and euploidy status; and the cost-effectiveness aspects of progestin primed stimulation. Future research priorities are also identified.

SEARCH METHODS

The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE via PubMed, the Web of Science and Scopus were screened with a combination of keywords related to ART, progesterone, GnRH analogue and ovarian stimulation, in various combinations. The search period was from the date of inception of each database until 1 April 2020. Only full text papers published in English were included.

OUTCOMES

Overall, the duration of stimulation, gonadotrophin consumption and oocyte yield were similar with progestins and GnRH analogues. However, sensitivity analyses suggested that progestins were associated with significantly lower gonadotrophin consumption than the long GnRH agonist protocol (mean difference (MD) = -648, 95% CI = -746 to -550 IU) and significantly higher gonadotrophin consumption than the short GnRH agonist protocol (MD = 433, 95% CI = 311 to 555 IU). Overall, live birth, ongoing and clinical pregnancy rates per ET were similar with progestins and GnRH analogues. However, when progestins were compared with GnRH agonists, sensitivity analyses including women with polycystic ovary syndrome (risk ratio (RR) = 1.27, 95% CI = 1.06 to 1.53) and short GnRH agonist protocols (RR = 1.14, 95% CI = 1.02 to 1.28) showed significantly higher clinical pregnancy rates with progestins. However, the quality of evidence is low. Studies comparing medroxyprogesterone acetate, dydrogesterone and micronized progesterone suggested similar ovarian response and pregnancy outcomes. The euploidy status of embryos from progestin primed cycles was similar to that of embryos from conventional stimulation cycles. Available information is reassuring regarding obstetric and neonatal outcomes with the use of progestins. Despite the lower cost of progestins than GnRH analogues, the mandatory cryopreservation of all embryos followed by a deferred transfer may increase cost per live birth with progestins as compared to an ART cycle culminating in a fresh ET.

WIDER IMPLICATIONS

Progestins can present an effective option for women who do not contemplate a fresh ET, e.g. fertility preservation, anticipated hyper responders, preimplantation genetic testing, oocyte donors, double stimulation cycles.

Outcomes from ovarian hyperstimulation following the sole administration of gonadotrophin-releasing hormone agonist in the context of in vitro fertilization: report of two cases and review of the literature

OBJECTIVE

To report the outcomes from two cases of ovarian stimulation following the sole administration of gonadotrophin-releasing hormone agonist (GnRHa) in the context of in vitro fertilization (IVF).

DESIGN

A case study was conducted.

SETTING

National Referral Unit of Reproductive Medicine.

PATIENTS

Two infertile women undergoing IVF participated in the study.

INTERVENTIONS

Controlled ovarian hyperstimulation using a long protocol. GnRHa (Buserelin) was started in the luteal phase, in a dose of 600 µg/day, for 12 days.

MAIN OUTCOME MEASURES

Number of retrieved oocytes, fertilization rate, number of embryos transferred, implantation rate, ongoing pregnancy, and live birth.

RESULTS

Both women underwent egg retrieval and transfer of good quality embryos. One of them conceived and recently gave birth to a healthy full-term baby.

CONCLUSIONS

The ovarian hyperstimulation after the sole administration of GnRHa is a rare condition. Oocyte retrieval may be a reasonable treatment under these circumstances instead of cycle cancellation. As far as it is known, this is the third case reported of a live birth following the sole administration of GnRHa in the context of IVF.

Clinical and endocrine response to the withdrawal of gonadotropin-releasing hormone agonists during prolonged coasting

OBJECTIVE

To compare the clinical and endocrine response of cycles in which GnRH agonists (GnRH-a) were stopped with cycles in which the agonists were continued during coasting.

DESIGN

Retrospective study of stimulation cycles using flare and luteal agonist protocols.

SETTING

Academic.

PATIENT(S)

Fifty-nine IVF and intracytoplasmic sperm injection (ICSI) treatment cycles in 57 women, coasted for 3 or more days.

INTERVENTION(S)

The GnRH-a were withdrawn when E(2) levels continued to increase during coasting.

MAIN OUTCOME MEASURE(S)

Hormone concentrations, ultrasound findings, cycle cancellation, ovarian hyperstimulation syndrome (OHSS), oocyte retrieval, fertilization, embryo transfer, and clinical pregnancy rates (PR).

RESULT(S)

In the GnRH-a withdrawn group E(2) levels decreased by 63% (18,043-6,656 pmol/L) without cycle cancellations or cases of severe OHSS. In the agonist continuation group, the spontaneous E(2) decrease was 29% (14,205-10,132 pmol/L) with cycle cancellation and severe OHSS rates of 9.5% (4/42) and 4.8% (2/42), respectively. Oocyte retrieval, fertilization, embryo transfer, and clinical PRs were not compromised by stopping the agonists. Variations in the dynamic responses of FSH, LH, anti-Müllerian hormone, P, and androstenedione (A) levels in these cycles are described.

CONCLUSION(S)

Withdrawal of GnRH-a during coasting interrupted increasing E(2) levels, prevented cycle cancellation, and mitigated the risk of OHSS in this high risk group without compromising oocyte retrieval, fertilization, embryo transfer, or PRs.

Hyperstimulation ovarienne induite par un agoniste de la GnRH. À propos d'un cas

We report a case of ovarian hyperstimulation induced by a GnRH agonist (Decapeptyl in a patient aged of 23 years and having 3 years of primary infertility of male origin. Twelve days after agonist administration, several ovarian follicles, great-sized, and with a rate of elevated serum oestradiol have been noted. After triggering of the ovulation by 5000 IU of HCG, oocyte retrieval permitted the collection of 4 oocytes 3 of which were mature. Only one embryo with 4 cells has been transferred 48 hours after intracytoplasmic sperm injection fertilization (ICSI), but there was no pregnancy. Ovarian hyperstimulation induced by GnRH agonist is a rare event and only a few cases have been reported. The development of multiple follicles after the administration of an agonist is a paradoxal answer of the ovary to the pituitary desensitization without a clarified physiopathology. The hypothesis of a direct action of the agonist on the ovary is likeliest. Triggering of ovulation by human chorionic gonadotrophin (HCG) has been achieved by certain authors. Fertilization of oocytes and transfers of embryos have succeeded in certain cases, but only one pregnancy has been reported that led to a living birth.

Gonadotropin-releasing hormone and reproductive medicine

The hypothalamic gonadotropin-releasing hormone (GnRH) is a key regulator of the reproductive system, mainly through its effects on pituitary luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release. Gonadotropin-releasing hormone analogues are modifications of the natural decapeptide, being either agonists (GnRHa) or antagonists. GnRHa may imitate the native hormone and induce an endogenous LH surge; however, sustained treatment with GnRHa results in complete refractoriness of LH and FSH production. This aspect of GnRHa action is the main application of the GnRHa in reproduction today. The hypogonadotropic hypogonadal state that results from the sustained treatment is the basis for additional applications of the GnRHa. The agonists appear to be effective, to some extent, for the treatment of endometriosis and were proved to be beneficial prior to surgery for fibroma uteri. GnRHa is used in assisted reproduction for both induction of an endogenous LH surge and for induction of ovulation, and its capacity to cause refractoriness of the pituitary may be used to avoid a premature LH surge. It is suggested that the GnRHa have a direct effect on ovarian steroidogenesis, which is independent of its action on the pituitary. This unwanted effect and other possible drawbacks of the agonists are thought to be eliminated with the use of the antagonists. The mechanism of action of these antagonists is through competitive blocking of the GnRH receptor, which results in a rapid but reversible suppression of gonadotropin secretion. As for GnRHa, GnRH antagonists have been proven effective to prevent the LH surge and to reduce the incidence of severe ovarian hyperstimulation syndrome in controlled ovarian stimulation cycles.

The role of LHRH agonists and antagonists

Administration of GnRH analogues (agonists as well as antagonists) produces suppression of the pituitary---gonadal axis, thus inhibiting the secretion of LH, FSH and sexual steroids. For this reason, analogs are indicated in all those clinical situations where suppression of gonadotrophins (precocious puberty, contraception) or of sexual steroids (endometriosis, prostate hyperplasia, cancer, uterine fibroids) is desired. For several years GnRH agonists have been used in combination with gonadotrophins for ovarian stimulation for assisted reproduction in order to control premature LH surges and to reduce cancellation rate with improvement of the pregnancy rate per cycle. This effect is obtained after 2 weeks of agonist administration. The immediate suppression of the pituitary achieved by GnRH antagonists without an initial stimulatory effect is the main advantage of these compounds over the agonists. The prevention of a premature LH surge by GnRH antagonists can be obtained by multiple dose or by a single administration. Both protocols offer the following advantages over the agonists: they require fewer ampoules of gonadotrophins, shorter duration of stimulation, there is a preserved pituitary response to GnRH, less risk of ovarian hyperstimulation syndrome and the luteal phase seems to be more preserved. The main disadvantages of the antagonists are that they are expensive and that pregnancy rate appears to be slightly lower than with the agonists. GnRH antagonists will probably replace agonists in ovarian stimulation treatment for assisted reproduction techniques.

Embryo implantation and GnRH antagonists: ovarian actions of GnRH antagonists

The gonadotrophin-releasing hormone (GnRH) antagonists, cetrorelix and ganirelix, have both been approved for ovarian stimulation to prevent a premature LH surge. Since GnRH receptors and their gene expression have been detected in human ovary, concern has risen over whether GnRH antagonists might affect ovarian function. Three large trials which compared GnRH agonists (used in the standard protocol worldwide), with the new antagonist treatment found no significant differences concerning the most important goals, e.g. pregnancy rate, fertilization and quality of oocytes. However, the concentration of oestradiol, and the pregnancy and implantation rates were lower in GnRH antagonist-treated patients. These findings again fuelled the debate about the possible extrapituitary effects of GnRH antagonists. Here, we review the conflicting data in the literature on the ovarian effects of GnRH antagonists and discuss our own results. In our view, it is unlikely that GnRH antagonists have a relevant impact on ovarian steroidogenesis and function; however, GnRH antagonists may exert other effects on the ovary.