Too much of a good thing? Experimental evidence suggests prolonged exposure to hCG is detrimental to endometrial receptivity

Network meta-analysis of four common immunomodulatory therapies for the treatment of patients with thin endometrium

OBEJECTIVE

To compare the effectiveness of endometrial receptivity and pregnancy outcomes of four common immunomodulatory therapies for patients with thin endometrium.

METHOD

This systematic review and network meta-analysis using a literature search up to January 2024, to identify relevant trials comparing endometrial receptivity and pregnancy outcomes of human chorionic gonadotropin (hCG), platelet-rich plasma (PRP), infusion of granulocyte colony-stimulating factor (IG-CSF), and peripheral blood mononuclear cell (PBMC) for patients with thin endometrium. We used surface under the cumulative ranking (SUCRA) to ranked four common immunomodulatory therapies on endometrium thickness, implantation rate (IR), clinical pregnancy rate (CPR), and live birth rate (LBR). RoB2 and ROBINS-I were used to assess the certainty of evidence.

RESULTS

The pooled results of 22 studies showed that hCG (mean difference [MD]: 3.05, 95% confidence interval [CI]: 1.46-4.64) and PRP (MD: 0.98, 95% CI: 0.20-1.76) significantly increase endometrium thickness. The hCG was the best among the IG-CSF (MD = -2.56, 95% CI = -4.30 to -0.82), PBMC (MD = -2.75, 95% CI = -5.49 to -0.01), and PRP (MD = -2.07, 95% CI = -3.84 to -0.30) in increasing endometrium thickness. However, IG-CSF and PRP significantly improved IR (IG-CSF: risk ratio (RR; IG-CSF: RR = 1.33, 95% CI = 1.06-1.67; PRP: RR = 1.63, 95% CI = 1.19-2.23), and LBR (IG-CSF: RR = 1.53, 95% CI = 1.16-2.02; PRP: RR = 1.59, 95% CI = 1.08-2.36).

CONCLUSIONS

Available evidence reveals that hCG and subcutaneous or intrauterine CSF (SG-CSF) may be the best treatment options for current thin endometrium patients. However, future high-quality and large-scale studies are necessary to validate our findings.

Intrauterine instillation of human chorionic gonadotropin at the time of blastocyst transfer: Systematic review and meta-analysis

Intrauterine instillation (IU) of Human Chorionic Gonadotropin (hCG) before embryo transfer (ET) has been proposed to enhance implantation success rates. This is the first meta-analysis to evaluate the effect at the blastocyst-stage. A systematic literature search was performed using Medline, Embase, Cochrane Library and Google. Randomized clinical trials (RCTs) were included. The primary outcome combined live birth rate (LBR) and ongoing pregnancy rate (OPR). The secondary outcomes were clinical pregnancy rate (CPR), implantation rate (IR) and miscarriage rate (MR). 93 citations were identified, of which there were seven eligible RCTs. 2499 participants were included in the meta-analysis; 1331 were assigned to an experimental group and 1168 were assigned to the control group. The overall effect of IU hCG instillation on LBR and OPR was not significant: risk ratio (RR) 1.00 (95% CI, 0.90-1.12). Analysis of secondary outcomes found the effect of IU hCG instillation was not significant. Analysis of the data suggests that the studies conducted have too much heterogeneity to identify whether a specific cohort may have a significant benefit. The findings of this meta-analysis demonstrate that there is insufficient evidence at present to support the use of IU hCG instillation prior to blastocyst-stage ET.

Endometrial Receptivity During the Preimplantation Period: A Narrative Review

Endometrial receptivity is a complex and critical process fundamental to achieving a successful pregnancy. While researchers have made significant strides in understanding the underlying mechanisms governing endometrial receptivity, effective diagnostic and therapeutic strategies remain scarce. This review article aims to elucidate the various factors that contribute to endometrial receptivity, including the hormonal regulation and molecular mechanisms that govern this process, as well as potential biomarkers for assessing endometrial receptivity. One of the major challenges in identifying reliable biomarkers for endometrial receptivity is the intricate nature of the process itself. Nonetheless, recent advances in transcriptomic and proteomic technologies have identified several candidate biomarkers that could potentially enhance our ability to predict endometrial receptivity. Furthermore, emerging technologies such as single-cell RNA sequencing and mass spectrometry-based proteomics hold great promise for providing novel insights into the molecular mechanisms underlying endometrial receptivity. Despite the lack of reliable biomarkers, various therapeutic strategies have been proposed to improve endometrial receptivity. One promising approach involves the transplantation of mesenchymal stem cells (MSCs), which have been shown to increase endometrial thickness and receptivity in both animal models and clinical trials. Growth factors, cytokines, and exosomes derived from MSCs and other cell types may also have therapeutic potential for addressing endometrial dysfunction.

Efficacy of intrauterine infusion therapy before embryo transfer in recurrent implantation failure: A systematic review and network meta-analysis

Previous studies of intrauterine infusion therapy in recurrent implantation failure (RIF) patients have shown conflicting results, and there is a lack of head-to-head horizontal comparisons between different drugs. This study aimed to assess the effectiveness of four intrauterine infusion drugs, including human chorionic gonadotropin (HCG), granulocyte colony-stimulating factor (G-CSF), peripheral blood mononuclear cells (PBMCs) and autologous platelet-rich plasma (PRP), in improving pregnancy outcomes in RIF patients through the network meta-analysis. Randomized controlled trials (RCTs) of preimplantation intrauterine infusion for RIF were searched in the Cochrane Library, Embase, Medline and CINAHL. Meanwhile, relevant data were extracted and Stata 15.0 software was applied to statistical analysis. A total of 21 studies with a sample size of 2917 cases were included in this study. Clinical pregnancy rate network meta-analysis showed that, intrauterine infusion of all four drugs is significantly better than the blank and placebo groups, while only PRP could significantly increase live birth rate compared with the blank and placebo groups. The SUCRA plots of clinical pregnancy and live birth rates showed a higher ranking of PRP and PBMCs. Early abortion intervention analysis found that only G-CSF is significantly better than the blank and placebo groups, and the SUCRA plot of G-CSF showed the highest ranking. All these findings confirmed that all four intrauterine infusion drugs can improve pregnancy outcomes in RIF patients to varying degrees, with PRP being the most effective. Further prospective, large-scale and high-quality RCTs are still necessary to determine the exact subgroups of benefit for the different drugs.

Triggering with 1,500 IU of human chorionic gonadotropin plus follicle-stimulating hormone compared to a standard human chorionic gonadotropin trigger dose for oocyte competence in in vitro fertilization cycles: a randomized, double-blinded, controlled noninferiority trial

OBJECTIVE

To assess if triggering with 1,500 IU of human chorionic gonadotropin (hCG) with 450 IU of follicle-stimulating hormone (FSH) induces noninferior oocyte competence to a standard dose of hCG trigger used in in vitro fertilization (IVF). The alternative trigger will be considered noninferior if it is at least 80% effective in promoting oocyte competence.

DESIGN

Randomized, double-blinded, controlled noninferiority trial.

SETTING

Academic infertility practice.

PATIENTS

Women aged 18-41 undergoing IVF with antral follicle count ≥8, body mass index ≤30 kg/m², and no history of ≥2 IVF cycles canceled for poor response were enrolled. Participants with a serum estradiol >5,000 pg/mL on the day of trigger were excluded because of high risk of ovarian hyperstimulation syndrome.

INTERVENTIONS

Participants were randomized to receive an alternative trigger of 1,500 IU of hCG plus 450 IU of FSH or a standard trigger dose of hCG (5,000 or 10,000 IU) for final oocyte maturation.

MAIN OUTCOME MEASURES

The primary outcome was total competent proportion, defined as the probability of 2 pronuclei from an oocyte retrieved. The alternative trigger will be considered noninferior to the standard trigger if a 1-sided 95% confidence interval (CI) of the relative risk (RR) is not <0.8. Secondary outcomes included oocyte recovery and maturity, intracytoplasmic sperm injection fertilization, embryo quality, pregnancy rates, as well as serum and follicular hormones. Secondary outcomes were compared using a 2-sided superiority test. Outcomes were analyzed by intention-to-treat and per-protocol.

RESULTS

A total of 105 women undergoing IVF were randomized from May 2015 to June 2018. The probability of the primary outcome was 0.59 with the alternative trigger and 0.65 with the standard trigger, with a RR of 0.91 and a 1-sided 95% CI of 0.83. Noninferiority of the alternative trigger was demonstrated. Live birthrate from all fresh transfers in the alternative trigger group vs. standard trigger was 46.9 vs. 46.4% (RR, 1.01; 95% CI, 0.62-1.62), respectively. Live birthrate per randomized participant was 48.1% in the alternative trigger group vs. 62.7% with the standard trigger (RR, 0.73; 95% CI, 0.48-1.11). No participants had a failed retrieval.

CONCLUSION

Triggering with 1,500 IU of hCG plus 450 IU of FSH promoted noninferior oocyte competence compared to a standard hCG trigger dose.

TRIAL REGISTRATION

NCT02310919.

Expression and function of the luteinizing hormone choriogonadotropin receptor in human endometrial stromal cells

The human luteinising hormone choriogonadotropin receptor (LHCGR) is a G-protein coupled receptor activated by both human chorionic gonadotropin (hCG) and luteinizing hormone (LH), two structurally related gonadotropins with essential roles in ovulation and maintenance of the corpus luteum. LHCGR expression predominates in ovarian tissues where it elicits functional responses through cyclic adenosine mononucleotide (cAMP), Ca²⁺ and extracellular signal-regulated kinase (ERK) signalling. LHCGR expression has also been localized to the human endometrium, with purported roles in decidualization and implantation. However, these observations are contentious. In this investigation, transcripts encoding LHCGR were undetectable in bulk RNA sequencing datasets from whole cycling endometrial tissue and cultured human endometrial stromal cells (EnSC). However, analysis of single-cell RNA sequencing data revealed cell-to-cell transcriptional heterogeneity, and we identified a small subpopulation of stromal cells with detectable LHCGR transcripts. In HEK-293 cells expressing recombinant LHCGR, both hCG and LH elicited robust cAMP, Ca²⁺ and ERK signals that were absent in wild-type HEK-293 cells. However, none of these responses were recapitulated in primary EnSC cultures. In addition, proliferation, viability and decidual transformation of EnSC were refractory to both hCG and LH, irrespective of treatment to induce differentiation. Although we challenge the assertion that LHCGR is expressed at a functionally active level in the human endometrium, the discovery of a discrete subpopulation of EnSC that express LHCGR transcripts may plausibly account for the conflicting evidence in the literature.

Evolution of serum progesterone levels in the very early luteal phase of stimulated IVF/ICSI cycles post hCG trigger: a proof of concept study

BACKGROUND

Studies have suggested that controlled ovarian hyperstimulation adversely affects endometrial receptivity due to advanced endometrial maturation. This adverse effect is mainly attributed to supraphysiological levels of both estrogen and progesterone identified in stimulated cycles. There is a paucity of published data investigating the very early luteal steroid profile following hCG trigger.

AIM OF THE STUDY

This prospective, observational study was undertaken to determine the increase in serum progesterone levels after human chorionic gonadotrophin (hCG) trigger in stimulated IVF/ICSI cycles.

MATERIALS AND METHODS

This proof-of-concept study included 11 patients requiring ovarian stimulation for IVF/ICSI and who planned to avail of pre-implantation genetic screening with embryo vitrification of their biopsied embryos at blastocyst stage. For each study participant, five additional blood samples were drawn at the following specific times in the stimulation cycle, on the morning (10.00-12.00) of the assigned day to induce final oocyte maturation with hCG trigger, immediately prior to administration of hCG for final oocyte maturation, 1 h, 2 h, and 36 h post hCG trigger. A prediction model, the Gompertz curve, was used to determine serum progesterone levels at intervals between the 2 h post hCG trigger sample and the day of oocyte retrieval.

RESULTS

Statistically significant increases in serum progesterone levels were identified following hCG administration as early as 1 h following trigger (P4 0.57 ng/ml, p < 0.05), 2 h following trigger (P4 0.88 ng/ml, p < 0.001) and on the day of oocyte retrieval (P4 9.68 ng/ml, p < 0.001). According to our prediction model, the Gompertz curve, the projected serum progesterone level at 4 h post trigger would have achieved a level of 1.45 ng/ml, 8 h post trigger of 3.04 ng/ml, and 12 h post trigger of 4.8 ng/ml. The very early and significant increases in serum progesterone following hCG trigger are clearly demonstrated in this study.

CONCLUSION

The endometrium is undoubtedly exposed to rapidly increasing serum progesterone levels post hCG trigger that would not be identified until much later in natural menstrual cycles.

TRIAL REGISTRATION NUMBER

This study is registered with clinicaltrials.gov under the identifier NCT04417569.

Is Human Chorionic Gonadotropin Trigger Beneficial for Natural Cycle Frozen-Thawed Embryo Transfer?

Objective: The aim of this study is to investigate, in ovulatory patients, whether there is a difference in reproductive outcomes following frozen-thawed embryo transfer (FET) in natural cycles (NC) compared to modified natural cycles (mNC).

Methods: This retrospective cohort study, performed at the public tertiary fertility clinic, involved all infertile patients undergoing endometrial preparation prior to FET in NC and mNC from January, 2017 to November, 2020. One thousand hundred and sixty-two patients were divided into two groups: mNC group (n = 248) had FET in a NC after ovulation triggering with human chorionic gonadotropin (hCG); NC group (n = 914) had FET in a NC after spontaneous ovulation were observed. The primary outcome was live birth rate. All pregnancy outcomes were analyzed by propensity score matching (PSM) and multivariable logistic regression analyses.

Results: The NC group showed a higher live birth rate [344/914 (37.6%) vs. 68/248 (27.4%), P = 0.003; 87/240 (36.3%) vs. 66/240 (27.5%), P = 0.040] than the mNC group before and after PSM analysis. Multivariable analysis also showed mNC to be associated with a decreased likelihood of live birth compared with NC [odds ratio (OR) 95% confidence interval (CI) 0.71 (0.51–0.98), P = 0.039].

Conclusion: For women with regular menstrual cycles, NC-FET may have a higher chance of live birth than that in the mNC-FET cycles. As a consequence, it's critical to avoid hCG triggering as much as possible when FETs utilize a natural cycle strategy for endometrial preparation. Nevertheless, further more well-designed randomized clinical trials are still needed to determine this finding.

A microenvironment of high lactate and low pH created by the blastocyst promotes endometrial receptivity and implantation

RESEARCH QUESTION

Is the blastocyst's idiosyncratic metabolic production of lactate, and creation of a specialized microenvironment at the implatation site, an important mediator of maternal-fetal signalling to promote endometrial receptivity and implantation?

DESIGN

Hormonally primed ECC-1 and Ishikawa cells were used to assess functional changes to the endometrial epithelium after exposure to lactic acid (LA), LA with neutralized pH (nLA) or acidic pH (pH_L). Tight junction integrity (transepithelial resistance [TER]), cellular proliferation or changes to gene expression by RT-PCR were analysed. The effect of LA on Endometrial stromal cells decidualization and migratory capacity, and HUVEC endothelial tube formation and angiogenesis, were also assessed.

RESULTS

Treatment of ECC-1 cells with 2.5 mM (P = 0.0037), 5 mM (P = 0.0044), 7.5 mM and 10 mM (P = 0.003) (P = 0.0021) LA significantly decreased the rate of cellular proliferation while TER was decreased with exposure to 2.5 mM LA (P = 0.024), 5 mM LA (P = 0.021) and 7.5 mM LA (P = 0.033). Exposure to nLA or pH_L had no effect on proliferation or TER. Upregulation of GLUT4 (P = 0.002), GPR81 (P = 0.048), VEGF, SNAI1 (both P < 0.001) and RELA (P = 0.023) mRNA expression was observed after exposure of Ishikawa cells to combined LA plus pH_L. Lactic acid increased the migratory capacity of decidualized stromal cells (P = 0.047) without changing the extent of decidualization. HUVEC tube formation was significantly increased by 5 mM LA exposure (P = 0.009).

CONCLUSIONS

The identification of LA as an important mediator in the maternal-fetal dialogue underpinning implantation is supported. Further examination of the role of LA within the infertile or compromised endometrium could improve natural and assisted pregnancy success and needs further investigation.

Superovulation with human chorionic gonadotropin (hCG) trigger and gonadotropin releasing hormone agonist (GnRHa) trigger differentially alter essential angiogenic factors in the endometrium in a mouse ART model†

Gonadotropin-releasing hormone agonists (GnRHa) are used as an alternative to human chorionic gonadotropin (hCG) to trigger ovulation and decrease the risk of ovarian hyperstimulation syndrome. GnRHa is less potent at inducing ovarian vascular endothelial growth factor (VEGF), but may also affect endometrial angiogenesis and early placental development. In this study, we explore the effect of superovulation on endometrial angiogenesis during critical periods of gestation in a mouse model. We assigned female mice to three groups: natural mating or mating following injection with equine chorionic gonadotropin and trigger with GnRHa or hCG trigger. Females were killed prior to implantation (E3.5), post-implantation (E7.5), and at midgestation (E10.5), and maternal serum, uterus, and ovaries were collected. During peri-implantation, endometrial Vegfr1 and Vegfr2 mRNA were significantly increased in the GnRHa trigger group (P < 0.02) relative to the hCG group. Vegfr1 is highly expressed in the endometrial lining and secretory glands immediately prior to implantation. At E7.5, the ectoplacental cone expression of Vegfa and its receptor, Vegfr2, was significantly higher in the hCG trigger group compared to the GnRHa group (P < 0.05). Soluble VEGFR1 and free VEGFA were much higher in the serum of mice exposed to the hCG trigger compared to GnRHa group. At midgestation, there was significantly more local Vegfa expression in the placenta of mice triggered with hCG. GnRHa and hCG triggers differentially disrupt the endometrial expression of key angiogenic factors during critical periods of mouse gestation. These results may have significant implications for placental development and neonatal outcomes following human in vitro fertilization.

Intrauterine administration of peripheral blood mononuclear cells activated by human chorionic gonadotropin in patients with repeated implantation failure: A meta-analysis

The purpose of this study was to assess whether intrauterine administration of peripheral blood mononuclear cells (PBMCs) activated by human chorionic gonadotropin (hCG) could improve the pregnancy and live birth rates in women with repeated implantation failure (RIF), and whether the parameters of co-culture of hCG and PBMCs would affect the clinical outcomes. Six databases (PubMed, Ovid, Medline, NCBI, Cqvip and Wanfang) were searched up to October 2020 by two independent reviewers. Seven studies were included according to specific inclusion and exclusion criteria. A meta-analysis showed that the pregnancy and live birth rates were significantly increased in the case group compared with the control group (odds ratio [OR]: 3.43, 95 % confidence interval [CI]: 1.78-6.61; P =  0.0002 and OR: 2.79, 95 % CI: 1.09-7.15; P =  0.03), especially when hCG was cultured with PBMCs for 48 h or PBMCs administration was performed two or three days before embryo transfer (ET). Neither the dosage of the hCG co-cultured with PBMCs nor the mean concentration of the administered PBMCs appeared to influence the therapeutic efficiency. In conclusion, intrauterine administration of PBMCs co-cultured with hCG for 48 h, conducted two or three days before ET, could be an effective therapy for women experiencing RIF. Due to the limitations of sample size and quality of the included studies, further high-quality studies with large sample sizes are warranted to optimize the parameters of hCG and PBMC co-culture to help more RIF patients benefit from this therapy.

Embryo Morphokinetics and Blastocyst Development After GnRH Agonist versus hCG Triggering in Normo-ovulatory Women: a Secondary Analysis of a Multicenter Randomized Controlled Trial

Gonadotropin-releasing hormone agonist (GnRHa) for final oocyte maturation, along with vitrification of all usable embryos followed by transfer in a subsequent frozen-thawed cycle, is the most effective strategy to avoid ovarian hyperstimulation syndrome (OHSS). However, less is known about the ovulation induction triggers effect on early embryo development and blastocyst formation. This study is a secondary analysis of a multicenter, randomized controlled trial, with the aim to compare embryo development in normo-ovulatory women, randomized to GnRHa or human chorionic gonadotropin (hCG) trigger. In all, 4056 retrieved oocytes were observed, 1998 from the GnRHa group (216 women) and 2058 from the hCG group (218 women). A number of retrieved oocytes, mature and fertilized oocytes, and high-quality embryos and blastocysts were similar between the groups. A sub-analysis in 250 women enrolled at the main trial site including 2073 oocytes was conducted to compare embryo morphokinetics and cleavage patterns with EmbryoScope time-lapse system. In total, 1013 oocytes were retrieved from the GnRHa group (124 women) and 1060 oocytes were retrieved from the hCG group (126 women). Morphokinetic parameters and cleavage patterns were comparable between the groups. However, embryos derived from the GnRHa group were less likely to perform rolling during their development than the embryos from the hCG trigger group (OR = 0.41 (95%CI 0.25; 0.67), p-value 0.0003). The comparable results on embryo development and utilization rates between the GnRHa and hCG triggers is of clinical relevance to professionals and infertile patients, when GnRHa trigger and freeze-all is performed to avoid OHSS development. ClinicalTrials.gov Identifier: NCT02746562.

[Timing of HMG supplementation and clinical outcomes of advanced-age patients with diminished ovarian reserve receiving gonadotropin-releasing hormone antagonist protocol]

OBJECTIVE

To assess the effect and timing of human menopausal gonadotropin (HMG) supplementation in advancedage patients with diminished ovarian reserve (DOR) receiving gonadotropin-releasing hormone antagonist protocol.

OBJECTIVE

A total of 682 patients with DOR aged over 35 years undergoing IVF-ET treatment were included in this study. All the patients underwent a GnRH antagonist protocol, and controlled ovarian stimulation was initiated on day 2-3 of the menstrual cycle with follicle stimulation hormone (FSH). According to the timing of HMG supplementation, the patients were divided into no supplementation group (n=371) without HMG supplementation; early supplementation group (n=139), in which daily HMG supplementation started on the first day till the trigger day; and late supplementation group (n=172), in which HMG supplementation started when the leading follicle reached 10-14 mm in diameter and lasted until the trigger day. The pregnancy outcomes of the patients were compared among the 3 groups.

OBJECTIVE

The 3 groups showed no significant difference in hCG trigger day E2 and P levels, endometrial thickness, or the number of follicles with comparable fertilization rate and cleavage rate (P>0.05). Gn dose used was the lowest in no supplementation group, and the average number of oocytes retrieved was significantly smaller in early supplementation group than in late supplementation group (P < 0.05). The mean number of mature oocytes and embryos available were significantly higher in late supplementation group than in early supplementation group (P < 0.05). The clinical pregnancy rate of fresh embryo transfer cycle was significantly higher in late supplementation group than in no supplementation group (27.7% vs 45.1%, P < 0.05), but the implantation rate, early miscarriage rate, heterotopic pregnancy rate and live birth rate were comparable among the 3 groups (P>0.05). No significant differences were found among the 3 groups in the implantation rate, clinical pregnancy rate, early miscarriage rate, heterotopic pregnancy rate or live birth rate of the first frozen-thawed embryo transfer cycle with a freeze-all strategy (P>0.05).

OBJECTIVE

HMG supplementation in the middle and late follicular phase can improve the outcomes of controlled ovarian hyperstimulation and increase the clinical pregnancy rate of fresh embryo transfer cycle in advanced-age patients with DOR undergoing GnRH antagonist protocol.

Approaches to Improve Endometrial Receptivity in Case of Repeated Implantation Failures

Repeated implantation failures are a constant challenge in reproductive medicine with a significant impact both on health providers and on infertile couples. Several approaches have been proposed so far as effective; however, accumulative data have clarified that most of the treatment options do not have the evidence base for a generalized application to be suggested by the relevant societies. Implantation failures are attributed to either poor quality embryos or to defected endometrial receptivity. The current review aims to summarize in a systematic way all the new trends in managing RIF via interference with endometrial receptivity. The authors focus mainly, but not exclusively, on endometrial injury prior to embryo transfer and endometrial priming with autologous cells or biological agents. To this direction, a systematic search of the Pubmed database has been conducted taking into account the emerged evidence of the last two decades. All the suggested interventions are herein presented and analyzed in terms of reproductive outcomes. It is evident that properly powered and designed randomized trials are needed to support a new standard approach in RIF treatment that will safely be incorporated in national and international guidelines.

Efficacy of intrauterine perfusion of peripheral blood mononuclear cells (PBMC) for infertile women before embryo transfer: meta-analysis

This meta-analysis was intended to evaluate the effects of intrauterine perfusion of peripheral blood mononuclear cells (PBMC) on the pregnancy outcomes including clinical pregnancy rates, embryo implantation rates, live birth rates and miscarriage rates of infertile women who were undergoing in vitro fertilisation (IVF) treatment. By searching Pubmed, Embase database, five articles meeting the inclusion criteria were included, and 1173 women were enrolled (intrauterine PBMC group: n = 514; NO-PBMC group: n = 659). For the entire IVF/ICSI population and one or two embryo transfer failure patients, there was no significant difference in endometrial thickness, embryo implantation rates, live birth rates, and miscarriage rates between the PBMC group and NO-PBMC group. Although the clinical pregnancy rates of the PBMC group were higher than that of the NO-PBMC group, the confidence interval was close to the line of unity. As for the patients with three or more implantation failures, the clinical pregnancy rates, embryo implantation rates and live birth rates were much higher in the PBMC group than that of the NO-PBMC group. In summary, current evidence suggests that intrauterine perfusion of PBMC can significantly improve pregnancy outcomes in patients who have three or more implantation failures.Impact statementWhat is already known on this subject? An increasing number of studies have shown that immune cells play an important role in embryo transfer. There is no reliable evidence to confirm the clinical efficacy of intrauterine perfusion of PBMC.What do the results of this study add? The current evidence suggests that intrauterine perfusion of PBMC can significantly improve pregnancy outcomes in patients who have three or more implantation failures.What are the implications of these findings for clinical practice and/or further research? To the best of our knowledge, this meta-analysis is the first to evaluate the effect of intrauterine perfusion of PBMC on pregnancy outcomes before embryo transfer. Our study indicated that intrauterine perfusion of PBMC significantly increased clinical pregnancy rates, embryo implantation rates, and live birth rates in patients who failed more than three implants.

Effect of HCG-Triggered Ovulation on Pregnancy Outcomes in Intrauterine Insemination: An Analysis of 5,610 First IUI Natural Cycles With Donor Sperm in China

Objective: To evaluate the effect of human chorionic gonadotropin (hCG) trigger ovulation on pregnancy outcomes in natural IUI cycles with donor sperm. Methods: This retrospective cohort study included 5,610 first-natural IUI cycles with donor sperm in infertile couples during the period from January 2012 to December 2017. To control for other confounding factors, our analysis was restricted to normo-ovulatory women without tubal infertility. The main outcome measure was live birth rate; the secondary outcomes included rates of clinical pregnancy and miscarriage. Results: In the crude analysis, both the clinical pregnancy (27.40 vs. 22.73%; P = 0.001) and live birth rates (24.52 vs. 20.13%; P = 0.007) were significantly higher for the hCG group than for the spontaneous LH group. After adjustment for a number of confounding factors, the reproductive outcomes were still significantly worse for the spontaneous ovulatory group. Conclusions: Among women undergoing natural cycle IUI with donor sperm, hCG triggered ovulation for timing insemination offers beneficial impacts on both clinical pregnancy rates and live birth rates.

Intramuscular injection of human chorionic gonadotropin prior to secretory transformation in patients undergoing frozen-thawed embryo transfer cycles

BACKGROUND

The major difference between a natural cycle and an artificially prepared cycle is the lack of luteinizing hormone (LH) peak in the latter. The LH/hCG receptors were identified to express in human endometrium and evidences of experiments also suggested the beneficial role of hCG in embryo implantation, indicating that the LH peak might be of clinical significance and the activation of LH/hCG receptors in the endometrium could improve embryo implantation. Hence, we postulated that the addition of hCG prior to secretory transformation in an artificial cycle might improve pregnancy outcomes.

METHODS

This retrospective cohort study was conducted at a Reproductive Medicine Center between 2016 and 2018. Patients aged ≤43 years at the (index) oocyte retrieval and undergoing artificially prepared frozen-thawed embryo transfer (FET) with at least one good-quality embryo transferred were included. The cycles were divided into two groups: The hCG group (n = 337) received an intramuscular injection of 10,000 IU hCG before secretory transformation; the control group (n = 364) performed FET without hCG administration. The primary endpoint was live birth delivery rate (LBR), secondary outcomes included implantation rate, clinical pregnancy rate (CPR) and ongoing pregnancy rate (OPR).

RESULTS

The LBR (49.9% vs 39.6%, P < 0.01), CPR (61.4% vs 50.5%, P < 0.01) and OPR (52.8% vs 43.1%, P < 0.05) were statistically significantly higher in the hCG group than the control group. The superiority in LBR after hCG administration remained significant after adjusting for confounding factors (OR 1.613, 95% CI 1.173-2.217; P < 0.01). In the subgroup analysis, the improvement in LBR was statistically significant after hCG administration for cleavage-stage embryo transfer cycles (51.2% vs 42.3%, P < 0.05), whereas for blastocyst transfer cycles, the improvement in LBR was not (45.7% vs 31.3%, P > 0.05).

CONCLUSIONS

Intramuscular hCG injection prior to secretory transformation may benefit LBR in patients undergoing artificially prepared FET cycles. But it should be noted that nonsignificant tendency towards higher LBR was observed after hCG administration in patients undergoing blastocyst transfer. So, future prospective randomized controlled studies are required to confirm, especially for blastocyst transfer cycles.

The impact of hyaluronan-enriched culture medium and intrauterine infusion of human chorionic gonadotropin on clinical outcomes in blastocyst transfer cycles

Over the last few decades, advances in ovarian hormonal stimulation, embryology laboratory technologies and embryo genetic testing, have significantly enhanced clinical outcomes in human assisted reproduction technologies (ART). However, embryo implantation remains a major bottleneck in achieving better pregnancy and live birth rates. Thus, there is growing interest in establishing new approaches to enhance implantation efficiency after embryo transfer. With advanced molecular techniques, many promising biomarkers associated with embryonic and endometrial changes occurring prior to and during embryo implantation have been identified. However, despite the progress in applying novel procedures into IVF practice, clinical evaluation of those biomarkers has so far reached modest predictive value for enhancing blastocyst developmental potential and endometrial receptivity. Therefore, other simpler strategies have also been introduced to increase the rates of successful clinical pregnancies and live births. One of these approaches is to investigate the impact of using embryo transfer medium containing high concentrations of an adherence compound, such as hyaluronic acid (HA), on IVF outcomes. Additionally, intrauterine infusion of a small volume of human chorionic gonadotropin (hCG) at the time of embryo transfer (ET) has also been proposed as a technique that might be advantageous for increasing the clinical outcomes, considering the fact that hCG plays a critical role in synchronizing endometrial and fetal development. However, the current findings from both interventions remain controversial, demonstrating a mixture of positive and indifferent results of these treatments in ART cycles. Further research will be crucial for a better understanding of the molecular mechanism of cross-talk between the blastocyst and the maternal endometrium during the optimal implantation period when using either hyaluronan-enriched medium or hCG infusion before embryo transfers. Therefore, this review aims to present existing literature related to both treatments, emphasizing their effects on blastocyst implantation.Abbreviations: ART: assisted reproduction technologies; HA: hyaluronic acid; hCG: human chorionic gonadotrophin; IVF: in vitro Fertilization; ET: embryo transfer; pH: hydrogen ions; CO2: Carbone dioxide; O2: Oxygen; PGT: pre-implantation genetic testing; FET: frozen embryo transfer; PCOS: Polycystic ovarian syndrome; DNA: deoxyribonucleic acid; miRNA: micro-ribonucleic acid; EVs: extracellular vesicles; ERA: endometrial receptivity array; CD44 and RHAMM: primary hyaluronan surface receptors; RCT: randomized clinical trials; LBR: life birth rate; CPR: clinical pregnancy rate; IR: implantation rate.

Endometrial human chorionic gonadotropin (hCG) expression is a marker for adequate secretory transformation of the endometrium

PURPOSE

Successful embryo implantation into the endometrium depends on embryonic characteristics and proper endometrial development. Reproductive medicine often focuses on embryo quality, whereas reliable diagnostic tests for endometrial receptivity are still needed. We previously found that human chorionic gonadotropin (hCG), one of the earliest proteins secreted by the embryo, was also expressed by the luteal phase endometrium around the implantation window. Here, we tested our hypothesis of endometrial hCG as an implantation marker.

METHODS

Endometrial biopsies and serum samples were taken from patients undergoing routine infertility diagnostics. Correlations of immunohistochemically detected endometrial hCG expression with adequate endometrial secretory transformation, the infiltration of CD45-positive leukocytes, clinical diagnostic parameters, and endometrial thickness were analyzed.

RESULTS

A highly significant correlation between the endometrial score, as a measurement for regular secretory transformation, and the intensity of hCG staining was found. The invasion of CD45-positive leukocytes increased with progressing endometrial secretory transformation and rising endometrial hCG expression. In addition, serum progesterone concentrations correlated with hCG expression by the endometrial glands.

CONCLUSIONS

Our results suggest endometrial hCG as a possible diagnostic parameter characterizing the endometrial secretory transformation and, thus, possibly also its implantation capability.

The role of recombinant LH in women with hypo-response to controlled ovarian stimulation: a systematic review and meta-analysis

OBJECTIVE

To study the role of recombinant human LH supplementation in women with hypo-response to ovarian stimulation.

METHODS

We performed a systematic review and meta-analysis of prospective clinical trials in which recombinant FSH monotherapy protocols were compared with LH-supplemented protocols in hypo-responders. A search was conducted of the Scopus, MEDLINE databases without time or language restrictions. Primary outcome was clinical pregnancy rate.

RESULTS

Significantly higher clinical pregnancy rates (odds ratio: 2.03, P = 0.003), implantation rates (odds ratio: 2.62, P = 0.004) and number of oocytes retrieved (weight mean differences: 1.98, P = 0.03) were observed in hypo-responders supplemented with recombinant LH versus hypo-responders who underwent FSH monotherapy. No differences in terms of mature oocytes or miscarriage rates were found between the two groups.

CONCLUSION

In conclusion, our analysis confirms that women with a hypo-response to exogenous gonadotropins might benefit from LH supplementation. However, more trials are required before a definitive conclusion can be drawn.

Intrauterine infusion of human chorionic gonadotropin before embryo transfer in IVF/ET cycle: The critical review

Intrauterine infusion of human chorionic gonadotropin (IUI-hCG) has been proposed to improve the outcome of in vitro fertilization-embryo transfer (IVF-ET), since it plays a critical role in synchronizing endometrial and fetal development. As the early mediator from embryo, hCG promotes the decidualization, angiogenesis, maternal immune tolerance, and trophoblast invasion, favoring successful implantation of embryo. Although multiple clinical trials have been conducted to verify the efficacy of IUI-hCG on IVF-ET outcome in recent years, the findings remained controversial. The difference in study design and population might be the cause to the different consequences after administration of hCG. More importantly, the endometrial receptivity, which might affect the efficacy of IUI-hCG, has not been assessed in women receiving this intervention. Selecting the right population suitable for IUI-hCG based on known etiology would be crucial in enhancing its efficacy and minimize any possible complications. Investigation of optimal indications for IUI-hCG should be highlighted in the future.

Proliferation Profile of Uterine Endometrial Stromal Cells during In Vitro Culture with Gonadotropins: Recombinant versus Urinary Follicle Stimulating Hormone

Background

Provision of optimal endometrial stromal cells is essential in uterine tissue engineering. Culture of these cells is significantly influenced by gonadotropin hormones. This investigation attempted to define the proliferation profiles of murine uterine endometrial stromal cells during in vitro culture with recombinant follicle stimulating hormone (rFSH), urinary follicle stimulating hormone (uFSH), and human chorionic gonadotropin (hCG).

Methods

Murine uterine endometrial stromal cells were collected from 8-week-old mice and cultured in vitro up to 72 h, with rFSH, uFSH, or hCG. Cell cycles were analyzed by BrdU assay, and cyclin D1 expression was evaluated according to dose and duration of gonadotropin treatment.

Results

BrdU assay showed a further inhibitory effect on murine uterine endometrial stromal cell proliferation when cultured with rFSH compared to uFSH, and a similar inhibitory proliferation profile when cultured with hCG at a specific range of concentrations. The expression of cyclin D1 of murine uterine endometrial stromal cells was down-regulated when cultured with rFSH, uFSH, or hCG, compared to control.

Conclusions

FSH may inhibit the proliferation of murine uterine endometrial stromal cells during in vitro culture. rFSH may have more significant inhibitory effects on the proliferation of endometrial stromal cells than uFSH. Establishing an optimal endocrine milieu is necessary using more advanced combination of female hormones for in vitro culture of this type of cells.

Evidence for expression and functionality of FSH and LH/hCG receptors in human endometrium

PURPOSE

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) mediate intracellular functions by binding their specific protein G-coupled gonadotrophin receptor, respectively FSH receptor (FSHR) and LH/choriogonadotrophin receptor (LHCGR). Whereas the expression of FSHR and LHCGR in mammals was considered gonad-specific and cell-specific, studies identified gonadotrophin receptors in human female extragonadal reproductive tissues. This study aims to demonstrate that gonadotrophin receptors are expressed in endometrium and mediates intracellular functions.

METHODS

Collected endometria (n = 12) from healthy patients (mean age of 36 ± 6) were primary cultured for 24 h. The presence of gonadotrophin receptors was evaluated by RT-PCR followed by the sequencing of the resulted amplicons and by immunohistochemistry in original samples. Endometrial primary cultures were treated with increasing concentration (range 0-100 ng/ml) of either recombinant human LH (rhLH) or recombinant human FSH (rhFSH). Endometria controls had gonadotrophin replaced by the same volume of the culture medium. In gonadotrophin-treated samples, it was evaluated the intracellular cyclic adenosine monophosphate (cAMP) content by enzymatic immunoassay and the expression of steroidogenic genes by reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR).

RESULTS

The sequencing of the RT-PCR amplicons confirmed the presence of both gonadotrophin receptors and immunohistochemistry localized them on the membrane of endometrial glands cells throughout the glandular epithelium. The gonadotrophin-receptor complex was able to increase the intracellular cAMP in a dose-response and time-course manner and to induce steroidogenic genes expression.

CONCLUSION

This study demonstrates that both gonadotrophin receptors are expressed along the glandular epithelium of endometria and they mediate the effects of gonadotrophins on intracellular functions.

[Natural cycle for frozen-thawed embryo transfer: Spontaneous ovulation or triggering by HCG]

OBJECTIVE

To compare frozen-thawed embryo transfer (FET) outcomes in natural cycles according to ovulation induction: spontaneous versus recombinant human chorionic gonadotrophin (r-hCG) triggering.

METHODS

This retrospective study included all patients monitored for natural cycle FET during one year. When serial monitoring were performed until spontaneous LH rise, patients were included in group A (n=38) whereas those receiving r-hCG for ovulation triggering formed group B (n=43). All embryos had been cryopreserved by a vitrification method following a previous IVF cycle. No luteal phase support had been given. We compared outcomes between the 2 groups.

RESULTS

After checking groups comparability, we didn't find significant difference for the implantation rate, clinical pregnancy rate and live birth (31% vs 45%, 32% vs 51% et 21% vs 32%, respectively for group A and B). The number of monitoring was significantly lower in group B (1,9±0,8 versus 2,5±1, P=0,006).

DISCUSSION

Although no consensus has been yet established, natural cycle seems indicated for normo-ovulating patients but the question of ovulation induction is still debated. In our study, triggering ovulation by r-hCG, respecting strict criteria, seems provide good results while reducing both protocol's constraints and cost.

hCG activates Epac-Erk1/2 signaling regulating Progesterone Receptor expression and function in human endometrial stromal cells

STUDY QUESTION

How does hCG signal in human endometrial stromal cells (ESCs) and what is its role in regulating ESC function?

SUMMARY ANSWER

hCG signaling in ESCs activates the extracellular signal-regulated protein kinases 1 and 2 (Erk1/2) pathway through exchange protein activated by cyclic AMP (cAMP) (Epac) and transiently increases progesterone receptor (PR) transcript and protein expression and its transcriptional function.

WHAT IS KNOWN ALREADY

hCG is one of the earliest embryo-derived secreted signals in the endometrium, which abundantly expresses LH/hCG receptors. hCG signals through cAMP/protein kinase A (PKA) in gonadal cells, but in endometrial epithelial cells, hCG induces Erk1/2 activation independent of the cAMP/PKA pathway. Few data exist concerning the signal transduction pathways triggered by hCG in ESCs and their role in regulation of ESC function.

STUDY DESIGN, SIZE, DURATION

This is an in vitro study comprising patients undergoing benign gynecological surgery (n = 46).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Endometrial samples were collected from normal cycling women during the mid-secretory phase for ESCs isolation. The study conducted in an academic research laboratory within a tertiary-care hospital. The activation of the Erk1/2 signal transduction pathway elicited by hCG was evaluated in ESC. Signaling pathway inhibitors were used to examine the roles of PKA, PI3K, PKC, adenylyl cyclase and Epac on the hCG-stimulated up-regulation of phospho-Erk1/2 (pErk1/2). Erk1/2 phosphorylation was determined by immunoblot. siRNA targeting Epac was used to investigate the molecular mechanisms. To assess the role of Erk1/2 signaling induced by hCG on ESC function, gene expression regulation was examined by immunofluorescence and real-time quantitative PCR. The role of PR on the regulation of transcript levels was studied using progesterone and the PR antagonist RU486. All experiments were conducted using at least three different cell culture preparations in triplicate.

MAIN RESULTS AND THE ROLE OF CHANCE

Addition of hCG to ESCs in vitro induced the phosphorylation of Erk1/2 through cAMP accumulation. Such induction could not be blocked by inhibitors for PKA, PKC and PI3K. Epac inhibition and knockdown with siRNA prevented pErk1/2 induction by hCG. ESCs stimulated with hCG for up to 72 h showed a significant increase in PR mRNA and immunofluorescent label at 48 h only; an effect that was abrogated with the mitogen-activated protein kinase kinase inhibitor UO126. In addition, the hCG-activated Erk1/2 pathway significantly decreased the mRNA levels for secreted frizzled-related protein 4 (SFRP4) at 24 h, whereas it increased those for homeobox A10 (HOXA10) at 48 h (P = 0.041 and P = 0.022 versus control, respectively). Prolactin mRNA levels were not significantly modified. HOXA10 mRNA up-regulation by hCG was not enhanced by co-stimulation with progesterone; however, it was completely abolished in the presence of RU486 (P = 0.036 hCG versus hCG + RU486).

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

This is an in vitro study utilizing stromal cell cultures from human endometrial tissues. Furthermore, results obtained should also be confirmed in vivo in the context of the whole human endometrial tissue and hormonal milieu. The in vitro experiments using hCG have been conducted without other hormones/factors that may also modulate the ESCs response to hCG.

WIDER IMPLICATIONS OF THE FINDINGS

We have determined that hCG induces the PR through the Erk1/2 pathway in ESCs which may render them more sensitive to progesterone, increasing our understanding about the effects of hCG at the embryo-maternal interface. The activation of such a pathway in the context of the hormonal milieu during the window of implantation might contribute to a successful dialog between the embryo and the uterus, leading to appropriate endometrial function. Defective hCG signaling in the endometrial stromal tissue may lead to an incomplete uterine response, compromising embryo implantation and early pregnancy.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the National Fund for Scientific and Technological Development, Government of Chile (FONDECYT) grants 11100443 and 1140614 (A.T.-P.). The authors have no conflicts of interest to declare.

A universal freeze all strategy: why it is not warranted

PURPOSE OF REVIEW

There's some preclinical evidence of an adverse effect of multifollicular growth on endometrial function in assisted reproductive technology cycles. Universal elective frozen embryo transfer (eFET) in an unstimulated cycle is being promoted as a panacea, regardless of patient, and cycle characteristics. We review the clinical evidence on the effectiveness and safety of eFETs.

RECENT FINDINGS

Randomized controlled trials (RCTs) comparing fresh and eFET yield contradictory results in terms of live birth rates. RCTs mainly involve women with an excessive response to ovarian stimulation. Studies including women with a normal or low ovarian response are either patient/physician preference or retrospective studies, prone to bias. Yet, they yield contradictory results as well. Overall, eFET seems to have limited potential to improve effectiveness of assisted reproductive technology, which could be limited to hyper-responders. Other suggested advantages of eFET include better obstetric and perinatal outcome. However, recent studies show that frozen embryo transfers can be associated with serious complications including hypertensive disorders during pregnancy, placenta accreta, or increased perinatal mortality.

SUMMARY

The evidence behind advantages of eFET is of low quality. As such, switching to a universal eFET strategy does not seem justified. New RCTs including women from different strata of ovarian response are needed.

Does ovarian reserve affect outcomes in single ideal blastocyst transfers in women less than 40 years of age?

PURPOSE

There is much debate whether diminished ovarian reserve is purely a quantitative issue, or if quality as determined by pregnancy potential of the ensuing oocytes is also affected. The purpose of this study was to determine whether diminished ovarian reserve, as established by one of three ways described below, affects pregnancy outcomes of women under 40 years old undergoing a single ideal blastocyst transfer.

MATERIALS AND METHODS

This was a retrospective cohort study, including 507 women undergoing an ideal quality single embryo transfer between August 2010 and March 2014. Logistic regression was used to control for age, duration of infertility, parity, body mass index, and smoking status. For analysis, women were stratified for: antral follicle counts (≤ 5 vs. > 5), basal serum FSH levels (< 13 vs. ≥ 13 IU/L), and quartile of total FSH dose required for stimulation.

RESULTS

In stratifying women by antral follicle count (AFC) ≤ 5 vs. > 5, the pregnancy rate (40 vs. 53%, p = 0.04), clinical pregnancy rate (29 vs. 46%, p = 0.02), and live birth rate (13 vs. 43%, p = 0.001) were superior with AFC > 5. Using FSH levels (< 13 vs. ≥ 13 IU/L), the pregnancy rate (50 vs. 31%, p = 0.27), clinical pregnancy rate (40 vs. 13%, p = 0.45), and live birth rate (38 vs. 13%, p = 0.48) were similar. Examining quartiles of FSH stimulation, the pregnancy rates were similar (from lowest to highest: 45, 52, 54, 41%, p = 0.13); however, clinical pregnancy rate (36, 43, 47, 25%, p = 0.003) and live birth rate (32, 38, 44, 20%, p = 0.005) were superior in lower quartiles vs. the highest quartile.

CONCLUSION

Ovarian reserve may affect embryo pregnancy potential and outcomes when measured by AFC and exogenous stimulation but not by basal FSH levels.

The Role of HCG in Implantation: A Mini-Review of Molecular and Clinical Evidence

Embryo implantation is a complex process involving continuous molecular cross-talk between the embryo and the decidua. One of the key molecules during this process is human chorionic gonadotropin (HCG). HCG effectively modulates several metabolic pathways within the decidua contributing to endometrial receptivity. Herein, a brief overview of the molecular mechanisms regulated by HCG is presented. Furthermore, we summarize the existing evidence regarding the clinical impact on reproductive outcomes after endometrial priming with HCG prior to embryo transfer. Although promising, further evidence is needed to clarify the protocol that would lead to beneficial outcomes.

Timing therapeutic donor inseminations in natural cycles: human chorionic gonadotrophin administration versus urinary LH monitoring

This cohort study assessed whether timing therapeutic donor sperm inseminations (TDI) in natural cycles (NC) using ultrasound monitoring and ovulation trigger with human chorionic gonadotrophin (US/HCG) improves cumulative live birth rates (LBR) compared with detection of LH surge with urinary kits (u-LH). It included 232 normo-ovulatory women aged ≤40 years, undergoing 538 TDI in NC between 2011 and 2014. In the u-LH group (113 women, 267 cycles), TDI was performed the day following a positive test. In the US/HCG group (119 women, 271 cycles), ovulation was triggered with HCG when a follicle ≥17 mm was noted, and TDI performed 36 h later. The first three cycles were analysed per patient. Groups were comparable for baseline characteristics. Cumulative LBR were comparable between u-LH and US/HCG groups (31.47% versus 23.11%, respectively) (log-rank test). A generalized estimating equation analysis was performed to compare outcomes per cycle. The LBR per started cycle was comparable between the u-LH and US/HCG groups (12.4% versus 9.2%, respectively). Cancellation rate was significantly higher with u-LH (19.1% versus 11.4%, P = 0.011), but did not impact overall outcomes. In conclusion, urinary LH monitoring is as effective as ultrasound monitoring and ovulation trigger with HCG in TDI performed in NC.

The high responder: a review of pathophysiology and outcomes during IVF treatment

This review attempts to summarize the known literature on high responders to ovarian stimulation during assisted reproductive techniques (ART). Response to gonadotrophins is subject to significant interindividual and intercycle variation, thus carrying a risk of high response or poor response to ovarian stimulation regimens. The main risk for high responders is the development of ovarian hyperstimulation syndrome (OHSS) which is associated with significant morbidity. Hence, the definition of high responders in the literature has primarily focussed on risk factors for OHSS. Strategies to reduce OHSS including tailoring of the ovarian stimulation regimens and adjusting gonadotrophin doses according to patient characteristics and findings during the cycle of stimulation. In addition, modifying the type of ovulation trigger used and adjuvant therapies, such as metformin, intravenous colloids and vascular endothelial growth factor blockers, have also been studied as options to reduce OHSS. Apart from the risk of OHSS, high response also appears to have an adverse impact on the oocyte and endometrium, though there is a paucity of data regarding the extent and mechanisms behind this impact.

Human chorionic gonadotropin potentially affects pregnancy outcome in women with recurrent implantation failure by regulating the homing preference of regulatory T cells

PROBLEM

Human chorionic gonadotropin (hCG) and regulatory T cells (Tregs) have been suggested to play important roles during the initial stage of pregnancy. However, the clinical relevance and mechanism of the effects of hCG on Treg functions in women with recurrent implantation failure (RIF) remain to be elucidated.

METHOD OF STUDY

Thirty-four RIF and twenty-three control women were included in the study. Endometrial and peripheral Tregs were analyzed by immunohistochemistry and flow cytometry, respectively. Tregs were generated from naïve CD4⁺ T cells by stimulation with anti-CD3/CD28 in the presence or absence of hCG, and the subsets were analyzed by flow cytometry, Western blotting, and qPCR.

RESULTS

The percentages of endometrial FOXP3⁺ Tregs and peripheral CCR4⁺ FOXP3⁺ Tregs were significantly lower in the women with RIF than in the healthy controls. In addition, the percentages of CCR4⁺ FOXP3⁺ Tregs and TGF-β-expressing FOXP3⁺ Tregs were increased following the stimulation of naïve CD4⁺ T cells with anti-CD3/CD28, and these increases were concomitant with AKT and ERK dephosphorylation.

CONCLUSIONS

The results of this study provide novel evidence supporting a role of hCG in regulating the differentiation of peripheral FOXP3⁺ Tregs. The alterations of circulating Tregs may positively affect the pregnancy outcomes of patients with a history of RIF.

Micro-dose hCG as luteal phase support without exogenous progesterone administration: mathematical modelling of the hCG concentration in circulation and initial clinical experience

For the last two decades, exogenous progesterone administration has been used as luteal phase support (LPS) in connection with controlled ovarian stimulation combined with use of the human chorionic gonadotropin (hCG) trigger for the final maturation of follicles. The introduction of the GnRHa trigger to induce ovulation showed that exogenous progesterone administration without hCG supplementation was insufficient to obtain satisfactory pregnancy rates. This has prompted development of alternative strategies for LPS. Augmenting the local endogenous production of progesterone by the multiple corpora lutea has been one focus with emphasis on one hand to avoid development of ovarian hyper-stimulation syndrome and, on the other hand, to provide adequate levels of progesterone to sustain implantation. The present study evaluates the use of micro-dose hCG for LPS support and examines the potential advances and disadvantages. Based on the pharmacokinetic characteristics of hCG, the mathematical modelling of the concentration profiles of hCG during the luteal phase has been evaluated in connection with several different approaches for hCG administration as LPS. It is suggested that the currently employed LPS provided in connection with the GnRHa trigger (i.e. 1.500 IU) is too strong, and that daily micro-dose hCG administration is likely to provide an optimised LPS with the current available drugs. Initial clinical results with the micro-dose hCG approach are presented.

The effect of intrauterine HCG injection on IVF outcome: a systematic review and meta-analysis

In this systematic review and meta-analysis, the effect of intrauterine HCG infusion before embryo transfer on IVF outcomes (live birth rate, clinical pregnancy rate and spontaneous aboretion rate) was investigated. Searches were conducted on MEDLINE, EMBASE and The Cochrane Library. Randomized studies in women undergoing IVF and intracytoplasmic sperm injection comparing intrauterine HCG administration at embryo transfer compared with no intrauterine HCG were eligible for inclusion. Eight randomized controlled trials were eligible for inclusion in the meta-analysis. A total of 3087 women undergoing IVF and intracytoplasmic sperm injection cycles were enrolled (intrauterine HCG group: n = 1614; control group: n = 1473). No significant difference was found in the live birth rate (RR 1.13; 95% CI 0.84 to 1.53) and spontaneous abortion rate (RR 1.00, 95% CI 0.74 to 1.34) between women who received intrauterine HCG and those who did not receive HCG. Although this review was extensive and included randomized controlled trials, no significant heterogeneity was found, and the overall included numbers are relatively small. In conclusion the current evidence does not support the use of intrauterine HCG administration before embryo transfer. Well-designed multicentre trials are needed to provide robust evidence.

Modulating the endometrial epithelial proteome and secretome in preparation for pregnancy: The role of ovarian steroid and pregnancy hormones

Dialogue between an appropriately developed embryo and hormonally-primed endometrium is essential to achieve implantation and establish pregnancy. Importantly, the point-of-first-contact between the embryo and the maternal endometrium occurs at the endometrial luminal epithelium (LE). Implantation events occur within the uterine cavity microenvironment regulated by local factors. Defects in embryo-endometrial communication likely underlie unexplained infertility; enhanced knowledge of this communication, specifically at initial maternal-fetal contact may reveal targets to improve fertility. Using a human endometrial luminal-epithelial (LE) cell line (ECC1), this targeted proteomic study reveals unique protein changes in both cellular (98% unique identifications) and secreted (96% unique identifications) proteins in the transition to the progesterone-dominated secretory (receptive) phase and subsequently to pregnancy, mediated by embryo-derived human chorionic gonadotropin (hCG). This analysis identified 157 progesterone-regulated cellular proteins, with further 193 significantly altered in response to hCG. Cellular changes were associated with metabolism, basement membrane and cell connectivity, proliferation and differentiation. Secretome analysis identified 1059 proteins; 123 significantly altered by progesterone, and 43 proteins altered by hCG, including proteins associated with cellular adhesion, extracellular-matrix organization, developmental growth, growth factor regulation, and cell signaling. Collectively, our findings reveal dynamic intracellular and secreted protein changes in the endometrium that may modulate successful establishment of pregnancy.

BIOLOGICAL SIGNIFICANCE

This study provides unique insights into the developmental biology of embryo implantation using targeted proteomics by identifying endometrial epithelial cellular and secreted protein changes in response to ovarian steroid hormones and pregnancy hormones that are essential for receptivity and implantation.

Human Endometrial Exosomes Contain Hormone-Specific Cargo Modulating Trophoblast Adhesive Capacity: Insights into Endometrial-Embryo Interactions

Embryo implantation into receptive endometrium requires synergistic endometrial-blastocyst interactions within the uterine cavity and is essential for establishing pregnancy. We demonstrate that exosomes (40-150 nm nanovesicles) released from endometrial epithelial cells are an important component of these interactions. We defined the proteome of purified endometrial epithelial-derived exosomes (Exos) influenced by menstrual cycle hormones estrogen (E; proliferative phase) and estrogen plus progesterone (EP; receptive phase) and examined their potential to modify trophoblast function. E-/EP-Exos were uniquely enriched with 254 and 126 proteins, respectively, with 35% newly identified proteins not previously reported in exosome databases. Importantly, EP-Exos protein cargo was related to fundamental changes in implantation: adhesion, migration, invasion, and extracellular matrix remodeling. These findings from hormonally treated ECC1 endometrial cancer cells were validated in human primary uterine epithelial cell-derived exosomes. Functionally, exosomes were internalized by human trophoblast cells and enhanced their adhesive capacity, a response mediated partially through active focal adhesion kinase (FAK) signaling. Thus, exosomes contribute to the endometrial-embryo interactions within the human uterine microenvironment essential for successful implantation.

The Microenvironment of Human Implantation: Determinant of Reproductive Success

Successful implantation requires synchronous development of embryo and endometrium. Endometrial receptivity results from progesterone-induced differentiation of endometrial cells, generally achieved during the mid-secretory phase of the cycle. Failure to properly develop receptivity results in failed or inadequate implantation and hence no ongoing pregnancy. The blastocyst undergoes final development, apposition, attachment and initiates invasion of the endometrial epithelium within the uterine cavity. Thus, the microenvironment provided by uterine fluid, particularly glandular secretions, is essential for implantation. Analysis of endometrial fluid has identified cytokines, chemokines, proteases, antiproteases and other factors that modulate blastocyst functions relevant to implantation. Exosomes/microvesicular bodies released from the endometrium (and likely also the embryo) are present in uterine fluid. These can transfer miRNA, proteins and lipids between cells, thus providing endometrial-embryo communication in the peri-implantation period. Understanding the uterine microenvironment, and its effects on endometrial-embryo interactions, will provide opportunities to modify current infertility treatments to improve success rates.

Administering human chorionic gonadotropin injections for triggering follicle maturation could impact fertility during the subsequent menstrual cycle

OBJECTIVE

To determine whether the use of a human chorionic gonadotropin (hCG) injection as a follicle-maturation trigger affects a patient's reproductive ability during their subsequent menstrual cycle.

METHODS

Patients that were infertile undergoing natural-cycle in vitro fertilization at Kato Ladies Clinic, Japan, between March and June 2012 were enrolled in a prospective cohort study. Patients who had received fertility treatments other than hCG injections were excluded from the study. The remaining patients were divided into two cohorts; patients who had received injection-administered hCG (study group) and patients who had not received any fertility treatment (control group) during their preceding menstrual cycle. The rates of oocyte retrieval, fertilization, clinical pregnancy, and live deliveries were analyzed using a Fisher exact test.

RESULTS

The rate of successful oocyte-retrieval (P<0.001) and the delivery-rate (P=0.002) were significantly lower in the study group in comparison with the control group. Additionally, the incidence of empty follicles (P<0.001) and degenerated oocytes (P=0.002) was significantly higher in the exposure group.

CONCLUSION

Triggering follicle maturation with hCG during in vitro fertilization could impact patient fertility during their next cycle. Treatment with hCG injection has the potential to influence not only the cycle during which it is administered, but also the subsequent menstrual cycle.

Controlled Ovarian Stimulation with recombinant-FSH plus recombinant-LH vs. human Menopausal Gonadotropin based on the number of retrieved oocytes: results from a routine clinical practice in a real-life population

BACKGROUND

The association of recombinant FSH (rFSH) plus recombinant LH (rLH) is currently used for Controlled Ovarian Stimulation (COS) in human IVF, but its efficacy has, to date, not yet been compared to that of human Menopausal Gonadotropin (hMG), the FSH + LH activity-containing urinary drug.

METHODS

Eight hundred forty-eight (848) IVF patients classified as expected "poor" or "normal" responders according to antral follicle count (AFC) and basal (day 3) FSH were treated with rFSH + rLH (2:1 ratio, n = 398, Group A) or hMG (n = 450, Group B). Data were collected under real-life practice circumstances and the pregnancy rate with fresh embryos was calculated by stratifying patients according to the number of retrieved oocytes (1-2, 3-4, 5-6, 7-8, >8).

RESULTS

Overall, the pregnancy rate in both groups progressively improved according to the number of oocytes retrieved. When comparing patients within the same subgroup of oocyte yield, Group A and B showed a comparable outcome up to the reported highest yield (>8). When more than 8 oocytes were available, Group A had a significantly better pregnancy rate outcome. Patients' characteristics did not significantly differ between the two groups and the better outcome in the best responding patients in Group A was confirmed by a multivariable logistic regression analysis, that showed that both the use of rFSH + rLH and the total number of retrieved oocytes increased the probability of pregnancy with odd ratio (OR) of 1.628 and 1.083, respectively.

CONCLUSIONS

When comparing patients with the same number of retrieved oocytes under real-life circumstances, the association of rFSH + rLH results in a significantly higher pregnancy rate than hMG when more than 8 oocytes are retrieved. The reason(s) for this are unknown, but a more favorable effect on oocyte quality and/or endometrial receptivity could be involved.

Fresh versus frozen embryo transfer: backing clinical decisions with scientific and clinical evidence

BACKGROUND

Improvements in vitrification now make frozen embryo transfers (FETs) a viable alternative to fresh embryo transfer, with reports from observational studies and randomized controlled trials suggesting that: (i) the endometrium in stimulated cycles is not optimally prepared for implantation; (ii) pregnancy rates are increased following FET and (iii) perinatal outcomes are less affected after FET.

METHODS

This review integrates and discusses the available clinical and scientific evidence supporting embryo transfer in a natural cycle.

RESULTS

Laboratory-based studies demonstrate morphological and molecular changes to the endometrium and reduced responsiveness of the endometrium to hCG, resulting from controlled ovarian stimulation. The literature demonstrates reduced endometrial receptivity in controlled ovarian stimulation cycles and supports the clinical observations that FET reduces the risk of ovarian hyperstimulation syndrome and improves outcomes for both the mother and baby.

CONCLUSIONS

This review provides the basis for an evidence-based approach towards changes in routine IVF, which may ultimately result in higher delivery rates of healthier term babies.