Analysis of serum and endometrial progesterone in determining endometrial receptivity

Clinical outcomes of frozen-thawed embryo transfer in natural cycles with luteinized unruptured follicles

OBJECTIVE

To assess the effect of luteinized unruptured follicles (LUF) on frozen-thawed embryo transfer cycles performed in natural cycles (FET-NC).

METHODS

Retrospective cohort study, held in a university hospital with 3415 cycles for frozen-thawed embryo transfer, performed between June 2019 and September 2022. Using propensity score matching, 242 patients with a diagnosis of LUF (LUF group) were matched with 484 ovulated patients (ovulation group). Stratified by the type of embryo transferred, the LUF group included 168 blastocyst transfer patients (blastocyst group) and 74 cleavage-stage embryo transfer patients (cleavage-embryo group). The ovulation group included 324 patients with blastocyst transfer (blastocyst group) and 160 patients with transferred cleavage-stage embryos. Clinical pregnancy rate was retrospectively analyzed between the LUF and ovulation groups, as well as between each subgroup.

RESULTS

After using propensity score matching, the general characteristics of the LUF and ovulation groups were similar. The implantation and clinical pregnancy rates in the LUF group were not significantly different from those in the ovulation group (44.98 % vs. 45.29 %, p = 0.93; 53.72 % vs. 52.48 %, p = 0.75). The implantation and pregnancy rates of transferred cleavage-stage embryos in the LUF group were also not significantly different from those in the ovulation group (32.39 % vs. 36.40 %, p = 0.42; 47.30 % vs. 47.50 %, p = 0.98). The implantation and pregnancy rates of transferred blastocysts in the LUF group were also not significantly different from those in the ovulation group (53.11 % vs. 52.03 %, p = 0.82; 56.55 % vs. 54.94 %, p = 0.73). There was also no significant difference in the miscarriage rate between the groups.

CONCLUSION

In the natural cycle, LUF does not affect the clinical pregnancy outcomes of FET. If adequate luteal support is given, the clinical pregnancy outcomes were similar between the LUF group and ovulation group.

The Effect of Granulocyte Colony-Stimulating Factor on Endometrial Receptivity of Implantation Failure Mouse

The purpose of this study was to investigate the effect of G-CSF on the endometrial receptivity of implantation failure mice. Sixty female mice were treated mifepristone to establish an implant failure model. The treatment groups received different doses of G-CSF. Endometrial tissue and serum were collected on day 5 after mating. The abundance of pinopodes on the endometrium was observed by scanning electron microscopy. The expressions of LPAR3, COX2, and HOXA10 were detected by RT-qPCR and Western blotting. Serum levels of E2, P, VEGF, LIF, TNF-α and IL-10 were measured by ELISA. The expressions of VEGF, CD34, CD57, TNF-α, and IL-10 were assessed by immunohistochemistry. Immunofluorescence analysis was performed to determine the number of CD57, Treg, and Th17 cells. G-CSF increased implantation and pregnancy rates of mifepristone-induced implantation failure mice, with the most significant effect seen at the intermediate dose. G-CSF increased the serum levels of E2 and P, the abundance of endometrial pinopodes, and the level of LIF in the endometrium. It also promoted the expression of VEGF, HOXA10, LPAR3, and COX2. Moreover, G-CSF reduced the level of CD57 cells and the ratio of Th17/Treg cells in endometrium. G-CSF reduced the inflammatory factor TNF-α, but IL-10 did not change significantly. G-CSF can enhance embryo implantation rate and pregnancy rate and improve endometrial receptivity by attenuating degeneration of pinopodes, upregulating estrogen and progesterone, facilitating angiogenesis, maintaining immune cell homeostasis, and reducing the production of inflammatory cytokines in implantation failure mouse.

The combination of dydrogesterone and micronized vaginal progesterone can render serum progesterone level measurements on the day of embryo transfer and rescue attempts unnecessary in an HRT FET cycle

PURPOSE

To evaluate the role of serum progesterone (P4) on the day of embryo transfer (ET) when dydrogesterone (DYD) and micronized vaginal progesterone (MVP) are combined as luteal phase support (LPS) in a hormone replacement therapy (HRT) frozen ET (FET) cycles.

METHODS

Retrospective study, including single euploid HRT FET cycles with DYD and MVP as LPS and P4 measurement on ET day. Initially, patients with P4 levels < 10 ng/ml increased MVP to 400 mg/day; this "rescue" was abandoned later.

RESULTS

560 cycles of 507 couples were included. In 275 women, serum P4 level was < 10 ng/ml on the ET day. Among those with low P4 levels, MVP dose remained unchanged in 65 women (11.6%) and was increased in 210 women (37.5%). Women with P4 levels ≥ 10 ng/ml continued LPS without modification. Overall pregnancy rates in these groups were 61.5% (40/65), 54.8% (115/210), and 48.4% (138/285), respectively (p = n.s.). Association of serum P4 levels with ongoing pregnancy rates was analyzed in women without any additional MVP regardless of serum P4 levels (n = 350); multivariable analysis (adjusted for age, BMI, embryo quality (EQ)) did not show a significant association of serum P4 levels with OPR (OR 0.96, 95% CI 0.90-1.02; p = 0.185). Using inverse probability treatment weights, regression analysis in the weighted sample showed no significant association between P4 treatment groups and OP. Compared to fair EQ, the transfer of good EQ increased (OR 1.61, 95% CI 1.22-2.15; p = 0.001) and the transfer of a poor EQ decreased the odds of OP (OR 0.73, 95% CI 0.55-0.97; p = 0.029).

CONCLUSION

In HRT FET cycle, using LPS with 300 mg/day MVP and 30 mg/day DYD, it appears that serum P4 measurement and increase of MVP in patients with P4 < 10 ng/ml are not necessary.

Luteal phase support in assisted reproductive technology

Infertility affects one in six couples, with in vitro fertilization (IVF) offering many the chance of conception. Compared to the solitary oocyte produced during the natural menstrual cycle, the supraphysiological ovarian stimulation needed to produce multiple oocytes during IVF results in a dysfunctional luteal phase that can be insufficient to support implantation and maintain pregnancy. Consequently, hormonal supplementation with luteal phase support, principally exogenous progesterone, is used to optimize pregnancy rates; however, luteal phase support remains largely 'black-box' with insufficient clarity regarding the optimal timing, dosing, route and duration of treatment. Herein, we review the evidence on luteal phase support and highlight remaining uncertainties and future research directions. Specifically, we outline the physiological luteal phase, which is regulated by progesterone from the corpus luteum, and evaluate how it is altered by the supraphysiological ovarian stimulation used during IVF. Additionally, we describe the effects of the hormonal triggers used to mature oocytes on the degree of luteal phase support required. We explain the histological transformation of the endometrium during the luteal phase and evaluate markers of endometrial receptivity that attempt to identify the 'window of implantation'. We also cover progesterone receptor signalling, circulating progesterone levels associated with implantation, and the pharmacokinetics of available progesterone formulations to inform the design of luteal phase support regimens.

Endometrial receptivity in women with endometriosis

As endometriosis is recognized as a contributing factor to infertility, prompting couples to embark on Assisted Reproductive Technology (ART) treatments, it becomes crucial to comprehend the extent and way this condition can affect success rates. Natural conception data reveal lower success rates for women with endometriosis, yet the same cannot be extrapolated to the outcomes of in vitro fertilization (IVF). In recent years, advancements in the ART process, particularly the distinct stages of the IVF pathway and investigations into embryo quality have shown a comparable rate of embryonic quality and chromosomal normalcy (euploidy) between embryos obtained from individuals with or without endometriosis. Thus, the primary question that lingers relates to the functionality of the endometrium. This review addresses whether endometriosis can influence endometrial receptivity and implantation rates.

Oral dydrogesterone versus micronized vaginal progesterone for luteal phase support: a double-blind crossover study investigating pharmacokinetics and impact on the endometrium

STUDY QUESTION

How do plasma progesterone (P) and dydrogesterone (D) concentrations together with endometrial histology, transcriptomic signatures, and immune cell composition differ when oral dydrogesterone (O-DYD) or micronized vaginal progesterone (MVP) is used for luteal phase support (LPS)?

SUMMARY ANSWER

Although after O-DYD intake, even at steady-state, plasma D and 20αdihydrodydrogesterone (DHD) concentrations spiked in comparison to P concentrations, a similar endometrial signature was observed by histological and transcriptomic analysis of the endometrium.

WHAT IS KNOWN ALREADY

O-DYD for LPS has been proven to be noninferior compared to MVP in two phase III randomized controlled trials. Additionally, a combined individual participant data and aggregate data meta-analysis indicated that a higher pregnancy rate and live birth rate may be obtained in women receiving O-DYD versus MVP for LPS in fresh IVF/ICSI cycles. Little data are available on the pharmacokinetic (PK) profiles of O-DYD versus MVP and their potential molecular differences at the level of the reproductive organs, particularly at the endometrial level.

STUDY DESIGN, SIZE, DURATION

Thirty oocyte donors were planned to undergo two ovarian stimulation (OS) cycles with dual triggering (1.000 IU hCG + 0.2 mg triptorelin), each followed by 1 week of LPS: O-DYD or MVP, in a randomized, cross-over, double-blind, double-dummy fashion. On both the first and eighth days of LPS, serial blood samples upon first dosing were harvested for plasma D, DHD, and P concentration analyses. On Day 8 of LPS, an endometrial biopsy was collected for histologic examination, transcriptomics, and immune cell analysis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All oocyte donors were <35 years old, had regular menstrual cycles, no intrauterine contraceptive device, anti-Müllerian hormone within normal range and a BMI ≤29 kg/m2. OS was performed on a GnRH antagonist protocol followed by dual triggering (1.000 IU hCG + 0.2 mg triptorelin) as soon as ≥3 follicles of 20 mm were present. Following oocyte retrieval, subjects initiated LPS consisting of MVP 200 mg or O-DYD 10 mg, both three times daily. D, DHD, and P plasma levels were measured using liquid chromatography-tandem mass spectrometry. Histological assessment was carried out using the Noyes criteria. Endometrial RNA-sequencing was performed for individual biopsies and differential gene expression was analyzed. Endometrial single-cell suspensions were created followed by flow cytometry for immune cell typing.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 21 women completed the entire study protocol. Subjects and stimulation characteristics were found to be similar between groups. Following the first dose of O-DYD, the average observed maximal plasma concentrations (Cmax) for D and DHD were 2.9 and 77 ng/ml, respectively. The Cmax for D and DHD was reached after 1.5 and 1.6 h (=Tmax), respectively. On the eighth day of LPS, the first administration of that day gave rise to a Cmax of 3.6 and 88 ng/ml for D and DHD, respectively. For both, the observed Tmax was 1.5 h. Following the first dose of MVP, the Cmax for P was 16 ng/ml with a Tmax of 4.2 h. On the eighth day of LPS, the first administration of that day showed a Cmax for P of 21 ng/ml with a Tmax of 7.3 h. All 42 biopsies showed endometrium in the secretory phase. The mean cycle day was 23.9 (±1.2) in the O-DYD group versus 24.0 (±1.3) in the MVP group. RNA-sequencing did not reveal significantly differentially expressed genes between samples of both study groups. The average Euclidean distance between samples following O-DYD was significantly lower than following MVP (respectively 12.1 versus 18.8, Mann-Whitney P = 6.98e-14). Immune cell profiling showed a decrease of CD3 T-cell, γδ T-cell, and B-cell frequencies after MVP treatment compared to O-DYD, while the frequency of natural killer (NK) cells was significantly increased.

LIMITATIONS, REASONS FOR CAUTION

The main reason for caution is the small sample size, given the basic research nature of the project. The plasma concentrations are best estimates as this was not a formal PK study. Whole tissue bulk RNA-sequencing has been performed not correcting for bias caused by different tissue compositions across biopsies.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study comparing O-DYD/MVP, head-to-head, in a randomized design on a molecular level in IVF/ICSI. Plasma serum concentrations suggest that administration frequency is important, in addition to dose, specifically for O-DYD showing a rapid clearance. The molecular endometrial data are overall comparable and thus support the previously reported noninferior reproductive outcomes for O-DYD as compared to MVP. Further research is needed to explore the smaller intersample distance following O-DYD and the subtle changes detected in endometrial immune cells.

STUDY FUNDING/COMPETING INTEREST(S)

Not related to this work, C.Bl. has received honoraria for lectures, presentations, manuscript writing, educational events, or scientific advice from Abbott, Ferring, Organon, Cooper Surgical, Gedeon-Richter, IBSA, and Merck. H.T. has received honoraria for lectures, presentations, manuscript writing, educational events, or scientific advice from Abbott, Ferring, Cooper Surgical, Gedeon-Richter, Cook, and Goodlife. S.M. has received honoraria for lectures, presentations, educational events, or scientific advice from Abbott, Cooper Surgical, Gedeon-Richter, IBSA, and Merck and Oxolife. G.G. has received honoraria for lectures, presentations, educational events, or scientific advice from Merck, MSD, Organon, Ferring, Theramex, Gedeon-Richter, Abbott, Biosilu, ReprodWissen, Obseva, PregLem, Guerbet, Cooper, Igyxos, and OxoLife. S.V.-S. is listed as inventor on two patents (WO2019115755A1 and WO2022073973A1), which are not related to this work.

TRIAL REGISTRATION NUMBER

EUDRACT 2018-000105-23.

Mechanisms of Bushen Tiaoxue Granules against controlled ovarian hyperstimulation-induced abnormal morphology of endometrium based on network pharmacology

Bushen Tiaoxue Granules (BTG) is an empirical Chinese herbal formula that has been used for the treatment of subfertility. The protective effect of BTG on controlled ovarian hyperstimulation (COH)-induced impaired endometrial receptivity has been reported in our previous study. This study aims to explore the mechanisms of BTG on ameliorating abnormal morphology of endometrium based on network pharmacology. Active compounds of BTG were identified via the traditional Chinese medicine systems pharmacology and UPLC-MS technology. The SwissTargetPrediction platform and HERB database were used to screen out the putative targets of BTG. Potential targets of endometrial dysfunction caused by COH were obtained from three GEO databases. Through the STRING database, the protein-protein interaction was carried out according to the cross-common targets of diseases and drugs. GO terms and KEGG pathways enrichment analyses were conducted via the Metascape database. AutoDock Vina was used for docking validation of the affinity between active compounds and potential targets. Finally, in vivo experiments were used to verify the potential mechanisms derived from network pharmacology study. A total of 141 effective ingredients were obtained from TCMSP and nine of which were verified in UPLC-MS. Six genes were selected through the intersection of 534 disease related genes and 165 drug potential targets. Enrichment analyses showed that BTG might reverse endometrial dysfunction by regulating adherens junction and arachidonic acid metabolism. Hematoxylin-eosin staining revealed that BTG ameliorated the loose and edematous status of endometrial epithelium caused by COH. The protein expression of FOXO1A, β-Catenin and COX-2 was decreased in the COH group, and was up-regulated by BTG. BTG significantly alleviates the edema of endometrial epithelium caused by COH. The mechanisms may be related to adheren junctions and activation of arachidonic acid metabolism. The potential active compounds quercetin, taxifolin, kaempferol, eriodictyol, and isorhamnetin identified from the BTG exhibit marginal cytotoxicity. Both high and low concentrations of kaempferol, eriodictyol, and taxifolin are capable of effectively ameliorating impaired hESC cellular activity.

C11-hydroxy and C11-oxo C19 and C21 Steroids: Pre-Receptor Regulation and Interaction with Androgen and Progesterone Steroid Receptors

C11-oxy C19 and C11-oxy C21 steroids have been identified as novel steroids but their function remains unclear. This study aimed to investigate the pre-receptor regulation of C11-oxy steroids by 11β-hydroxysteroid dehydrogenase (11βHSD) interconversion and potential agonist and antagonist activity associated with the androgen (AR) and progesterone receptors (PRA and PRB). Steroid conversions were investigated in transiently transfected HEK293 cells expressing 11βHSD1 and 11βHSD2, while CV1 cells were utilised for agonist and antagonist assays. The conversion of C11-hydroxy steroids to C11-oxo steroids by 11βHSD2 occurred more readily than the reverse reaction catalysed by 11βHSD1, while the interconversion of C11-oxy C19 steroids was more efficient than C11-oxy C21 steroids. Furthermore, 11-ketodihydrotestosterone (11KDHT), 11-ketotestosterone (11KT) and 11β-hydroxydihydrotestosterone (11OHDHT) were AR agonists, while only progestogens, 11β-hydroxyprogesterone (11βOHP4), 11β-hydroxydihydroprogesterone (11βOHDHP4), 11α-hydroxyprogesterone (11αOHP4), 11α-hydroxydihydroprogesterone (11αOHDHP4), 11-ketoprogesterone (11KP4), 5α-pregnan-17α-diol-3,11,20-trione (11KPdione) and 21-deoxycortisone (21dE) exhibited antagonist activity. C11-hydroxy C21 steroids, 11βOHP4, 11βOHDHP4 and 11αOHP4 exhibited PRA and PRB agonistic activity, while only C11-oxo steroids, 11KP4 and 11-ketoandrostanediol (11K3αdiol) demonstrated PRB agonism. While no steroids antagonised the PRA, 11OHA4, 11β-hydroxytestosterone (11OHT), 11KT and 11KDHT exhibited PRB antagonism. The regulatory role of 11βHSD isozymes impacting receptor activation is clear-C11-oxo androgens exhibit AR agonist activity; only C11-hydroxy progestogens exhibit PRA and PRB agonist activity. Regulation by the downstream metabolites of active C11-oxy steroids at the receptor level is apparent-C11-hydroxy and C11-oxo metabolites antagonize the AR and PRB, progestogens the former, androgens the latter. The findings highlight the intricate interplay between receptors and active as well as "inactive" C11-oxy steroids, suggesting novel regulatory tiers.

Rectal progesterone administration secures a high ongoing pregnancy rate in a personalized Hormone Replacement Therapy Frozen Embryo Transfer (HRT-FET) protocol: a prospective interventional study

STUDY QUESTION

Can supplementation with rectal administration of progesterone secure high ongoing pregnancy rates (OPRs) in patients with low serum progesterone (P4) on the day of blastocyst transfer (ET)?

SUMMARY ANSWER

Rectally administered progesterone commencing on the ET day secures high OPRs in patients with serum P4 levels below 35 nmol/l (11 ng/ml).

WHAT IS KNOWN ALREADY

Low serum P4 levels at peri-implantation in Hormone Replacement Therapy Frozen Embryo Transfer (HRT-FET) cycles impact reproductive outcomes negatively. However, studies have shown that patients with low P4 after a standard vaginal progesterone treatment can obtain live birth rates (LBRs) comparable to patients with optimal P4 levels if they receive additionalsubcutaneous progesterone, starting around the day of blastocyst transfer. In contrast, increasing vaginal progesterone supplementation in low serum P4 patients does not increase LBR. Another route of administration rarely used in ART is the rectal route, despite the fact that progesterone is well absorbed and serum P4 levels reach a maximum level after ∼2 h.

STUDY DESIGN, SIZE, DURATION

This prospective interventional study included a cohort of 488 HRT-FET cycles, in which a total of 374 patients had serum P4 levels ≥35 nmol/l (11 ng/ml) at ET, and 114 patients had serum P4 levels <35 nmol/l (11 ng/ml). The study was conducted from January 2020 to November 2022.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients underwent HRT-FET in a public Fertility Clinic, and endometrial preparation included oral oestradiol (6 mg/24 h), followed by vaginal micronized progesterone, 400 mg/12 h. Blastocyst transfer and P4 measurements were performed on the sixth day of progesterone administration. In patients with serum P4 <35 nmol/l (11 ng/ml), 'rescue' was performed by rectal administration of progesterone (400 mg/12 h) starting that same day. In pregnant patients, rectal administration continued until Week 8 of gestation, and oestradiol and vaginal progesterone treatment continued until Week 10 of gestation.

MAIN RESULTS AND THE ROLE OF CHANCE

Among 488 HRT-FET single blastocyst transfers, the mean age of the patients at oocyte retrieval (OR) was 30.9 ± 4.6 years and the mean BMI at ET 25.1 ± 3.5 kg/m2. The mean serum P4 level after vaginal progesterone administration on the day of ET was 48.9 ± 21.0 nmol/l (15.4 ± 6.6 ng/ml), and a total of 23% (114/488) of the patients had a serum P4 level lower than 35 nmol/l (11 ng/ml). The overall, positive hCG rate, clinical pregnancy rate, OPR week 12, and total pregnancy loss rate were 66% (320/488), 54% (265/488), 45% (221/488), and 31% (99/320), respectively. There was no significant difference in either OPR week 12 or total pregnancy loss rate between patients with P4 ≥35 nmol/l (11 ng/ml) and patients with P4 <35 nmol/l, who received rescue in terms of rectally administered progesterone, 45% versus 46%, P = 0.77 and 30% versus 34%, P = 0.53, respectively. OPR did not differ whether patients had initially low P4 and rectal rescue or were above the P4 cut-off. Logistic regression analysis showed that only age at OR and blastocyst scoring correlated with OPR week 12, independently of other factors like BMI and vitrification day of blastocysts (Day 5 or 6).

LIMITATIONS, REASONS FOR CAUTION

In this study, vaginal micronized progesterone pessaries, a solid pessary with progesterone suspended in vegetable hard fat, were used vaginally as well as rectally. It is unknown whether other vaginal progesterone products, such as capsules, gel, or tablet, could be used rectally with the same rescue effect.

WIDER IMPLICATIONS OF THE FINDINGS

A substantial part of HRT-FET patients receiving vaginal progesterone treatment has lowserum P4. Adding rectally administered progesterone in these patients increases the reproductive outcome. Importantly, rectal progesterone administration is considered convenient, and progesterone pessaries are easy to administer rectally and of low cost.

STUDY FUNDING/COMPETING INTEREST(S)

Gedeon Richter Nordic supported the study with an unrestricted grant as well as study medication. B.A. has received unrestricted grant from Gedeon Richter Nordic and Merck and honoraria for lectures from Gedeon Richter, Merck, IBSA and Marckyrl Pharma. P.H. has received honoraria for lectures from Gedeon Richter, Merck, IBSA and U.S.K. has received grant from Gedeon Richter Nordic, IBSA and Merck for studies outside this work and honoraria for teaching from Merck and Thillotts Pharma AB and conference expenses covered by Merck. The other co-authors have no conflict of interest to declare.

TRIAL REGISTRATION NUMBER (25)

EudraCT no.: 2019-001539-29.

In-Vitro Decidualization With Different Progesterone Concentration: Development of a Hormone-Responsive 3D Endometrial Tissue Using Rat Endometrial Tissues

Infertility in women is associated with various uterine and ovarian disorders. Treatment strategies for infertility can range from medications to embryo implantation through assisted reproductive technology (ART). ART has enabled considerable progress; however, there is currently no treatment to replace the endometrium itself. Decidualization requires a complex interaction between endometrial tissue and estrogen and progesterone. We aimed to create a three-dimensional endometrial-like tissue model using in-vitro cell sheet engineering with rat endometrium, and culture cells at different progesterone concentrations to mimic local concentrations. Histological and morphological changes revealed that development of the endometrial-like tissue was not proportional to progesterone concentrations in terms of thickness, number of endometrial glands, or area fraction of intimal glands. These results suggest that decidualization may not be commensurate with the local endometrial progesterone concentration. Notably, the number of endometrial glands increased in the high concentration group and compaction occurred, indicating that the endometrial conditions in the high concentration group may be most conducive to increase pregnancy rates. These findings suggest that there may be an "optimal progesterone concentration" for decidualization, application of which may lead to new strategies for improving pregnancy rates in women with infertility.

Low serum progesterone on day of transfer adversely impacts ongoing pregnancy rates in hormonally prepared single blastocyst frozen embryo transfer cycles

OBJECTIVE

To evaluate if serum progesterone (P) levels on the day of transfer influence ongoing pregnancy rate (OPR) in hormonally prepared single blastocyst frozen embryo transfer (FET) cycles?

STUDY DESIGN

Single center prospective cohort study conducted between June 2021 and August 2022 analyzed 217 single good quality blastocyst FET cycles hormonally prepared with oral estradiol valerate and micronized vaginal progesterone 400 mg twice daily.

RESULTS

Mean serum P on the day of embryo transfer (ET) was 9.76 ± 5.19 ng/ml. Receiver operator curve (ROC) showed a significant predictive value of serum P levels on the day of ET for OPR, with an area under curve (AUC) (95 %CI) = 0.58 (0.49-0.66). Optimal serum P threshold for OPR was 7.7 ng/ml (Sensitivity 76.8%, Specificity 43.7%). 35.9% patients had serum P below this threshold. BMI was significantly higher (26.8 ± 3.7 vs 25.6 ± 4.3; p = 0.048) in patients with serum P < 7.7 ng/ml vs ≥ 7.7 ng/ml. OPR was significantly lower (24.4% vs 45.3%; p = 0.002) and clinical miscarriage rates significantly higher (37.9% vs 19.2%; p = 0.042) if serum P < 7.72 ng/ml vs ≥ 7.7 ng/ml.

CONCLUSION

This study found that serum P level on the day of transfer in hormonally prepared FET cycles was a significant predictor of OPR.

Metabolomics analysis of serum metabolites during endometrial transformation: association with recurrent implantation failure in hormonal replacement therapy-frozen embryo transfers cycles

PURPOSE

The purpose of this study was to investigate alterations in serum metabolites during endometrial transformation and possible associations with recurrent implantation failure (RIF) in hormonal replacement therapy (HRT)-frozen embryo transfer (FET) cycles.

METHODS

We performed a prospective study involving 100 patients scheduled for HRT-FET cycles during January 2022 to April 2022. Blood serum samples were collected on the day of progesterone administration (dPA) and on the third day of progesterone administration (d3PA). Gas chromatography-mass spectrometry (GC-MS) analysis was performed to identify and quantify serum metabolites. A nested case-control study including 19 RIF patients and 19 matching controls was conducted to explore the predictive value of serum metabolites for RIF. Partial least squares discriminant analysis (PLS-DA) and receiver operating characteristic (ROC) curve analysis were performed to establish prediction models.

MAIN RESULTS

We identified 105 serum metabolites, with 76 of them exhibiting significant alterations during the initial 3 days of endometrial transformation. Metabolites involved in amino acid metabolism and tricarboxylic acid (TCA) cycle showed lower levels during endometrial transformation. In the nested case-control study, the prediction model based on the ratio of serum metabolites between d3PA and dPA showed the highest area under the ROC curve (AUC), accuracy, and R2 and Q2 values. Eight metabolites, including indol-3-propionic acid, beta-alanine, myristoleic acid, malic acid, indole, DL-isocitric acid, proline, and itaconic acid, exhibited high predictive values for RIF.

CONCLUSION

This study demonstrates alterations in serum metabolites during endometrial transformation, particularly in amino acid metabolism and TCA cycle. The identified metabolites, especially indol-3-propionic acid and malic acid, show potential as predictive markers for RIF. These findings contribute to a better understanding of the metabolic changes associated with endometrial receptivity and provide insights for the development of personalized approaches to improve implantation outcomes in FET cycles.

Comparison of Dydrogesterone and GnRH-a Effects After Laparoscopic Surgery in Patients with Stage III and IV Endometriosis

Objective

To compare the spontaneous pregnancy rates between dydrogesterone and Gonadotropin-releasing hormone agonist (GnRH-a) treatments in patients with endometriosis stage III and IV after laparoscopy.

Methods

The clinical data of patients with endometriosis stage III and IV administered laparoscopic surgery in our hospital from January 2018 to March 2020 were retrospectively analyzed. Totally 151 cases were divided into two groups according to postoperative medication, including the study (70 cases) and control (81 cases) groups treated with dydrogesterone and GnRH-a, respectively. The spontaneous pregnancy and subsequent pregnancy outcomes were assessed within 12 months.

Results

Totally 49 patients had spontaneous pregnancy. Among them, there were 31 cases in the dydrogesterone group (spontaneous pregnancy rate of 44.3%, 31/70), including 25 live birth cases (35.7%, 25/70), 4 miscarriage cases, and 2 ectopic pregnancy cases. The time to conception was 1-10 months (median value of 5 months). Totally 18 cases in the GnRH-a group had spontaneous pregnancy (22.2%, 18/81), including 16 live birth cases (19.8%, 16/81). 81) and 2 miscarriage cases; the time to conception was 3-11 months (median value of 6 months). There were significant differences in spontaneous pregnancy rate and cumulative spontaneous pregnancy rate between the two groups (P = 0.005 and 0.003, respectively).

Conclusion

Dydrogesterone after laparoscopic surgery in patients with endometriosis stage III and IV improved the natural pregnancy rate.

Elevated serum progesterone levels before frozen embryo transfer do not negatively impact reproductive outcomes: a large retrospective cohort study

OBJECTIVE

To evaluate whether patients with high-serum progesterone levels before frozen embryo transfer (FET) under hormonal replacement therapy present with worse reproductive outcomes.

DESIGN

A cohort retrospective study.

SETTING

A university-affiliated fertility center.

PATIENT(S)

A total of 3,183 FET cycles in patients receiving hormonal replacement therapy between March 2009 and December 2020 were included. The luteal phase was covered with 200 mg per 8 hours of vaginal micronized progesterone either alone or in combination with a daily subcutaneous injection of 25 mg of progesterone. A total of 1,360 cycles corresponded to frozen homologous embryo transfer (ET) (hom-FET), 1,024 were euploid ET (eu-FET) after preimplantation genetic testing for aneuploidies, and 799 cycles were frozen heterologous ET (het-FET). All patients had adequate serum progesterone levels (≥10.6 ng/mL) before the procedure.

INTERVENTION(S)

Frozen embryo transfer cycles.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy, miscarriage, and live birth rates (LBRs).

RESULTS

Median (P25; P75) serum progesterone level before FET was 14.39 (12.43-17.49) ng/mL. Progesterone levels were significantly higher in the group under vaginal plus subcutaneous progesterone (15.96 [13.74-21.60] vs. 14.09 [12.19-16.95]). No differences in clinical pregnancy, miscarriage, and LBR were observed based on the use of vaginal or vaginal plus subcutaneous progesterone for each of the groups (hom-FET, eu-FET, and het-FET). Live birth rates were comparable among patients in the highest centile of serum progesterone levels (≥p90) (22.33 ng/mL) and the rest of the patients (p<90) (43.9% vs. 41.3%). Patients with progesterone levels ≥p90 presented lower body mass index than those in the lower centiles (

CONCLUSIONS

Elevated serum progesterone levels before FET do not impair reproductive outcomes in patients receiving artificially prepared cycles with vaginal or vaginal plus subcutaneous progesterone.

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Key Words

• Serum progesterone levels
• artificial endometrial preparation
• frozen embryo transfer
• hormonal replacement therapy
• luteal phase support

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MESH Headings

• Pregnancy
• Humans
• Female
• Progesterone
• Retrospective Studies
• Abortion, Spontaneous/diagnosis
• Abortion, Spontaneous/etiology
• Embryo Transfer/methods
• Cohort Studies
• Pregnancy Rate
• Live Birth

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Affiliation(s)

Iñaki González-Foruria Department of Obstetrics Gynecology and Reproductive Medicine, Dexeus University Hospital, Barcelona, Spain; Universitat de Vic - Universitat Central de Catalunya, Vic, Spain.
Sandra García Department of Obstetrics Gynecology and Reproductive Medicine, Dexeus University Hospital, Barcelona, Spain
Manuel Álvarez Department of Obstetrics Gynecology and Reproductive Medicine, Dexeus University Hospital, Barcelona, Spain
Annalisa Racca Department of Obstetrics Gynecology and Reproductive Medicine, Dexeus University Hospital, Barcelona, Spain
María Hernández Department of Obstetrics Gynecology and Reproductive Medicine, Dexeus University Hospital, Barcelona, Spain
Nikolaos P Polyzos Department of Obstetrics Gynecology and Reproductive Medicine, Dexeus University Hospital, Barcelona, Spain
Buenaventura Coroleu Department of Obstetrics Gynecology and Reproductive Medicine, Dexeus University Hospital, Barcelona, Spain

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Comparison of the efficacy of subcutaneous versus vaginal progesterone using a rescue protocol in vitrified blastocyst transfer cycles

RESEARCH QUESTION

Does administration of subcutaneous (s.c.) progesterone support ongoing pregnancy rates (OPR) similar to vaginal progesterone using a rescue protocol in hormone replacement therapy frozen embryo transfer cycles?

DESIGN

Retrospective cohort study. Two sequential cohorts - vaginal progesterone gel (December 2019-October 2021; n=474) and s.c. progesterone (November 2021-November 2022; n=249) -were compared. Following oestrogen priming, s.c. progesterone 25 mg twice daily (b.d.) or vaginal progesterone gel 90 mg b.d. was administered. Serum progesterone was measured 1 day prior to warmed blastocyst transfer (i.e. day 5 of progesterone administration). In patients with serum progesterone concentrations <8.75 ng/ml, additional s.c. progesterone (rescue protocol; 25 mg) was provided.

RESULTS

In the vaginal progesterone gel group, 15.8% of patients had serum progesterone <8.75 ng/ml and received the rescue protocol, whereas no patients in the s.c. progesterone group received the rescue protocol. OPR, along with positive pregnancy and clinical pregnancy rates, were comparable between the s.c. progesterone group without the rescue protocol and the vaginal progesterone gel group with the rescue protocol. After the rescue protocol, the route of progesterone administration was not a significant predictor of ongoing pregnancy. The impact of different serum progesterone concentrations on reproductive outcomes was evaluated by percentile (<10th, 10-49th, 50-90th and >90th percentiles), taking the >90th percentile as the reference subgroup. In both the vaginal progesterone gel group and the s.c. progesterone group, all serum progesterone percentile subgroups had similar OPR.

CONCLUSIONS

Subcutaneous progesterone 25 mg b.d. secures serum progesterone >8.75 ng/ml, whereas additional exogenous progesterone (rescue protocol) was needed in 15.8% of patients who received vaginal progesterone. The s.c. and vaginal progesterone routes, with the rescue protocol if needed, yield comparable OPR.

Endometrial receptivity tests in reproduction: a SWOT analysis

Endometrial receptivity and its management in assisted reproduction is now a significant focus of research interest. Endometrial receptivity tests, which analyze different panels of gene expression, are usually offered in fertility clinics to determine the women's individual 'window of implantation', providing a personalized timing for embryo transfer. However, there are still no definite indications on whether its inclusion in the study of the infertile couple or the study of patients with repeated implantation failure is essential.

An integrative analysis of endometrial steroid metabolism and transcriptome in relation to endometrial receptivity in in vitro fertilization patients

OBJECTIVE

To study the relationship between the steroid concentration in the endometrium, in serum, and the gene expression level of steroid-metabolizing enzymes in the context of endometrial receptivity in in vitro fertilization (IVF) patients.

DESIGN

Case-control study of 40 IVF patients recruited in the SCRaTCH study (NTR5342), a randomized controlled trial investigating pregnancy outcome after "endometrial scratching." Endometrial biopsies and serum were obtained from patients with a first failed IVF cycle randomized to the endometrial scratch in the midluteal phase of the natural cycle before the next fresh embryo transfer during the second IVF cycle.

SETTING

University hopsital.

PATIENTS

Twenty women with clinical pregnancy were compared with 20 women who did not conceive after fresh embryo transfer. Cases and controls were matched for primary vs. secondary infertility, embryo quality, and age.

INTERVENTION

None.

MAIN OUTCOME MEASURE(S)

Steroid concentrations in endometrial tissue homogenates and serum were measured with liquid chromatography-mass spectrometry. The endometrial transcriptome was profiled by RNA-sequencing, followed by principal component analysis and differential expression analysis. False discovery rate-adjusted and log-fold change >|0.5| were selected as the threshold for differentially expressed genes.

RESULT(S)

Estrogen levels were comparable in both serum (n = 16) and endometrium (n = 40). Androgens and 17-hydroxyprogesterone were higher in serum than that in endometrium. Although steroid levels did not vary between pregnant and nonpregnant groups, subgroup analysis of primary women with infertility showed a significantly lower estrone concentration and estrone:androstenedione ratio in serum of the pregnant group (n = 5) compared with the nonpregnant group (n = 2). Expression of 34 out of 46 genes encoding the enzymes controlling the local steroid metabolism was detected, and estrogen receptor β gene was differentially expressed between pregnant and nonpregnant women. When only the primary infertile group was considered, 28 genes were differentially expressed between pregnant and nonpregnant women, including HSD11B2, that catalyzes the conversion of cortisol into cortisone.

CONCLUSION(S)

Steroidomic and transcriptomic analyses show that steroid concentrations are regulated by the local metabolism in the endometrium. Although no differences were found in endometrial steroid concentration in the pregnant and nonpregnant IVF patients, primary women with infertility showed deviations in steroid levels and gene expression, indicating that a more homogeneous patient group is required to uncover the exact role of steroid metabolism in endometrial receptivity.

CLINICAL TRIAL REGISTRATION NUMBER

The study was registered in the Dutch trial registry (www.trialregister.nl), registration number NL5193/NTR5342, available at https://trialsearch.who.int/Trial2.aspx?TrialID=NTR6687. The date of registration is July 31, 2015. The first enrollment is on January 1, 2016.

Current Trends on Bioengineering Approaches for Ovarian Microenvironment Reconstruction

Ovarian tissue has a unique microarchitecture and a complex cellular and molecular dynamics that are essential for follicular survival and development. Due to this great complexity, several factors may lead to ovarian insufficiency, and therefore to systemic metabolic disorders and female infertility. Techniques currently used in the reproductive clinic such as oocyte cryopreservation or even ovarian tissue transplant, although effective, have several limitations, which impair their wide application. In this scenario, mimetic ovarian tissue reconstruction comes as an innovative alternative to develop new methodologies for germ cells preservation and ovarian functions restoration. The ovarian extracellular matrix (ECM) is crucial for oocyte viability maintenance, once it acts actively in folliculogenesis. One of the key components of ovarian bioengineering is biomaterials application that mimics ECM and provides conditions for cell anchorage, proliferation, and differentiation. Therefore, this review aims at describing ovarian tissue engineering approaches and listing the main limitations of current methods for preservation and reestablishment of ovarian fertility. In addition, we describe the main elements that structure this study field, highlighting the main advances and the challenges to overcome to develop innovative methodologies to be applied in reproductive medicine. Impact Statement This review presents the main advances in the application of tissue bioengineering in the ovarian tissue reconstruction to develop innovative solutions for ovarian fertility reestablishment.

Individualized luteal phase support using additional oral dydrogesterone in artificially prepared frozen embryo transfer cycles: is it beneficial?

RESEARCH QUESTION

Does additional supplementation with oral dydrogesterone improve reproductive outcomes in patients with low serum progesterone concentrations on the day of frozen embryo transfer (FET) after artificial (HRT) endometrial preparation?

DESIGN

Retrospective, single-centre cohort study including 694 unique patients performing single blastocyst transfer in an HRT cycle. For luteal phase support, intravaginal micronized vaginal progesterone (MVP, 400 mg twice daily) was administered. Serum progesterone concentrations were assessed prior to FET and outco-mes were compared among patients with normal serum progesterone (≥8.8 ng/ml) continuing the routine protocol and patients with low serum progesterone (<8.8 ng/ml) who received additional oral dydrogesterone supplementation (10 mg three times daily) from the day after FET onwards. Primary outcome was live birth rate (LBR), with a multivariate regression model correcting for relevant confounders.

RESULTS

Normal serum progesterone concentrations were observed in 547/694 (78.8%) of patients who continued only MVP as planned, whereas low (<8.8 ng/ml) serum progesterone concentrations were detected in 147/694 (21.2%) patients who received additional oral dydrogesterone supplementation on top of MVP from the day after FET onwards. LBR was comparable between both groups: 37.8% for MVP-only versus 38.8% for MVP+OD (P = 0.84). The multivariate logistic regression model indicated that LBR was not significantly associated with the investigated approaches (adjusted odds ratio 1.01, 95% confidence interval 0.69-1.47, P = 0.97).

CONCLUSIONS

The current findings suggest that additional oral dydrogesterone supplementation in patients with low serum progesterone concentrations at the moment of transfer could have the potential to rescue reproductive outcomes in HRT-FET cycles. This field of research, however, remains hampered by the absence of randomized controlled trials.

Pre-implantation mouse embryo movement under hormonally altered conditions

Pre-implantation embryo movement is crucial to pregnancy success, but the role of ovarian hormones in modulating embryo movement is not understood. We ascertain the effects of altered hormonal environment on embryo location using two delayed implantation mouse models: natural lactational diapause (ND); and artificially induced diapause (AD), a laboratory version of ND generated by ovary removal and provision of supplemental progesterone (P4). Previously, we showed that embryos in a natural pregnancy (NP) first display unidirectional clustered movement, followed by bidirectional scattering and spacing movement. In the ND model, we discovered that embryos are present as clusters near the oviductal-uterine junction for ∼24 h longer than NP, followed by locations consistent with a unidirectional scattering and spacing movement. Intriguingly, the AD model resembles embryo location in NP and not ND. When measuring serum hormone levels, unlike the popular paradigm of reduced estrogen (E2) levels in diapause, we observed that E2 levels are comparable across NP, ND and AD. P4 levels are reduced in ND and highly increased in AD when compared to NP. Further, exogenous administration of E2 or P4 modifies embryo location during the unidirectional phase, while E2 treatment also affects embryo location in the bidirectional phase. Taken together, our data suggest that embryo movement can be modulated by both P4 and E2. Understanding natural hormonal adaptation in diapause provides an opportunity to determine key players that regulate embryo location, thus impacting implantation success. This knowledge can be leveraged to understand pregnancy survival and implantation success in hormonally altered conditions in the clinic.

Adjustment of progesterone administration after endometrial transcriptomic analysis does not improve reproductive outcomes in women with adenomyosis

RESEARCH QUESTION

Do patients with adenomyosis present a dysregulated endometrial receptivity that can be reversed with personalized embryo transfer (PET) by transcriptomic-based progesterone adjustment, improving IVF outcomes?

DESIGN

A multicentre, retrospective, cohort study that transcriptomically analysed the endometrial receptivity of the endometrium in patients with adenomyosis (n = 81) and healthy women (n = 231). Subsequently, implantation, biochemical and clinical miscarriage, and live birth rates between adenomyosis patients with one previous implantation failure using donor oocytes who received (n = 59) or did not receive (n = 66) PET based on endometrial receptivity, were observed to evaluate if adjusted progesterone improves reproductive outcomes of adenomyosis patients.

RESULTS

Patients with adenomyosis significantly presented an altered endometrial receptivity (non-receptive) compared with healthy patients (53.1% versus 37.2%, P = 0.0179), elevating the risk of adenomyosis patients having a non-receptive endometrium 42.59% higher (95% CI 41.50 to 44.45). No significant differences were found in implantation (62.7% versus 78.8%, P = 0.0514), biochemical (13.5% versus 3.9%, P = 0.1223) and clinical (10.8% versus 15.4%, P = 0.7543) miscarriage, or live birth rates (75.7% versus 80.8%, P = 0.6066), in patients with PET compared with those without PET.

CONCLUSIONS

Women with adenomyosis presented an altered expression of genes involved in decidualization, and a higher rate of non-receptive endometrial statuses than controls. Although progesterone is indispensable for implantation, adjusting progesterone before PET, using endometrial transcriptomic signatures, does not improve IVF outcomes in patients with adenomyosis. Other molecular mechanisms beyond progesterone regulation may be involved in implantation failure.

Clinical outcomes of personalized blastocyst embryo transfer after endometrial receptivity analysis: A multicenter, retrospective cohort study

Purpose

To evaluate clinical outcomes after endometrial receptivity analysis (ERA).

Methods

This was a multicenter, retrospective cohort study involving 861 women who underwent ERA testing at certified fertility clinics in Japan, and who received subsequent personalized blastocyst embryo transfers (ET) between 2018 and 2020. Clinical outcomes, including pregnancies, miscarriages, and live births, were evaluated according to receptivity status for ERA.

Results

Mean patient age was 37.7 years (SD = 4.0), and the median number of previous ETs was 2 (interquartile range, 2-3). 41.0% (353/861) of patients were non-receptive for ERA testing. Clinical pregnancy, miscarriage, and live birth rates for personalized blastocyst ET were 44.5% (226/508), 26.1% (59/226), and 26.8% (136/508) for receptive patients, and 43.1% (152/353), 28.3% (43/152), and 28.9% (102/353) for non-receptive patients, all statistically nonsignificant. Multiple logistic regression demonstrated similar nonsignificant associations between receptivity and clinical outcomes. Greater patient age, smoking, and longer duration of infertility were significantly and negatively associated with receptivity, whereas a history of delivery was positively associated and statistically significant.

Conclusions

Clinical outcomes after ERA testing were similar between receptive and non-receptive patients. Further prospective study including an appropriate comparison group are warranted to evaluate the efficacy of ERA testing.

Serum LH Level on the Day of hCG Administration as a Predictor of the Reproductive Outcomes in Ovulation Induction Cycle Frozen-Thawed Embryo Transfer

Purpose: To evaluate the clinical utility of serum luteinizing hormone (LH) level in predicting frozen embryo transfer (FET) outcomes among the patients with an ovulation induction (OI) cycle. Methods: A total of 250 patients who underwent OI cycle frozen-thawed embryo transfer from January 2018 to June 2020 in Drum Tower Hospital affiliated with Nanjing University Medical School were retrospectively analyzed. The primary outcomes were clinical pregnancy rate and the live birth rate. Results: The results showed that a significant difference in Serum LH level on the day of human chorionic gonadotropin (hCG) administration was observed between the clinical pregnancy group and no clinical pregnancy group (p = 0.002), while there was no significant difference between the live birth group and no live birth group (p = 0.06). Multiple logistic regression analysis of factors related to clinical pregnancy showed serum LH level on the day of hCG administration was related to improved clinical pregnancy rate (OR was 1.02, 95% CI: 1.0-1.03, p = 0.02), while serum LH level had no significant effect on live birth rate. The ROC curves revealed the serum LH level was significantly correlated with clinical pregnancy rate and live birth rate; the cut-off point of serum LH level on the day of hCG administration was 8.46 miu/mL for clinical pregnancy rate (AUC 0.609, p = 0.003). Conclusion: In patients with OI FET, serum LH level on the day of hCG administration might be a biomarker for the prediction of clinical pregnancy. The prediction that patients who underwent OI cycle frozen-thawed embryo transfer with serum LH levels below 8.46 mIU /mL might be pregnant appeared to be meaningful.

A case of discrepancy between three ERA tests in a woman with repeated implantation failure complicated by chronic endometritis

BACKGROUND

Endometrial receptivity array (ERA) is used to determine the timing of embryo transfer (ET) synchronized with the window of implantation (WOI). The effectiveness and evaluation of ERAs in women with recurrent implantation failure remain controversial. We report the case of a patient with recurrent implantation failure that raises the issue of reproducibility of ERA tests.

CASE REPORT

A 36-year-old Japanese woman with secondary infertility who had previously given birth failed to conceive after three frozen-thawed embryo transfer (FET) cycles. An ERA test was conducted to confirm the WOI. The first ERA test was performed 125 h after progesterone exposure. The laboratory reported that the endometrium was in a non-receptive (post-receptive) phase, and recommended retesting 101 h after progesterone exposure. A simultaneous chronic endometritis (CE) test showed a score of 3. After the antibiotics administration to treat CE, the second ERA test was performed after 101 h of progesterone exposure. The laboratory reported that the endometrium had not reached the WOI and estimated the WOI to be 113 ± 3 h after progesterone exposure. The third ERA test was performed 113 h after progesterone exposure. The laboratory reported that the endometrium was in a non-receptive (pre-receptive) phase and estimated the WOI to be 137 ± 3 h after progesterone exposure. A CE test performed at the same time as the second and third ERA tests showed a score of 1 for the collected endometrium. According to the third ERA test results, the vitrified-warmed blastocyst was transferred at 137 h of progesterone exposure. Pregnancy was achieved and the patient had an uncomplicated vaginal delivery at 39 weeks. One year later, another pregnancy was achieved after FET at 137 h of progesterone exposure, and the patient delivered at 33 weeks due to an unexpected membrane rupture.

CONCLUSION

Because the results of the ERA test may vary in the presence of CE, CE should be diagnosed simultaneously with or before conducting ERA tests. If CE is diagnosed, ERA testing should be performed after treatment with antimicrobials or other drugs.

The effect of frozen embryo transfer regimen on the association between serum progesterone and live birth: a multicentre prospective cohort study (ProFET)

STUDY QUESTION

What is the association between serum progesterone levels on the day of frozen embryo transfer (FET) and the probability of live birth in women undergoing different FET regimens?

SUMMARY ANSWER

Overall, serum progesterone levels <7.8 ng/ml were associated with reduced odds of live birth, although the association between serum progesterone levels and the probability of live birth appeared to vary according to the route of progesterone administration.

WHAT IS KNOWN ALREADY

Progesterone is essential for pregnancy success. A recent systematic review showed that in FET cycles using vaginal progesterone for endometrial preparation, lower serum progesterone levels (<10 ng/ml) were associated with a reduction in live birth rates and higher chance of miscarriage. However, there was uncertainty about the association between serum progesterone levels and treatment outcomes in natural cycle FET (NC-FET) and HRT-FET using non-vaginal routes of progesterone administration.

STUDY DESIGN SIZE DURATION

This was a multicentre (n = 8) prospective cohort study conducted in the UK between January 2020 and February 2021.

PARTICIPANTS/MATERIALS SETTING METHODS

We included women having NC-FET or HRT-FET treatment with progesterone administration by any available route. Women underwent venepuncture on the day of embryo transfer. Participants and clinical personnel were blinded to the serum progesterone levels. We conducted unadjusted and multivariable logistic regression analyses to investigate the association between serum progesterone levels on the day of FET and treatment outcomes according to the type of cycle and route of exogenous progesterone administration. Our primary outcome was the live birth rate per participant.

MAIN RESULTS AND THE ROLE OF CHANCE

We studied a total of 402 women. The mean (SD) serum progesterone level was 14.9 (7.5) ng/ml. Overall, the mean adjusted probability of live birth increased non-linearly from 37.6% (95% CI 26.3-48.9%) to 45.5% (95% CI 32.1-58.9%) as serum progesterone rose between the 10th (7.8 ng/ml) and 90th (24.0 ng/ml) centiles. In comparison to participants whose serum progesterone level was ≥7.8 ng/ml, those with lower progesterone (<7.8 ng/ml, 10th centile) experienced fewer live births (28.2% versus 40.0%, adjusted odds ratio [aOR] 0.41, 95% CI 0.18-0.91, P = 0.028), lower odds of clinical pregnancy (30.8% versus 45.1%, aOR 0.36, 95% CI 0.16-0.79, P = 0.011) and a trend towards increased odds of miscarriage (42.1% versus 28.7%, aOR 2.58, 95% CI 0.88-7.62, P = 0.086). In women receiving vaginal progesterone, the mean adjusted probability of live birth increased as serum progesterone levels rose, whereas women having exclusively subcutaneous progesterone experienced a reduction in the mean probability of live birth as progesterone levels rose beyond 16.3 ng/ml. The combination of vaginal and subcutaneous routes appeared to exert little impact upon the mean probability of live birth in relation to serum progesterone levels.

LIMITATIONS REASONS FOR CAUTION

The final sample size was smaller than originally planned, although our study was adequately powered to confidently identify a difference in live birth between optimal and inadequate progesterone levels. Furthermore, our cohort did not include women receiving oral or rectal progestogens.

WIDER IMPLICATIONS OF THE FINDINGS

Our results corroborate existing evidence suggesting that lower serum progesterone levels hinder FET success. However, the relationship between serum progesterone and the probability of live birth appears to be non-linear in women receiving exclusively subcutaneous progesterone, suggesting that in this subgroup of women, high serum progesterone may also be detrimental to treatment success.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by CARE Fertility and a doctoral research fellowship (awarded to P.M.) by the Tommy's Charity and the University of Birmingham. M.J.P. is supported by the NIHR Birmingham Biomedical Research Centre. S.F. is a minor shareholder of CARE Fertility but has no financial or other interest with progesterone testing or manufacturing companies. P.L. reports personal fees from Pharmasure, outside the submitted work. G.P. reports personal fees from Besins Healthcare, outside the submitted work. M.W. reports personal fees from Ferring Pharmaceuticals, outside the submitted work. The remaining authors have no conflict of interest to declare.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov: NCT04170517.

Impact of different endometrial preparation protocols before frozen embryo transfer on pregnancy outcomes: a review

The use of frozen embryo transfer cycles has exponentially increased in the last few years. Optimization of endometrial preparation protocols before frozen embryo transfer is mandatory to further improve pregnancy outcomes. This review will focus on the existing literature with regard to the different available endometrial preparation protocols and their impact on pregnancy outcomes. More specifically, we will focus on programmed, natural, and stimulated frozen embryo transfer cycles. The studies performed on this topic are generally of low quality, and only a few well-performed randomized controlled trials have been published. To date, no strong evidence is available to support the use of 1 preparation method over another in terms of pregnancy outcomes. However, robust data have shown a clearly protective effect of natural frozen embryo transfer cycles against long-term obstetric complications, mainly hypertensive disorders of pregnancy and large for gestational age infants. The introduction of individualized luteal phase support in different endometrial preparation protocols is actually gaining a lot of attention and requires further investigation.

Use of the endometrial receptivity array to guide personalized embryo transfer after a failed transfer attempt was associated with a lower cumulative and per transfer live birth rate during donor and autologous cycles

OBJECTIVE

To determine whether personalized embryo transfer (pET) guided by endometrial receptivity array (ERA) test improves reproductive outcomes for fresh embryo transfers (fsETs) or frozen embryo transfers (FETs) during autologous and donor cycles.

DESIGN

A retrospective, observational, multicenter cohort study.

SETTING

University-affiliated in vitro fertilization center.

PATIENT(S)

The study included patients with a single previous failed transfer and yielded 3,239 autologous transfers and 2,133 donor transfers. Among autologous transfers, 255 were pET guided by ERA; among unguided autologous transfers, 1,122 and 1,862 transfers involved fresh or previously frozen embryos, respectively. Among donor transfers, 319 were ERA-guided; among unguided donor transfers, 1,175 and 639 involved fsETs or FETs, respectively.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Primary outcomes were live birth rate per embryo transfer and cumulative live birth rate on consecutive transfers until live birth or cessation of pregnancy. Secondary outcomes were implantation, pregnancy rate, clinical pregnancy rates per embryo transfer, and miscarriage rate per pregnancy.

RESULT(S)

During both autologous or donor transfers, live birth rate and cumulative live birth rate were higher in FET and fsET than in pET groups, even with euploid transfers. Logistic regression analysis, considering possible confounders, indicated patients receiving pET had poorer outcomes than those undergoing FET and fsET in autologous and donor cycles. Implantation, pregnancy, and clinical pregnancy rates were lower in patients undergoing pET.

CONCLUSION(S)

Using ERA to guide pET during either autologous or donor cycles after a failed transfer attempt did not improve reproductive outcomes. Conversely, worse outcomes were detected when ERA was used.

Clinical factors associated with low serum progesterone levels on the day of frozen blastocyst transfer in hormonal replacement therapy cycles

STUDY QUESTION

Which factors are associated with low serum progesterone (P) levels on the day of frozen embryo transfer (FET), in HRT cycles?

SUMMARY ANSWER

BMI, parity and non-European geographic origin are factors associated with low serum P levels on the day of FET in HRT cycles.

WHAT IS KNOWN ALREADY

The detrimental impact of low serum P concentrations on HRT-FET outcomes is commonly recognized. However, the factors accounting for P level disparities among patients receiving the same luteal phase support treatment remain to be elucidated, to help clinicians predicting which subgroups of patients would benefit from a tailored P supplementation.

STUDY DESIGN, SIZE, DURATION

Observational cohort study with 915 patients undergoing HRT-FET at a tertiary care university hospital, between January 2019 and March 2020.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients undergoing single autologous blastocyst FET under HRT using exogenous estradiol and vaginal micronized progesterone for endometrial preparation. Women were only included once during the study period. The serum progesterone level was measured in the morning of the FET, in a single laboratory. Independent factors associated with low serum P levels (defined as ≤9.8 ng/ml, according to a previous published study) were analyzed using univariate and multivariate logistic regression models.

MAIN RESULTS AND THE ROLE OF CHANCE

Two hundred and twenty-six patients (24.7%) had a low serum P level, on the day of the FET. Patients with a serum P level ≤9.8 ng/ml had a lower live birth rate (26.1% vs 33.2%, P = 0.045) and a higher rate of early miscarriage (35.2% vs 21.5%, P = 0.008). Univariate analysis showed that BMI (P < 0.001), parity (P = 0.001), non-European geographic origin (P = 0.001), the duration of infertility (P = 0.018) and the use of oral estradiol for endometrial preparation (P = 0.009) were significantly associated with low serum P levels. Moreover, the proportion of active smokers was significantly lower in the 'low P concentrations' group (P = 0.002). After multivariate analysis, BMI (odds ratio (OR) 1.06 95% CI (1.02-1.11), P = 0.002), parity (OR 1.32 95% CI (1.04-1.66), P = 0.022), non-European geographic origin (OR 1.70 95% CI (1.21-2.39), P = 0.002) and active smoking (OR 0.43 95% CI (0.22-0.87), P = 0.018) remained independent factors associated with serum P levels ≤9.8 ng/ml.

LIMITATIONS, REASONS FOR CAUTION

The main limitation of this study is its observational design, leading to a risk of selection and confusion bias that cannot be ruled out, although a multivariable analysis was performed to minimize this.

WIDER IMPLICATIONS OF THE FINDINGS

Extrapolation of our results to other laboratories, or other routes and/or doses of administering progesterone also needs to be validated. There is urgent need for future research on clinical factors affecting P concentrations and the underlying pathophysiological mechanisms, to help clinicians in predicting which subgroups of patients would benefit from individualized luteal phase support.

STUDY FUNDING/COMPETING INTEREST(S)

No funding/no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Endometrial gland specific progestagen-associated endometrial protein and cilia gene splicing changes in recurrent pregnancy loss

Endometrial glands are essential for fertility, consisting of ciliated and secretory cells that facilitate a suitable uterine environment for embryo implantation. This study sought to determine whether an endometrial gland specific transcriptome and splicing profile are altered in women with recurrent pregnancy loss. Our data provide a comprehensive catalogue of cilia and PAEP gene isoforms and relative exon usage in endometrial glands. We report a previously unannotated endometrial gland cilia transcript GALNT11 and its susceptibility to exon skipping. Key endometrial receptivity gene transcripts are also reported to change in endometrial glands of women with recurrent pregnancy loss. The endometrial gland cilia and PAEP targets identified in this study could be used to identify a perturbed endometrium, isolate causes of recurrent pregnancy loss and develop targeted therapies in personalised medicine.

Endometrial HLA-F expression is influenced by genotypes and correlates differently with immune cell infiltration in IVF and recurrent implantation failure patients

STUDY QUESTION

Is human leukocyte antigen (HLA)-F protein expressed in mid-secretory endometrium, and are its expression levels influenced by HLA-F gene polymorphisms and correlated with the abundance of uterine natural killer (uNK) cells and anti-inflammatory M2 macrophages?

SUMMARY ANSWER

HLA-F protein is expressed in mid-secretory endometrium, and levels are correlated with immune cell infiltration, plasma progesterone concentrations and HLA-F single-nucleotide polymorphisms (SNPs), however, women experiencing recurrent implantation failure (RIF) show differences when compared to women attending their first IVF treatment.

WHAT IS KNOWN ALREADY

The immunomodulatory HLA class Ib molecules HLA-G and HLA-F are expressed on the extravillous trophoblast cells and interact with receptors on maternal immune cells. Little is known regarding HLA-F expression in endometrial stroma and HLA-F function; furthermore, HLA-F and HLA-G SNP genotypes and haplotypes have been correlated with differences in time-to-pregnancy.

STUDY DESIGN, SIZE, DURATION

Primary endometrial stromal cell (ESC) cultures (n = 5) were established from endometrial biopsies from women attending IVF treatment at a fertility clinic. Basic HLA-F and HLA-G protein expression by the ESCs were investigated. A prospective controlled cohort study was performed including 85 women with a history of RIF and 36 control women beginning their first fertility treatment and with no history of RIF. In some analyses, the RIF group was divided into unknown cause, male infertility, female infertility, and both female and male infertility. Endometrial biopsies and blood samples were obtained the day equivalent to embryo transfer in a hormone-substituted cycle.

PARTICIPANTS/MATERIALS, SETTING, METHODS

HLA protein expression by ESCs was characterized using flow cytometry and western blot. In the cohort study, the specific immune markers HLA-F and HLA-G, CD56 and CD16 (NK cells), CD163 (M2 macrophages), FOXP3 (regulatory T cells) and CD138 (plasma cells) were analysed by immunohistochemistry and a digital image analysis system in endometrial biopsies. Endometrial receptivity was assessed by an endometrial receptivity array test (the ERA® test). Endometrial biopsies were examined according to modified Noyes' criteria. SNPs at the HLA-F gene and HLA-G haplotypes were determined.

MAIN RESULTS AND THE ROLE OF CHANCE

HLA-F protein is expressed in the endometrium at the time of implantation. Furthermore, the HLA-F protein levels were different according to the womeńs HLA-F SNP genotypes and diplotypes, which have previously been correlated with differences in time-to-pregnancy. Endometrial HLA-F was positively correlated with anti-inflammatory CD163+ M2 macrophage infiltration and CD56+ uNK cell abundance for the entire cohort. However, this was not the case for CD56+ in the female infertility RIF subgroup. HLA-F levels in the endometrial stroma were negatively correlated with plasma progesterone concentrations in the RIF subgroup with known female infertility. Conversely, HLA-F and progesterone were positively correlated in the RIF subgroup with infertility of the male partner and no infertility diagnosis of the woman indicating interconnections between progesterone, HLA-F and immune cell infiltration. Glandular sHLA-G expression was also positively correlated with uNK cell abundance in the RIF subgroup with no female infertility but negatively correlated in the RIF subgroup with a female infertility diagnosis.

LARGE SCALE DATA

Immunohistochemistry analyses of endometrial biopsies and DNA sequencing of HLA genes. Data will be shared upon reasonable request to the corresponding author.

LIMITATIONS, REASONS FOR CAUTION

The control group of women attending their first IVF treatment had an anticipated good prognosis but was not proven fertile. A significant age difference between the RIF group and the IVF group reflects the longer treatment period for women with a history of RIF. The standardization of hormonal endometrial preparation, which allowed consistent timing of endometrial and blood sampling, might be a strength because a more uniform hormonal background may more clearly show an influence on the immune marker profile and HLA class Ib levels in the endometrium by other factors, for example genetic polymorphisms. However, the immune marker profile might be different during a normal cycle.

WIDER IMPLICATIONS OF THE FINDINGS

The findings further highlight the importance of HLA-F and HLA-G at the implantation site and in early pregnancy for pregnancy success. Diagnostic measures and modulation of the complex interactions between HLA class Ib molecules, maternal immune cells and hormonal factors may have potential to improve fertility treatment.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Region Zealand Health Sciences Research Foundation and the Zealand University Hospital through the ReproHealth Research Consortium ZUH. The authors declared there are no conflicts of interest.

Low Luteal Serum Progesterone Levels Are Associated With Lower Ongoing Pregnancy and Live Birth Rates in ART: Systematic Review and Meta-Analyses

Progesterone plays a key role in implantation. Several studies reported that lower luteal progesterone levels might be related to decreased chances of pregnancy. This systematic review was conducted using appropriate key words, on MEDLINE, EMBASE, and the Cochrane Library, from 1990 up to March 2021 to assess if luteal serum progesterone levels are associated with ongoing pregnancy (OP) and live birth (LB) rates (primary outcomes) and miscarriage rate (secondary outcome), according to the number of corpora lutea (CLs). Overall 2,632 non-duplicate records were identified, of which 32 relevant studies were available for quantitative analysis. In artificial cycles with no CL, OP and LB rates were significantly decreased when the luteal progesterone level falls below a certain threshold (risk ratio [RR] 0.72; 95% confidence interval [CI] 0.62-0.84 and 0.73; 95% CI 0.59-0.90, respectively), while the miscarriage rate was increased (RR 1.48; 95% CI 1.17-1.86). In stimulated cycles with several CLs, the mean luteal progesterone level in the no OP and no LB groups was significantly lower than in the OP and LB groups [difference in means 68.8 (95% CI 45.6-92.0) and 272.4 (95% CI 10.8-533.9), ng/ml, respectively]. Monitoring luteal serum progesterone levels could help in individualizing progesterone administration to enhance OP and LB rates, especially in cycles without corpus luteum.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=139019, identifier 139019.

Individualized luteal phase support based on serum progesterone levels in frozen-thawed embryo transfer cycles maximizes reproductive outcomes in a cohort undergoing preimplantation genetic testing

INTRODUCTION

Low serum progesterone concentration on frozen embryo transfer (FET) day in hormone replacement therapy (HRT) cycles results in lower reproductive outcomes. Recent studies showed the efficiency of a "rescue protocol'' to restore reproductive outcomes in these patients. Here, we compared reproductive outcomes in HRT FET cycles in women with low serum progesterone levels who received individualized luteal phase support (iLPS) and in women with adequate serum progesterone levels who underwent in vitro fertilization for pre-implantation genetic testing for structural rearrangements or monogenic disorders.

DESIGN

This retrospective cohort study included women (18-43 years of age) undergoing HRT FET cycles with pre-implantation genetic testing at Montpellier University Hospital between June 2020 and May 2022. A standard HRT was used: vaginal micronized estradiol (6mg/day) followed by vaginal micronized progesterone (VMP; 800 mg/day). Serum progesterone was measured after four doses of VMP: if <11ng/ml, 25mg/day subcutaneous progesterone or 30mg/day oral dydrogesterone was introduced.

RESULTS

125 HRT FET cycles were performed in 111 patients. Oral/subcutaneous progesterone supplementation concerned 39 cycles (n=20 with subcutaneous progesterone and n=19 with oral dydrogesterone). Clinical and laboratory parameters of the cycles were comparable between groups. The ongoing pregnancy rate (OPR) was 41.03% in the supplemented group and 18.60% in the non-supplemented group (p= 0.008). The biochemical pregnancy rate and miscarriages rate tended to be higher in the non-supplemented group versus the supplemented group: 13.95% versus 5.13% and 38.46% versus 15.79% (p=0.147 and 0.182 respectively). Multivariate logistic regression analysis found that progesterone supplementation was significantly associated with higher OPR ​​ (adjusted OR = 3.25, 95% CI [1.38 - 7.68], p=0.007).

CONCLUSION

In HRT FET cycles, progesterone supplementation in patients with serum progesterone concentration <11 ng/mL after four doses of VMP significantly increases the OPR.

Systematic use of long-acting intramuscular progesterone in addition to oral dydrogesterone as luteal phase support for single fresh blastocyst transfer: A pilot study

OBJECTIVE

The need of luteal support after FET is no longer to be proven. Different routes of progesterone administration are available with interindividual differences in metabolization and serum progesterone levels, the latter being highly correlated with pregnancy and delivery rates. The administration of 2 different routes of progestogen significantly improves success rates in FET. The aim of the current study was to investigate the added value to combine intramuscular administration of progesterone to dydrogesterone in fresh embryo transfer.

METHODS

This is a retrospective study from prospectively collected data. Patient, aged between 18 and 43 years old, had received a fresh blastocyst transfer between January 2021 and June 2021. In the first group, all patients received only oral dydrogesterone 10mg, three times a day, beginning the evening of oocyte retrieval. In the second group, patients received, in addition to dydrogesterone, a weekly intramuscular injection of progesterone started the day of embryo transfer. Primary endpoint was ongoing pregnancy rate.

RESULTS

171 fresh single blastocyst transfers have been performed during this period. 82 patients were included in "dydrogesterone only" and 89 patients in "dydrogesterone + IM". Our two groups were comparable except for body mass index. After adjustment on BMI, our two groups were comparable regarding implantation rate, early pregnancy rate (46.1 versus 54.9, OR 1.44 [0.78; 2.67], p=0.25) miscarriage rate, ongoing pregnancy rate (30.3 versus 43.9, OR 1.85 [0.97; 3.53] p= 0.06).

CONCLUSION

Using systematically long acting intramuscular progesterone injection in addition to oral dydrogesterone as luteal phase support seems to have no significant impact on IVF outcomes when a single fresh blastocyst transfer is performed.

GnRH agonist supplementation in hormone replacement therapy-frozen embryo transfer cycles: a randomized controlled trial

RESEARCH QUESTION

Will two boluses of gonadotrophin-releasing hormone agonist (GnRHa) during hormone replacement therapy-frozen embryo transfer (HRT-FET) cycles reduce the total pregnancy loss rate?

DESIGN

Randomized controlled trial including a total of 287 HRT-FET cycles performed between 2013 and 2019. After randomization participants allocated to the GnRHa group (n = 144) underwent a standard HRT protocol, supplemented with a total of two boluses of triptorelin 0.1 mg; one bolus 2 days before starting vaginal progesterone and one bolus on the 7th day of progesterone. The control group (n = 143) underwent a standard HRT-FET protocol only.

RESULTS

The intention-to-treat analysis showed no significant difference in total pregnancy loss between the GnRHa group and the control group (21% versus 33%; relative risk [RR] 0.63, 95% confidence interval [CI] 0.35-1.11), nor was the biochemical pregnancy loss per positive human chorionic gonadotrophin (HCG) significantly lower in the GnRHa group (12%, 8/67) compared with the control group (25%, 18/72) (RR 0.48, 95% CI 0.22-1.02). Participants with a live birth had a significantly higher mean progesterone concentration compared with participants without a live birth (25.0 ± 12.2 versus 23.8 ± 8.9 nmol/l; P = 0.001). Furthermore, a trend for a higher live birth rate (LBR) correlated with the highest oestradiol quartile concentration (oestradiol >0.957 nmol/l).

CONCLUSIONS

Although a difference of 14% in biochemical loss and 12% in total pregnancy loss in favour of GnRHa supplementation was seen this did not reach statistical difference. Luteal progesterone and oestradiol concentrations correlate with LBR in the HRT-FET cycle, emphasizing the importance of luteal serum progesterone and oestradiol monitoring.

Key to Life: Physiological Role and Clinical Implications of Progesterone

The most recent studies of progesterone research provide remarkable insights into the physiological role and clinical importance of this hormone. Although the name progesterone itself means “promoting gestation”, this steroid hormone is far more than a gestational agent. Progesterone is recognized as a key physiological component of not only the menstrual cycle and pregnancy but also as an essential steroidogenic precursor of other gonadal and non-gonadal hormones such as aldosterone, cortisol, estradiol, and testosterone. Based on current findings, progesterone and novel progesterone-based drugs have many important functions, including contraception, treatment of dysfunctional uterine bleeding, immune response, and prevention of cancer. Considering the above, reproduction and life are not possible without progesterone; thus, a better understanding of this essential molecule could enable safe and effective use of this hormone in many clinical conditions.