Natural cycle- in vitro fertilization (NC-IVF) is particularly recommended for women with decreased ovarian reserve (DOR) or poor response to controlled ovarian hyperstimulation. In these cases, it can be challenging to determine the optimal timing for a trigger, and follicles of varying sizes are typically obtained. The influence of follicular size on IVF outcomes in women with DOR remains uncertain. This study aims to investigate the association between different follicular sizes and NC-IVF outcomes in women with DOR.A retrospective cohort study involving 477 NC-IVF cycles from 2015 to 2021 was conducted at one of the largest reproductive medical centers in China. Follicular growth was monitored using transvaginal ultrasonography, and the follicles were categorized into three groups based on their diameters:12-15 mm; 16-17 mm and ≥ 18 mm. Laboratory outcomes were evaluated, including the number of canceled cycles, number of oocytes retrieved, 2PN fertilization, embryo and good-quality embryo, fresh embryo transfers, and frozen embryo. Additionally, clinical outcomes, such as the rates of biochemical pregnancy, clinical pregnancy, ongoing pregnancy, and live birth, were investigated and compared among the different follicular size groups.A total of 68 cycles with follicles sizes of 12-15 mm, 171 cycles with follicles sizes of 16-17 mm, and 236 cycles with follicles sizes ≥ 18 mm were included in this study. The basic characteristics, including female age, male age, infertility duration, infertility type, and parity, were comparable among the groups. The rate of cycle cancellation in the 12-15 mm group (27.9%) was higher compared to the other two groups. The 2PN fertilization rate for follicles with a diameter of 16-17 mm (75.0%) was higher than that of follicles with a diameter of 12-15 mm (61.3%) and ≥ 18 mm (56.6%) (P = 0.031). Other clinical outcomes, such as the number of oocytes retrieved, good-quality embryos, fresh embryo transfers, and frozen embryos, did not show significant differences between groups. Further analysis revealed no significant difference in the rates of clinical pregnancy, ongoing pregnancy, and live birth rate among the three groups.This study indicates that in women with DOR undergoing NC-IVF, if a premature LH surge occurs and small follicles are retrieved, these follicles can still be used in subsequent treatment and provide a comparable chance of clinical pregnancy to normal-sized follicles. These findings have important implications for guiding NC-IVF treatment in patients with severe DOR.N/A.© 2023. BioMed Central Ltd., part of Springer Nature.

人绒毛膜促性腺激素（HCG）扳机目的在于促进卵母细胞最后成熟与排卵，此为促排卵中的关键点之一，并与治疗结局密切相关。促排卵周期中HCG的扳机时机主要依赖于对卵泡径线、血中雌孕激素水平和子宫内膜情况等进行综合分析、判断来确定。HCG扳机的药物有HCG制剂和促性腺激素释放激素激动剂（GnRH-a）两种，针对患者和促排卵方案合理选择不同的药物扳机排卵，其对改善助孕结局和降低促排卵并发症有益。

In in vitro fertilization (IVF) cycles, the recommended dose of recombinant human chorionic gonadotropin (r-hCG), for triggering final follicular maturation is 250 μg, although there is some disagreement.

To evaluate the effect of different human chorionic gonadotropin (hCG) doses on the ongoing pregnancy rates in patients with polycystic ovary syndrome (PCOS).Prospective, randomized, controlled trial.Tertiary university referral center.Eighty PCOS patients.Patients were randomized to receive 10,000 IU (n = 28), 5000 IU (n = 26), or 2500 IU (n = 26) of hCG for triggering final oocyte maturation as soon as >or=3 or more follicles of 17 mm or larger were present at ultrasound. Patients were stimulated with recombinant follicle stimulating hormone (FSH) and daily gonadotropin-releasing hormone (GnRH) antagonist, starting on day 6 of stimulation.Ongoing pregnancy, fertilization rates.The median fertilization rates were 52.8%, 65.4%, and 55.6% after administration of 10,000 IU, 5000 IU and 2500 IU, respectively. The ongoing pregnancy rates per PCOS patient receiving hCG were 26.9% (7 of 26), 30.8% (8 of 26) and 34.8% (8 of 23), respectively.A decrease in the dose of hCG used to trigger final oocyte maturation does not appear to affect adversely the probability of pregnancy in PCOS patients treated by IVF using GnRH antagonists and recombinant FSH, and further testing in future larger-scale trials is recommended.

Eliciting an endogenous LH surge by GnRH-agonist for the induction of final oocyte maturation may be more physiological compared with the administration of HCG. However, the efficacy of this intervention in patients treated for IVF with GnRH antagonists remains to be assessed.106 patients were randomized to receive either 10 000 IU urinary HCG or 0.2 mg Triptorelin for triggering final oocyte maturation. Ovarian stimulation for IVF was performed with a fixed dose of 200 IU recombinant FSH and GnRH antagonist was started on stimulation day 6. Luteal phase was supported with micronized vaginal progesterone and oral estradiol. The study was monitored continuously for safety and stopping rules were established.No significant differences were present in the number of cumulus-oocyte complexes retrieved, in the proportion of metaphase II oocytes, in fertilization rates or in the number and quality of the embryos transferred between the two groups. However, a significantly lower probability of ongoing pregnancy in the GnRH agonist arm prompted discontinuation of the trial, according to the stopping rules established (odds ratio 0.11; 95% confidence interval 0.02-0.52).Lower probability of ongoing pregnancy can be expected when GnRH agonist is used for triggering final oocyte maturation instead of HCG in patients undergoing ovarian stimulation for IVF with GnRH antagonists.

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.

To determine the optimal GnRH agonist dose for triggering of oocyte maturation in oocyte donors.Single-center, randomized, parallel, investigator-blinded trial.IVFMD, My Duc Hospital, Ho Chi Minh City, Vietnam.One hundred sixty-five oocyte donors (aged 18-35 years, body mass index [BMI] <28 kg/m(2), antimüllerian hormone level >1.25 ng/mL, and antral follicle count ≥6).Ovulation trigger with 0.2, 0.3, or 0.4 mg triptorelin in a GnRH antagonist cycle.The primary end point was number of metaphase II oocytes. Secondary end points were fertilization and cleavage rates, number of embryos and top-quality embryos, steroid levels, ovarian volume, and ongoing pregnancy rate (PR) in recipients.There were no significant differences between the triptorelin 0.2, 0.3, and 0.4 mg trigger groups with respect to number of metaphase II oocytes (16.0 ± 8.5, 15.9 ± 7.8, and 14.7 ± 8.4, respectively), embryos (13.2 ± 7.8, 11.7 ± 6.9, 11.8 ± 7.0), and number of top-quality embryos (3.8 ± 2.9, 3.6 ± 3.0, 4.1 ± 3.0). Luteinizing hormone levels at 24 hours and 36 hours after trigger was significantly higher with triptorelin 0.4 mg versus 0.2 mg and 0.3 mg (9.8 ± 7.1 IU/L vs. 7.3 ± 4.1 IU/L and 7.2 ± 3.7 IU/L, respectively; 4.6 ± 3.2 IU/L vs. 3.2 ± 2.3 IU/L and 3.3 ± 2.1 IU/L, respectively. Progesterone level at oocyte pick-up +6 days was significantly higher in the 0.4-mg group (2.2 ± 3.7 ng/ml) versus 0.2 mg (1.1 ± 1.0 ng/ml) and 0.3 mg (1.2 ± 1.6 ng/ml). One patient developed early-onset severe ovarian hyperstimulation syndrome (OHSS).No significant differences between triptorelin doses of 0.2, 0.3, and 0.4 mg used for ovulation trigger in oocyte donors were seen with regard to the number of mature oocytes and top-quality embryos.NCT02208986.Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Kisspeptin and neurokinin B (NKB) play a key role in several physiological processes including in puberty, adult reproductive function including the menstrual cycle, as well as mediating the symptoms of menopause. Infundibular kisspeptin neurons, which coexpress NKB, regulate the activity of gonadotropin-releasing hormone (GnRH) neurons and thus the physiological pulsatile secretion of GnRH from the hypothalamus. Outside of their hypothalamic reproductive roles, these peptides are implicated in several physiological functions including sexual behavior and attraction, placental function, and bone health. Over the last two decades, research findings have considerably enhanced our understanding of the physiological regulation of the hypothalamic-pituitary-gonadal (HPG) axis and identified potential therapeutic applications. For example, recognition of the role of kisspeptin as the natural inductor of ovulation has led to research investigating its use as a safer, more physiological trigger of oocyte maturation in in vitro fertilization (IVF) treatment. Moreover, the key role of NKB in the pathophysiology of menopausal hot flashes has led to the development of pharmacological antagonism of this pathway. Indeed, fezolinetant, a neurokinin 3 receptor antagonist, has recently received Food and Drug Administration (FDA) approval for clinical use to treat menopausal vasomotor symptoms. Here, we discuss the roles of kisspeptin and NKB in human physiology, including in the regulation of puberty, menstrual cyclicity, reproductive behavior, pregnancy, menopause, and bone homeostasis. We describe how perturbations of these key physiological processes can result in disease states and consider how kisspeptin and NKB could be exploited diagnostically as well as therapeutically to treat reproductive disorders.

To explore whether prolonged hCG-ovum pickup interval improves assisted reproductive technology outcomes.