Basic understanding of gonadotropin-releasing hormone–agonist triggering

Casper, Robert F.

doi:10.1016/j.fertnstert.2014.12.129

Cited by 44 publications

(33 citation statements)

References 17 publications

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“…In humans, estrogen has been shown to have positive feedback effects on specific kisspeptin neurons that regulate GnRH release. 27 Although not all species respond similarly, in the pig, estrogen acts at the central nervous system to modulate GnRH. 28 Administration of estrogen has been shown to induce the LH surge, but initially induces a temporary LH decline, 29 which is thought to be important for allowing the pituitary to build up LH stores, for surge release 24–48 hours later.…”

Section: Control Of Gnrh Releasementioning

confidence: 99%

Recent advancements in the hormonal stimulation of ovulation in swine

Knox¹

2015

VMRR

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Induction of ovulation for controlled breeding is available for use around the world, and conditions for practical application appear promising. Many of the hormones available, such as human chorionic gonadotropin (hCG), gonadotropin-releasing hormone (GnRH) and its analogs, as well as porcine luteinizing hormone (pLH), have been shown to be effective for advancing or synchronizing ovulation in gilts and weaned sows. Each of the hormones has unique attributes with respect to the physiology of its actions, how it is administered, its efficacy, and approval for use. The timing for induction of ovulation during the follicle phase is critical as follicle maturity changes over time, and the success of the response is determined by the stage of follicle development. Female fertility is also a primary factor affecting the success of ovulation induction and fixed time insemination protocols. Approximately 80%–90% of female pigs will develop mature follicles following weaning in sows and synchronization of estrus in gilts. However, those gilts and sows with follicles that are less developed and mature, or those that develop with abnormalities, will not respond to an ovulatory surge of LH. To address this problem, some protocols induce follicle development in all females, which can improve the overall reliability of the ovulation response. Control of ovulation is practical for use with fixed time artificial insemination and should prove highly advantageous for low-dose and single-service artificial insemination and for use with frozen-thawed and sex-sorted sperm.

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Section: Control Of Gnrh Releasementioning

confidence: 99%

Recent advancements in the hormonal stimulation of ovulation in swine

Knox¹

2015

VMRR

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“…Assisted reproductive technology (ART) consisting in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI) and intrauterine insemination (IUI) are based on the exact timing of ovulation, oocyte pick-up before ovulation and then insemination of oocyte ( 2 ). Due to biological activity of human chorionic gonadotropin (hCG) similar to LH, since the mid-1970s exogenous hCG has been used to trigger the final oocyte maturation.…”

Section: Introductionmentioning

confidence: 99%

“…Due to biological activity of human chorionic gonadotropin (hCG) similar to LH, since the mid-1970s exogenous hCG has been used to trigger the final oocyte maturation. The release of oocyte occurs usually 36-40 hours after induction of ovulation similar to natural ovulation ( 2 , 3 ).…”

Section: Introductionmentioning

confidence: 99%

GnRH agonist trigger versus hCG trigger in GnRH antagonist in IVF/ICSI cycles: A review article

Alyasin

Mehdinejadiani

Ghasemi

2016

IJRM

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Routinely, a bolus of 5.000-10.000 IU human chorionic gonadotropin (hCG) is used for the final follicular maturation and ovulation as a standard method. HCG has the same effect of luteinizing hormone (LH) with long half-life. It has the long lutheotrophic effect which increases the risk of ovarian hyper stimulation syndrome (OHSS). Recently, gonadotropin-releasing hormone agonist (GnRH-a) trigger has been used for the induction of final follicular maturation and ovulation with the aim of reducing the OHSS risk. Several studies have shown that the releases of endogenous follicular stimulating hormone (FSH) and LH after administration of GnRH agonist in in vitro fertilization (IVF) cycles are able to precede the final follicular maturation leading to removal of fertile oocyte with normal development of the embryo and ultimately pregnancy. But based on the results of some studies, using GnRH-a trigger leads to defect luteal-phase resulting to reduce the implantation and clinical pregnancy rates and also increase abortion in fresh embryo transfer cycles compared to routine IVF cycle with hCG triggering . Also, in recent years, studies have continued to modify the luteal phase support, so that the fresh embryo transfer is possible too. In this review, we examined the benefits, problems, and also ways to reform GnRH agonist triggering complications.

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“…Although a single bolus of hCG at midcycle has been the gold standard for triggering fi nal oocyte maturation and ovulation in ART cycles, it seems that the GnRH agonist trigger may allow a more physiological surge of both luteinzing hormone (LH) and FSH. Th e short duration of the LH surge with the GnRH agonist trigger of approximately thirty-four hours has been shown to be benefi cial for preventing OHSS in GnRH antagonist IVF cycles, when compared with the prolonged elevation of hCG (≥6 days) after exposure to an hCG bolus 12 . Although an advantage of the GnRH agonist trigger is the ability to retrieve oocytes in high responders with a markedly reduced risk of OHSS, the induction of early luteolysis after the GnRH agonist trigger represents a problem that requires the use of aggressive steroidal luteal support or low-dose hCG to allow successful fresh embryo transfer (ET) and live birth.…”

Section: Gnrh Agonistsmentioning

confidence: 99%

“…Furthermore, there was no evidence indicating that minimal stimulation regimens diff ered signifi cantly from gonadotropins in GnRH agonist protocols in terms of OHSS incidence and live births or pregnancy rates. According to fi ndings from a Cochrane analysis, the use of CC with gonadotropins (with or without mid-cycle antagonist) led to a reduction in the incidence of OHSS varying between 0.8% and 1.8%, compared with 3.5% preva- Casper et al 12 Engmann et al 14 Gülekli et al 16 Humaidan et al 21 Griesenger et al 22 Fatemi et al 45 Tang et al 47 Leitao et al 48 Youssef et al 49 Alvarez et al 50 Busso et al 51 Baumgarten et al Nastri et al 8 Zarek et al 55 Rinaldi et al 56 Casano et al 57 Gibrel et al 58 Figueiredo et al 59 Mild ovarian response Less drug use and lower cost Lower incidence of OHSS Satisfactory pregnancy rates and pregnancy outcome…”

Section: Mild Stimulation Protocolsmentioning

confidence: 99%

Current Medical Strategies in the Prevention of Ovarian Hyperstimulation Syndrome

Kasum

Orešković

Franulić

et al. 2017

acc

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SUMMARY -Th e purpose of this review is to analyze current medical strategies in the prevention of ovarian hyperstimulation syndrome (OHSS) during ovarian stimulation for in vitro fertilization. Owing to contemporary preventive measures of OHSS, the incidence of moderate and severe forms of the syndrome varies between 0.18% and 1.40%. Although none of medical strategies is completely eff ective, there is high-quality evidence that replacing human chorionic gonadotropin (hCG) by gonadotropin-releasing hormone (GnRH) agonists after GnRH antagonists and moderate-quality evidence that GnRH antagonist protocols, dopamine agonists and mild protocols reduce the occurrence of OHSS. Among various GnRH agonists, buserelin 0.5 mg, triptorelin 0.2 mg and leuprolide acetate (0.5-4 mg) have been mostly utilized. Although GnRH trigger is currently regarded as the best tool for OHSS prevention, intensive luteal support with exogenous administration of estradiol and progesterone or low-dose hCG on the day of oocyte retrieval or on the day of GnRH agonist trigger are required to achieve optimal conception rates due to early luteolysis. Among currently available dopamine agonists, cabergoline, quinagolide and bromocriptine are the most common drugs that should be used for prevention of both early and late OHSS. Mild stimulation protocols off er attractive option in OHSS prevention with satisfactory pregnancy rates.

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Basic understanding of gonadotropin-releasing hormone–agonist triggering

Cited by 44 publications

References 17 publications

Recent advancements in the hormonal stimulation of ovulation in swine

Recent advancements in the hormonal stimulation of ovulation in swine

GnRH agonist trigger versus hCG trigger in GnRH antagonist in IVF/ICSI cycles: A review article

Current Medical Strategies in the Prevention of Ovarian Hyperstimulation Syndrome

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