Endometrial development and function in experimentally induced luteal phase deficiency

Association between proliferative-to-secretory endometrial compaction and pregnancy outcomes after embryo transfer: a systematic review and meta-analysis

STUDY QUESTION

Does the change in endometrial thickness (EMT) from the end of the follicular/estrogen phase to the day of embryo transfer (ET) determine subsequent pregnancy outcomes?

SUMMARY ANSWER

Endometrial compaction from the late-proliferative to secretory phase is not associated with live birth rate (LBR) and other pregnancy outcomes.

WHAT IS KNOWN ALREADY

Endometrial compaction has been suggested to be indicative of endometrial responsiveness to progesterone, and its association with ET outcome has been investigated but is controversial.

STUDY DESIGN, SIZE, DURATION

A systematic review with meta-analysis was carried out. PubMed, EMBASE, and Web of Science were searched to identify relevant studies from inception to 18 November 2022. The reference lists of included studies were also manually screened for any additional publications.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Cohort studies comparing ET pregnancy outcomes between patients with and without endometrial compaction were included. A review of the studies for inclusion, data extraction, and quality assessment was performed by two independent reviewers. The effect size was synthesized as odds ratio (OR) with 95% CI using a random-effects model. Heterogeneity and publication bias were assessed by the I2 statistic and Egger's test, respectively. The primary outcome was LBR. Secondary outcomes included biochemical pregnancy rate (BPR), clinical pregnancy rate (CPR), miscarriage rate (MR), ongoing pregnancy rate (OPR), and ectopic pregnancy rate (EPR).

MAIN RESULTS AND THE ROLE OF CHANCE

Seventeen cohort studies involving 18 973 ET cycles fulfilled the eligibility criteria. The pooled results revealed that there were no significant differences between endometrial compaction and non-compaction groups in LBR (crude OR (cOR) = 0.95, 95% CI 0.87-1.04; I2 = 0%; adjusted OR (aOR) = 1.02, 95% CI 0.87-1.19, I2 = 79%), BPR (cOR = 0.93, 95% CI 0.81-1.06; I2 = 0%; aOR = 0.88, 95% CI 0.75-1.03, I2 = 0%), CPR (cOR = 0.98, 95% CI 0.81-1.18; I2 = 70%; aOR = 0.86, 95% CI 0.72-1.02, I2 = 13%), MR (cOR = 1.09, 95% CI 0.90-1.32; I2 = 0%; aOR = 0.91, 95% CI 0.64-1.31; I2 = 0%), and EPR (cOR = 0.70, 95% CI 0.31-1.61; I2 = 61%). The OPR was marginally higher in crude analysis (cOR = 1.48, 95% CI 1.01-2.16; I2 = 81%) among women with compacted endometrium, but was not evident in adjusted results (aOR = 1.36, 95% CI 0.86-2.14; I2 = 84%). Consistently, the pooled estimate of LBR remained comparable in further subgroup and sensitivity analyses according to the degree of compaction (0%, 5%, 10%, 15%, or 20%), type of ET (fresh, frozen, or euploid only), and endometrial preparation protocol (natural or artificial). No publication bias was observed based on Egger's test.

LIMITATIONS, REASONS FOR CAUTION

Although the number of included studies is sufficient, data on certain measures, such as EPR, are limited. The inherent bias and residual confounding were also inevitable owing to the observational study design. Furthermore, inconsistent definitions of pregnancy outcomes may affect the accuracy of our pooled analysis.

WIDER IMPLICATIONS OF THE FINDINGS

Given the lack of prognostic value, assessing endometrial compaction or repeated EMT measurement on the day of ET may not be necessary or warranted.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by Natural Science Foundation of Jiangxi Province (20224BAB216025), National Natural Science Foundation of China (82260315), and Central Funds Guiding the Local Science and Technology Development (20221ZDG020071). The authors have no conflicts of interest to declare.

REGISTRATION NUMBER

CRD42022384539 (PROSPERO).

Can endometrial compaction predict live birth rates in assisted reproductive technology cycles? A systematic review and meta-analysis

PURPOSE

Endometrial compaction (EC) is defined as the difference in endometrial thickness from the end of the follicular phase to the day of embryo transfer (ET). We aimed to determine the role of EC in predicting assisted reproductive technology (ART) success by conducting a meta-analysis of studies reporting the association between EC and clinical outcomes of ART.

METHODS

MEDLINE via PubMed, Web of Science, Scopus, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched from the date of inception to May 19, 2023. The primary outcome was live birth rate (LBR) per ET. Secondary outcomes were live birth or ongoing pregnancy per ET, ongoing pregnancy per ET, clinical pregnancy per ET, and miscarriage per clinical pregnancy.

RESULTS

Fifteen studies were included. When data from all studies reporting live birth were pooled, overall LBR rates were comparable in cycles showing EC or not [RR = 0.97, 95%CI = 0.92 to 1.02; 10 studies, 11,710 transfer cycles]. In a subgroup of studies that included euploid ET cycles, a similar LBR for patients with and without EC was noted [RR = 0.99, 95%CI = 0.86 to 1.13, 4 studies, 1172 cycles]. The miscarriage rate did not seem to be affected by the presence or absence of EC [RR = 1.06, 95%CI = 0.90 to 1.24; 12 studies].

CONCLUSION

The predictive value of EC in determining LBR is limited, and assessment of EC may no longer be necessary, given these findings.

TRIAL REGISTRATION

PROSPERO CRD42023410389.

Endometrial compaction is associated with the outcome of artificial frozen-thawed embryo transfer cycles: a retrospective cohort study

INTRODUCTION

The relationships between the outcome of frozen-thaw embryo transfer (FET) cycle and endometrial compaction were not quite consistent.

OBJECTIVE

To analyze the relationship between the outcome of FET cycle and endometrial compaction.

MATERIALS AND METHODS

A total of 1420 women using FET were researched. The change in endometrial thickness on ET day and those on the day of progesterone (P) administration start is the basis for grouping. Group 1 was endometrial compaction group, and group 2 was the endometrial non-compaction group. Outcome measure was clinical pregnancy, estradiol (E₂) levels, progesterone (P) levels, endometrial morphology, and thickness in each period of FET cycle.

RESULTS

A significantly lower clinical pregnancy rate was observed in group 2 in comparison with group 1 (43.4% vs. 55.1%, P < 0.01). In addition, P levels on the day of P administration start were lower in group 2 (0.73 ± 0.93 ng/ml vs. 0.90 ± 1.85 ng/ml, P = 0.006), while E₂ levels on ET day were higher in group 2 (316.42 ± 304.95 pg/ml vs. 257.88 ± 219.15 pg/ml, P = 0.001) than in group 1. The binary logistic regression analysis showed a lower rate of clinical pregnancy in group 2 (aOR = 0.617, 95% CI 0.488-0.779, P = 0.001).

CONCLUSIONS

Clinical pregnancy rates were significantly higher in women with endometrial compaction on ET day compared to women with no changes or thickening. Therefore, we recommend paying closer attention to endometrial compaction in women undergoing FET as a method to estimate endometrial receptivity.

Investigating the impact of endometrial compaction on clinical pregnancy rate in artificial frozen-thawed embryo transfer cycles

Objective: The aim of our study was to evaluate sonographic endometrial thickness succeeding the estrogen-only stage and on the day when embryo transfer (ET) occurred in artificial frozen embryo transfer (FET) cycles to delve into the effect of endometrial compaction (EC) on clinical pregnancy rate (CPR). Patients and Methods: In the first group endometrial thickness diminished when ET occurred when compared to the end of the estrogen-only phase (n:37). Endometrial thickness increased/did not alter for the second group (n:70). Demographic characteristics were recorded and the following were studied: in vitro fertilization (IVF) treatment indications, hormone levels, total antral follicle count, duration of infertility, embryo quality, embryo-fundus distance, endometrial thickness at the end of estrogen-only phase and on ET day, luteal support, CPR. Results: No significant difference occurred in CPRs (n:107). ET, on day 5 was higher in the first group (p

Activation function 1 of progesterone receptor is required for progesterone antagonism of oestrogen action in the uterus

BACKGROUND

Progesterone receptor (PGR) is a master regulator of uterine function through antagonistic and synergistic interplays with oestrogen receptors. PGR action is primarily mediated by activation functions AF1 and AF2, but their physiological significance is unknown.

RESULTS

We report the first study of AF1 function in mice. The AF1 mutant mice are infertile with impaired implantation and decidualization. This is associated with a delay in the cessation of epithelial proliferation and in the initiation of stromal proliferation at preimplantation. Despite tissue selective effect on PGR target genes, AF1 mutations caused global loss of the antioestrogenic activity of progesterone in both pregnant and ovariectomized models. Importantly, the study provides evidence that PGR can exert an antioestrogenic effect by genomic inhibition of Esr1 and Greb1 expression. ChIP-Seq data mining reveals intermingled PGR and ESR1 binding on Esr1 and Greb1 gene enhancers. Chromatin conformation analysis shows reduced interactions in these genes' loci in the mutant, coinciding with their upregulations.

CONCLUSION

AF1 mediates genomic inhibition of ESR1 action globally whilst it also has tissue-selective effect on PGR target genes.

Endometrial compaction is associated with increased clinical and ongoing pregnancy rates in unstimulated natural cycle frozen embryo transfers: a prospective cohort study

PURPOSE

To investigate the association between endometrial compaction and pregnancy rates in unstimulated natural cycle frozen embryo transfers.

DESIGN

A single-center prospective cohort study. Endometrial thickness by transvaginal ultrasound and blood progesterone levels on the day of ovulation and the day of embryo transfer were evaluated in patients undergoing natural cycle frozen embryo transfer. Compaction was defined as > 5% decrease in endometrial thickness between ovulation day and day of transfer. Clinical and ongoing pregnancy rates in cycles with and without compaction were compared.

RESULTS

Seventy-one women were included, of which 44% had endometrial compaction, with similar rates when subdividing the patients by day of transfer (day 3 or day 5). Clinical and ongoing pregnancy rates were higher in the compaction group compared to the non-compaction group (0.58 vs. 0.16, P < 0.001; 0.52 vs. 0.13, P < 0.001 respectively). Subdividing by degree of compaction > 10% and > 15% revealed similar pregnancy rates as > 5%, with no added benefit to higher degrees of compaction.

CONCLUSIONS

About half the patients in our study undergoing unstimulated natural cycle frozen embryo transfer experienced compaction of the endometrium, occurring as early as day 3 post-ovulation. This was significantly correlated with increased clinical and ongoing pregnancy rates.

Evaluation of endometrial receptivity and implantation failure

PURPOSE OF REVIEW

To succinctly review the basic mechanisms of implantation and luteal phase endometrial differentiation, the etiologies of impaired endometrial function and receptivity, and the current methods that exist to evaluate and treat impaired endometrial receptivity.

RECENT FINDINGS

Human embryo implantation requires bidirectional communication between blastocyst and a receptive endometrium. Etiologies of impaired endometrial receptivity are varied. Some of these include delayed endometrial maturation, structural abnormalities, inflammation, and progesterone resistance. Current methods to evaluate endometrial receptivity include ultrasonography, hysteroscopy, and endometrial biopsy. Treatments are limited, but include operative hysteroscopy, treatment of endometriosis, and personalized timing of embryo transfer.

SUMMARY

Although some mechanisms of impaired endometrial receptivity are well understood, treatment options remain limited. Future efforts should be directed towards developing interventions targeted towards the known mediators of impaired endometrial receptivity.

Transcriptomic Analysis Reveals Endometrial Dynamics in Normoweight and Overweight/Obese Polycystic Ovary Syndrome Women

The aim of this work was to identify the transcriptomic characteristics of the endometrium in normoweight and overweight/obese polycystic ovary syndrome (PCOS) potentially underlying the pathogenesis. This study included 38 patients undergoing in vitro fertilization: 22 women with PCOS and 16 matched controls. Each of the groups was subdivided into normoweight (body mass index (BMI) < 25 kg/m²) and overweight/obese (BMI ≥25 kg/m²) subgroups. Endometrium samples were collected in the secretory phase from controls or in a modeled secretory phase using daily administration of progesterone from women with PCOS before in vitro fertilization treatment. Transcriptome profiles were assessed by high-throughput RNA sequencing to investigate distinct endometrial gene expression patterns in PCOS. Bioinformatics analyses revealed that the endometrium from PCOS expresses significantly different transcripts encoding endometrial receptivity, inflammatory response, angiogenesis, and energy metabolism. Additionally, our study demonstrated that the differentially expressed genes between normoweight and overweight/obese PCOS are involved in fatty acid metabolism, endometrial decidualization, and immune response. For the first time, we have described the transcriptome characteristics of normoweight and overweight/obese PCOS endometria. Our results indicate different endometrial gene expressions between different subtypes of PCOS and non-PCOS women, which might affect endometrial functions in PCOS patients.

Non-Invasive and Mechanism-Based Molecular Assessment of Endometrial Receptivity During the Window of Implantation: Current Concepts and Future Prospective Testing Directions

Suboptimal endometrial receptivity and altered embryo-endometrial crosstalk account for approximately two-thirds of human implantation failures. Current tests of the window of implantation, such as endometrial thickness measurements and the endometrial receptivity assay, do not consistently improve clinical outcomes as measured by live birth rates. Understanding the mechanisms regulating the endometrial receptivity during the window of implantation is a critical step toward developing clinically meaningful tests. In this narrative review, the available literature is evaluated regarding mechanisms that regulate the endometrial receptivity during the window of implantation and the current tests developed. Overall, both animal and human studies point to five possible and interrelated mechanisms regulating the endometrial window of implantation: suitable synchrony between endometrial cells, adequate synchrony between the endometrium and the embryo, standard progesterone signaling and endometrial responses to progesterone, silent genetic variations, and typical morphological characteristics of the endometrial glands. The biological basis of current clinical markers or tests of window of implantation is poor. Future studies to elucidate the mechanisms shaping the window of implantation and to investigate the potential markers based on these mechanisms are required. In addition, molecular testing of the endometrium at single-cell resolution should be an initial step toward developing clinically meaningful tests for the optimal window of implantation. As understanding of the optimal window of implantation continues to evolve, one can envision the future development of non-invasive, mechanism-based testing of the window of implantation.

Towards an Improved Understanding of the Effects of Elevated Progesterone Levels on Human Endometrial Receptivity and Oocyte/Embryo Quality during Assisted Reproductive Technologies

Ovarian stimulation is an indispensable part of IVF and is employed to produce multiple ovarian follicles. In women who undergo ovarian stimulation with gonadotropins, supraphysiological levels of estradiol, as well as a premature rise in progesterone levels, can be seen on the day of hCG administration. These alterations in hormone levels are associated with reduced embryo implantation and pregnancy rates in IVF cycles with a fresh embryo transfer. This article aims to improve the reader’s understanding of the effects of elevated progesterone levels on human endometrial receptivity and oocyte/embryo quality. Based on current clinical data, it appears that the premature rise in progesterone levels exerts minimal or no effects on oocyte/embryo quality, while advancing the histological development of the secretory endometrium and displacing the window of implantation. These clinical findings strongly suggest that reduced implantation and pregnancy rates are the result of a negatively affected endometrium rather than poor oocyte/embryo quality. Understanding the potential negative impact of elevated progesterone levels on the endometrium is crucial to improving implantation rates following a fresh embryo transfer. Clinical studies conducted over the past three decades, many of which have been reviewed here, have greatly advanced our knowledge in this important area.

Beyond the uterine first pass: optimizing programmed frozen embryo transfers. A mini-review

With the greatly increased popularity of segmented in vitro fertilization and frozen embryo transfers, progesterone replacement strategies in programmed cycles are being reexamined. Bidirectionality and the limited capacity of the uterine first pass provide an explanation for disconnects between the endometrial and serum levels when either vaginal or intramuscular progesterone is used alone. Whereas monotherapy departs from the physiology of spontaneous pregnancies, combined therapy provides physiologic replacement while minimizing the number of injections.

Endometrial Dating Method Detects Individual Maturation Sequences During the Secretory Phase

BACKGROUND/AIM

This study assessed whether a new immunohistochemical dating method allows precise endometrial dating allowing optimal timing for embryo transfer.

PATIENTS AND METHODS

A novel method was used for endometrial dating, with parameters including menstrual cycle days, Noyes histological criteria, along with immunohistochemical expression pattern of estrogen and progesterone receptors and proliferation marker Ki-67. Endometrial maturation was analyzed on days +5 to +10 after ovulation or progesterone administration in 217 biopsies from 151 subfertile patients during the secretory phase.

RESULTS

Endometrial maturation varied individually, occurring 1.68±1.67 days late. Comparison of histological maturation with clinical days after ovulation showed a delay of about 2 days.

CONCLUSION

Endometrial maturation requires 8 days, rather than the expected 6 days, to reach the histological mid-secretory phase. This is not a delay and is also seen in fertile patients. The new analysis method used is superior to that using Noyes criteria alone and provides a better basis for determining conditions for optimal timing of embryo transfers.

Varying levels of serum estradiol do not alter the timing of the early endometrial secretory transformation

STUDY QUESTION

Do supraphysiologic estradiol (E2) levels in the ranges attained during normal and high response superovulation cycles modify the onset of endometrial secretory transformation?

SUMMARY ANSWER

Highly supraphysiologic levels of E2 do not alter the ability of physiologic levels of progesterone (P4) to induce secretory transformation.

WHAT IS KNOWN ALREADY

Previous studies have demonstrated that premature P4 elevations during IVF cycles are associated with a decrement in clinical pregnancy rates after fresh embryo transfer due to shifts in the window of implantation (WOI). However, alterations in the onset of secretory transformation may not apply uniformly to all patients. High responders with supraphysiologic E2 levels accompanied by similar subtle increases in P4 have not been shown to have decreased sustained implantation rates. This prospective investigation in which whole-genome transcriptomic and methylomic analysis of the endometrium is performed for individual patients under a range of E2 concentrations brings clarity to a long-debated issue.

STUDY DESIGN, SIZE, DURATION

A randomized, prospective and paired trial was conducted in which 10 participants were enrolled and randomized to the order in which they completed three distinct uterine stimulation cycles, each at a specific E2 concentration: physiologic (∼180 pg/ml), moderately supraphysiologic (600-800 pg/ml) or supraphysiologic (2000 pg/ml). Target E2 ranges were selected to mimic those seen in natural, controlled ovarian stimulation and IVF cycles. E2 valerate was administered in order to maintain stable E2 levels for 12 days followed by intramuscular P4 in oil 10 mg/day for two doses, after which an endometrial biopsy was performed. A total of 30 endometrial biopsies were included in a whole-genome transcriptomic and methylomic analysis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Healthy volunteers without a history of infertility were included in this study at a single large infertility center. DNA was isolated from the endometrial biopsy specimens and bisulfite sequencing was performed to construct a methylation array. Differential methylation analysis was conducted based on differences in M-values of individuals across treatment groups for each probe as well as carrying out t-tests. RNA was isolated for RNA-Seq analysis and gene expression values were compared using DESeq2. All analyses were performed in a pairwise fashion to compare among the three stimulation cycles within individuals and secondarily to compare all participants in each of the cycles.

MAIN RESULTS AND THE ROLE OF CHANCE

The mean peak E2 and P4 levels were 275 pg/ml and 4.17 ng/ml in the physiologic group, 910 pg/ml and 2.69 ng/ml in the moderate group was, and 2043 pg/ml and 2.64 ng/ml in the supraphysiologic group, respectively. Principal component analysis of 834 913 CpG sites was performed on M-values of individuals within the low, moderate and supraphysiologic conditions in a paired approach. There were no differences in genome-wide methylation within participants across E2 groups. A paired analysis revealed that gene expression profiles did not differ within the same individual at each of the three E2 levels. No significant alterations in gene expression as related to endometrial physiology were identified between the low, moderate and supraphysiologic groups in an inter-participant analysis.

LIMITATIONS, REASONS FOR CAUTION

Although each participant completed a physiologic cycle in which E2 levels were maintained in a range that would simulate a natural cycle, our findings are limited by lack of an unmedicated control to assess if there was a potential effect from E2V. Additionally, our results were obtained in fertile individuals, who may have a different endometrial response compared to an infertile population. Despite the whole genomic endometrial assessment and rigorous, paired study design, the sample size was limited.

WIDER IMPLICATIONS OF THE FINDINGS

Given that the endometrial response to P4 is unaffected by E2 levels in the supraphysiologic range, diminutions in implantation seen in stimulated cycles may result from embryonic-endometrial dyssynchrony following early P4 elevations or slowly blastulating embryos, which occur independently of the magnitude of the E2 rise.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the Foundation for Embryonic Competence, Basking Ridge, NJ, USA. Dr E.S. reports consultancy work for The Foundation for Embryonic Competence, Basking Ridge, NJ, USA. The other authors declare no conflict of interests related to this topic.

TRIAL REGISTRATION NUMBER

NCT02458404.

Low progesterone levels on the day before natural cycle frozen embryo transfer are negatively associated with live birth rates

STUDY QUESTION

Are progesterone (P) levels on the day before natural cycle frozen embryo transfer (NC-FET) associated with live birth rate (LBR)?

SUMMARY ANSWER

Regular ovulatory women undergoing NC-FET with serum P levels <10 ng/ml on the day before blastocyst transfer have a significantly lower LBR than those with serum P levels >10 ng/ml.

WHAT IS KNOWN ALREADY

The importance of serum P levels around the time of embryo transfer in patients undergoing FET under artificial endometrial preparation has been well established. However, no study has analyzed the importance of serum P levels in patients undergoing FET under a true natural endometrial preparation cycle.

STUDY DESIGN, SIZE, DURATION

This was a retrospective cohort study including 294 frozen blastocyst transfers under natural cycle endometrial preparation at a university-affiliated fertility centre between January 2016 and January 2019.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All patients had regular menstrual cycles and underwent NC-FET with their own oocytes. Only patients who had undergone serum P measurement between 8 am and 11 am on the day before FET were included. Patients did not receive any external medication for endometrial preparation or luteal phase support. Patients were divided into two groups according to serum P levels below or above 10 ng/ml on the day before FET. Univariate analysis was carried out to describe and compare the cycle characteristics with reproductive outcomes. To evaluate the effect of P, a multivariable logistic model was fitted for each outcome after adjusting for confounding variables.

MAIN RESULTS AND THE ROLE OF CHANCE

Mean serum P levels on the day before FET were significantly higher in patients who had a live birth compared to those who did not (14.5 ± 7.0 vs 12.0 ± 6.6 ng/ml, 95% CI [0.83; 4.12]). The overall clinical pregnancy rate (CPR) and LBR were 42.9% and 35.4%, respectively. Patients in the higher P group (>10 ng/ml) had a higher LBR (41.1% vs 25.7%: risk difference (RD) 15.4%, 95% CI [5; 26]) and CPR (48.6% vs 33.0%: RD 15.6%, 95% CI [4; 27]). Patients with higher serum P levels on the day before FET (63% of patients) had an improved LBR (odds ratio: 1.05; 95% CI [1.02; 1.09]). Women with serum P levels <10 ng/ml on the day before FET (37% of patients) had significantly higher weights (62.5 ± 9.9 vs 58.1 ± 7.1 kg, 95% CI [1.92; 6.90]) and BMI (22.9 ± 3.6 vs 21.6 ± 2.7 kg/m2, 95% CI [0.42; 2.25]) compared to patients with P levels >10 ng/ml.

LIMITATIONS, REASONS FOR CAUTION

The main limitation of our study is its retrospective design. Other potential limitations are the detection of LH surge through urine testing and the inclusion of patients who did and did not undergo preimplantation genetic testing for aneuploidies. The protocol used in our institution for monitoring NC-FET does not look for the onset of progesterone secretion by the corpus luteum, and a slow luteinisation process or delay of corpus luteum function cannot be ruled out.

WIDER IMPLICATIONS OF THE FINDINGS

We provide evidence that a minimum serum P threshold (P >10 ng/ml) might be required for improved reproductive outcomes in NC-FET. This result suggests that there are different mechanisms by which P is produced and/or distributed by each patient. This study also provides an excellent model to evaluate the impact of luteal phase defect through NC-FET. A prospective evaluation to assess whether P supplementation should be individualised according to patient's needs is necessary to support our findings.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was used, and there are no competing interests.

Endometrial Receptivity Analysis (ERA) test: an unproven technology

This article addresses the limitations of the endometrial receptivity array (ERA) methodology to increase implantation. Such limitations vary from the assumed inconsistency of the endometrial biopsy, the variable number of genes found to be dysregulated in endometrium samples without the embryonal-induced effect, the failure to account for the simultaneous serum progesterone level, and the expected low percentage of patients who may need this add-on procedure, to the difficulties in synchronising the endometrium with hormone replacements in successive cycles and the inherent perinatal risks associated with routine cryopreservation of embryos. Without a gold standard to compare, the claim that the window of implantation (WOI) might be off by ±12 h only requires a good argument for the advantage it provides to human procreation, knowing that embryos can linger for days before actual embedding starts and that the window is actually a few days. The intra-patient variations in the test need to be addressed. In summary, like all other add-ons, it is doubtful whether the ERA test use can significantly enhance implantation success rates.

Diagnosis and treatment of luteal phase deficiency: a committee opinion

Luteal phase deficiency (LPD) is a clinical diagnosis associated with an abnormal luteal phase length of ≤10 days. Potential etiologies of LPD include inadequate progesterone duration, inadequate progesterone levels, or endometrial progesterone resistance. LPD has not only been described in association with medical conditions but also in fertile, normally menstruating women. Although progesterone is important for the process of implantation and early embryonic development, LPD has not been proven to be an independent entity causing infertility or recurrent pregnancy loss. Controversy exists regarding the multiple proposed measures for diagnosing LPD and, assuming it can be diagnosed accurately, whether treatment improves outcomes. This document replaces the document entitled "Current clinical irrelevance of luteal phase deficiency: a committee opinion," last published in 2015 (Fertil Steril 2015;103:e27-e32).

Female reproductive function after treatment of childhood acute lymphoblastic leukemia

BACKGROUND

The aim was to evaluate self-reported reproductive characteristics and markers of ovarian function in a nationwide cohort of female survivors of childhood acute lymphoblastic leukemia (ALL), because prior investigations have produced conflicting data.

PROCEDURE

Self-reported reproductive characteristics were assessed by questionnaire among 357 adult 5-year survivors, treated between 1964 and 2002, and 836 controls. Ovarian function was assessed by serum levels of anti-Müllerian hormone (AMH), follicle-stimulating hormone (FSH), and inhibin B and by antral follicle count (AFC). Differences between controls and (subgroups of) survivors (total group, chemotherapy [CT]-only group, CT and radiotherapy [RT] group) were analyzed.

RESULTS

Survivors treated with CT only do not differ from controls regarding timing of menarche, virginity status, desire for children, or pregnancy rates. Compared to controls, the CT+RT group was at significantly increased risk of a younger age at menarche (P < .01), virginity, an absent desire for children, and lower pregnancy rates (odds ratio [OR] [95% CI]: 0.3 [CI 0.1-0.6], 0.5 [0.3-0.9], and 0.4 [0.2-0.9], respectively). Survivors in the CT-only group were significantly younger at the birth of their first child. Pregnancy outcomes were not significantly different between any (sub)groups. Survivors treated with total body irradiation (TBI) or hematopoietic stem cell transplantation (HSCT) are at increased risk of abnormal markers of ovarian function.

CONCLUSION

Reproductive function of ALL survivors treated with CT only does not differ from controls. However, survivors additionally treated with RT seem to be at an increased risk of certain adverse reproductive outcomes. Providing personalized counseling about (future) reproductive health risks in this group is imperative.

Therapeutic Potentials of Low-Dose Tacrolimus for Aberrant Endometrial Features in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a major anovulatory infertility affecting a great proportion of women of childbearing age and is associated with obesity, insulin resistance and chronic inflammation. Poor endometrial receptivity and recurrent implantation failure are major hurdles to the establishment of pregnancy in women with PCOS. The accumulating body of evidence obtained from experimental and clinical studies suggests a link between inherent adaptive and innate immune irregularities and aberrant endometrial features in PCOS. The use of conventional therapeutic interventions such as lifestyle modification, metformin and ovarian stimulation has achieved limited clinical success in restoring ovulation and endometrial receptivity in women with PCOS. Unlike other immunosuppressive drugs prescribed in the clinical management of autoimmune and inflammatory disorders that may have deleterious effects on fertility and fetal development, preclinical studies in mice and in women without PCOS but with repeated implantation failure revealed potential therapeutic benefits for the use of low-dose tacrolimus in treating female infertility. Improved systemic and ovarian immune functions, endometrial progesterone receptor and coreceptor expressions and uterine vascular adaptation to pregnancy were among features of enhanced progesterone-receptor sensitivity in the low-dose tacrolimus-treated mouse model of the disease. In this review, we have compiled available experimental and clinical data in literature on endometrial progesterone resistance and current therapeutic options, as well as mechanisms of actions and reported outcomes relevant to the potential therapeutic benefits for the use of low-dose tacrolimus in treating PCOS-associated female infertility.

Serum progesterone levels greater than 32.5 ng/ml on the day of embryo transfer are associated with lower live birth rate after artificial endometrial preparation: a prospective study

BACKGROUND

Previous observational studies have highlighted the negative effects of serum hormone levels at the minimum threshold during frozen embryo transfer (FET) cycles. However, still the questions regarding the maximum threshold level, and the highest allowed dosage of hormonal medications remain unresolved. The present study was conducted to determine whether there is any relationship between the serum progesterone and estradiol levels on the day of ET, and live birth rate (LBR) in patients receiving HRT in FET cycles.

METHODS

In this prospective cohort study, eligible women who were undergoing their first or second FET cycles with the top graded blastocyst stage embryos were included. All patients received the same HRT regimen. FET was scheduled 5 days after administration of the first dosage of progesterone. On the morning of ET, 4-6 h after the last dose of progesterone supplementation, the serum progesterone (P4, ng/ml) and estradiol (E2, pg/ml) levels were measured.

RESULTS

Amongst the 258 eligible women that were evaluated, the overall LBR was 34.1 % (88/258). The serum P4 and E2 values were divided into four quartiles. The means of women's age and BMI were similar between the four quartiles groups. Regarding both P4 and E2 values, it was found that the LBR was significantly lower in the highest quartile group (Q4) compared with the others, (P = 0.002 and P = 0.042, respectively). The analysis of the multivariable logistic regression showed that the serum level of P4 on ET day, was the only significant predictive variable for LBR. The ROC curve revealed a significant predictive value of serum P4 levels on the day of ET for LBR, with an AUC = 0.61 (95 % CI: 0.54-0.68, P = 0.002). The optimum level of serum P4, with 70 % sensitivity and 50 %specificity for LBR, was 32.5 ng/ml.

CONCLUSIONS

The present study suggests that a serum P4 value at the maximum threshold on the day of FET is associated with reduced LBR following blastocyst transfer. Therefore, measuring and monitoring of P4 levels during FET cycles might be necessary. However, the results regarding the necessity for the screening of serum E2 levels before ET, are still controversial, and further prospective studies are required.

Progesterone Regulates Glucose Metabolism Through Glucose Transporter 1 to Promote Endometrial Receptivity

Successful embryo implantation requires receptive endometrium, which is conducive to the process of embryo recognition, adhesion, and invasion within a certain period of time and is inseparable from the dynamic interaction between 17β-estradiol (E2) and progesterone (P4). Proper glucose metabolism is critical for the profound physiological changes in the endometrium entering the receptive state. And glucose transporters (GLUTs) are responsible for intracellular uptake of glucose and are the first step in glucose metabolism. Prior literature has reported the presence of GLUTs in the endometrium. However, we still do not understand the specific mechanisms of this process. In this study, we identified the effect of P4 on glucose transporter 1 (GLUT1) using in vivo animal models and determined the regulation of glucose metabolism by P4 in cells. We highly suspect that this pregnancy failure may be due to reduced GLUT1-mediated glucose metabolism, resulting in a decrease in endometrial receptivity caused by an inadequate energy supply and synthesis of substrate. Here, we propose a possible mechanism to explain how embryo implantation is affected by P4 and glucose utilization under abnormal endometrial conditions.

Serum progesterone level and ongoing pregnancy rate following frozen-thawed embryo transfer after artificial endometrial preparation: a monocentric retrospective study

INTRODUCTION

In some studies, early pregnancy loss (EPL) rate is higher with artificial cycle (AC) endometrial preparation for frozen-thawed embryo (FET) transfer than with other protocols, even though pregnancy rates are similar. An inadequate luteal phase support could explain these findings. The aim of this study was to compare, among the patients who had a pregnancy after FET with AC endometrial preparation, serum progesterone (PG) levels between those who experienced an EPL or an ongoing pregnancy.

MATERIAL AND METHODS

A monocentric retrospective cohort study, conducted at a University affiliated fertility center, studied 130 FET cycles with AC endometrial preparation between June 2016 and July 2017. Serum PG rates were compared according to reproductive outcomes and to endometrial preparation protocol on day 10 or 12 after FET (PG0) according to the embryo stage, and every 48h in case of pregnancy (i.e. PG1; PG2).

RESULTS

Among patients who had a pregnancy after FET with AC (n=33), serum PG levels were higher in case of an ongoing pregnancy than EPL, only significantly at PG1 (PG0 12.4ng/mL [7.5-14.6] vs 8.2ng/mL [6.0-13.0], p= 0.320; PG1 15.0 ng/mL [14.0-15.9] vs 8.5ng/mL [5.9-13.8], p= 0.048).

DISCUSSION

We found that serum PG level was lower in women experiencing early pregnancy loss after FET with AC endometrial preparation, potentially reflecting a lack of appropriate luteal phase support with PG. A cycle AC test, monitoring serum PG levels after its steady state, could detect this lack of PG, allowing physicians to adapt PG supplementation.

Measuring the serum progesterone level on the day of transfer can be an additional tool to maximize ongoing pregnancies in single euploid frozen blastocyst transfers

BACKGROUND

Endometrial preparation with hormone replacement therapy (HRT) is the preferred regimen for clinicians due to the opportunity to schedule the day of embryo transfer and for patients due to the requirement of fewer visits for frozen-warmed embryo transfers (FET). The increasing number of FETs raises the question of the serum P levels required to optimize the pregnancy outcome on the embryo transfer day.

METHODS

This prospective cohort study includes patients who underwent single euploid FET. All patients received HRT with oestradiol valerate (EV) and 100 mg of intramuscular (IM) progesterone (P). FET was scheduled 117-120 h after the first IM administration of 100 mg P. The serum P level was analyzed 1 h before the embryo transfer (ET). In all cycles, only embryos that were biopsied on day 5 were utilized for FET. Next generation sequencing (NGS) was used for comprehensive chromosomal analysis.

RESULTS

Overall, the ongoing pregnancy rate (OPR) was 58.9% (99/168). Data were then categorized according to the presence (Group I; n = 99) or the absence (Group II; n = 69) of an ongoing pregnancy. No significant differences regarding, female age, body mass index (BMI), number of previous miscarriages, number of previous live birth, sperm concentration, number of oocytes retrieved, number of mature oocytes (MII), rate of fertilized oocytes with two pronuclei (2PN), trophectoderm score, inner cell mass (ICM) score, endometrial thickness (mm), oestrodiol (E₂) and P levels prior to IM P administration were found between two groups. The P levels on the day of ET (ng/ml) were significantly higher in Group I (28 (5.6-76.4) vs 16.4 (7.4-60) p = 0.039). The P level on the day of ET was a predictor of a higher OPR (p < 0.001 OR: 1.033 95%CI [1.009-1.056]) after multivariate analysis. The ROC curve showed a significant predictive value of serum P levels on the day of ET for OPR, with an AUC (95%CI) = 0.716 (0.637-0.795). The optimal cut-off value for prediction of the OPR was a P level of 20.6 ng/ml (71.7% sensitivity, 56.5% specificity).

CONCLUSIONS

The present study suggests a minimum threshold of the serum P value on the day of ET that needs to be reached in HRT cycles to optimize the clinical outcome. Individualization of the P dosage should be evaluated in further studies.

Endometrial preparation for third-party parenting and cryopreserved embryo transfer

The advent of third party parenting ushered in the era of artificial stimulation of the endometrium. Initially intended only for patients with ovarian failure, exogenous induction of endometrial receptivity was quickly shown to be as good as natural endometrial preparation, with the advantage that the timing of embryo transfer could be controlled. It is perhaps surprising that even though the ovary produces a variety of steroids, that estradiol (E₂) and progesterone (P) alone would be needed to achieve optimal receptivity; no other substance has ever been shown to improve on the basic regimen of E₂ and P. A variety of routes of administration are available for both E₂ and P and physiologic (or supraphysiologic) serum or endometrial tissue levels of both can be achieved. The optimal duration of E₂ stimulation and the timing of the onset of P administration continue to be debated, but it appears that imitating the sequence that normally occurs in nature leads to optimal results. The poorly responsive endometrium and cases of recurrent implantation failure remain a challenge, but the clear majority of patients can successfully achieve pregnancy as long as embryos of adequate quality are transferred.

Endometrial compaction (decreased thickness) in response to progesterone results in optimal pregnancy outcome in frozen-thawed embryo transfers

OBJECTIVE

To evaluate whether the change in endometrial thickness between the end of the estrogen phase and the day of embryo transfer has an impact on the pregnancy rate in frozen-thawed embryo transfer (FET) cycles.

DESIGN

Retrospective observational cohort study.

SETTING

Single tertiary care medical center.

PATIENT(S)

Ultrasound images in 274 FET cycles were reviewed. All patients underwent endometrial preparation with the use of hormonal therapy.

INTERVENTIONS(S)

Ultrasound measurements of endometrial thickness at the end of the estrogen phase and the day of embryo transfer.

MAIN OUTCOME MEASURE(S)

The change in endometrial thickness and ongoing pregnancy rate.

RESULT(S)

We calculated the ongoing pregnancy rate in patients whose endometrial thickness decreased (compacted) after starting progesterone by 5%, 10%, 15%, or 20% compared with patients with no change or increased endometrial thickness. The ongoing pregnancy rate was significantly increased at all levels of compaction compared with no compaction. The ongoing pregnancy rate showed a significant increase with each decreasing quartile of change in thickness (increased percentage of compaction) in the progesterone phase compared with the estrogen phase.

CONCLUSION(S)

There is a highly significant inverse correlation between the ongoing pregnancy rate and the change of endometrial thickness between the end of estrogen administration and the day of embryo transfer.

Serum progesterone distribution in normal pregnancies compared to pregnancies complicated by threatened miscarriage from 5 to 13 weeks gestation: a prospective cohort study

Background

Progesterone is a critical hormone in early pregnancy. A low level of serum progesterone is associated with threatened miscarriage. We aim to establish the distribution of maternal serum progesterone in normal pregnancies compared to pregnancies complicated by threatened miscarriage from 5 to 13 weeks gestation.

Methods

This is a single centre, prospective cohort study of 929 patients. Women from the Normal Pregnancy [NP] cohort were recruited from antenatal clinics, and those in the Threatened Miscarriage [TM] cohort were recruited from emergency walk-in clinics. Women with multiple gestations, missed, incomplete or inevitable miscarriage were excluded from the study. Quantile regression was used to characterize serum progesterone levels in the NP and TM cohorts by estimating the 10th, 50th and 90th percentiles from 5 to 13 weeks gestation. Pregnancy outcome was determined at 16 weeks of gestation. Subgroup analysis within the TM group compared progesterone levels of women who subsequently miscarried with those who had ongoing pregnancies at 16 weeks of gestation.

Results

Median serum progesterone concentration demonstrated a linearly increasing trend from 57.5 nmol/L to 80.8 nmol/L from 5 to 13 weeks gestation in the NP cohort. In the TM cohort, median serum progesterone concentration increased from 41.7 nmol/L to 78.1 nmol/L. However, median progesterone levels were uniformly lower in the TM cohort by approximately 10 nmol/L at every gestation week. In the subgroup analysis, median serum progesterone concentration in women with ongoing pregnancy at 16 weeks gestation demonstrated a linearly increasing trend from 5 to 13 weeks gestation. There was a marginal and non-significant increase in serum progesterone from 19.0 to 30.3 nmol/L from 5 to 13 weeks gestation in women who eventually had a spontaneous miscarriage.

Conclusions

Serum progesterone concentration increased linearly with gestational age from 5 to 13 weeks in women with normal pregnancies. Women with spontaneous miscarriage showed a marginal and non-significant increase in serum progesterone. This study highlights the pivotal role of progesterone in supporting an early pregnancy, with lower serum progesterone associated with threatened miscarriage and a subsequent complete miscarriage at 16 weeks gestation.

Electronic supplementary material

The online version of this article (10.1186/s12884-018-2002-z) contains supplementary material, which is available to authorized users.

Effect of randomized serum progesterone concentration on secretory endometrial histologic development and gene expression

STUDY QUESTION

What doses of secretory phase progesterone (P) in women are associated with altered endometrial structure and/or function?

SUMMARY ANSWER

Consistently delayed histological maturation was seen at the lowest tested daily P dose (2.5 mg), whereas consistently altered functional response, as reflected by microarray analysis of gene expression was seen at both the 5 and 2.5 mg doses.

WHAT IS KNOWN ALREADY

Progesterone is absolutely required for normal embryo implantation and pregnancy survival. Progesterone supplementation is beneficial in ART cycles.

STUDY DESIGN, SIZE, DURATION

In this case-control experimental trial, 46 healthy young female volunteers (age 19-34) underwent a single modeled endometrial cycle after GnRH down-regulation or monitored in natural cycles.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In a university hospital, modeled cycles were obtained by GnRH agonist down-regulation, transdermal estradiol (E2) (0.2 mg/d), and daily injections of P in oil for 10 days: 2.5 mg (n = 6), 5 mg (n = 6), 10 mg (n = 12) or 40 mg (n = 12), after the 10th day of E2. Ten healthy, ovulatory women were used as controls. Endometrial biopsies were obtained on the 10th day of P exposure, or urinary LH surge (in controls). Analysis included histological dating, serum progesterone levels, microarray analysis of the whole genome, RT-PCR, western blot and comparison with the GEO database.

MAIN RESULTS AND THE ROLE OF CHANCE

In endometrial biopsies, a morphological delay appears in the 2.5 mg/day of P group. Higher sub-physiological levels of P (≥5 mg/day) resulted in normal histology, but aberrant gene expression. P levels required for consistent histological delay were lower than those in all ovulatory women. Gene expression abnormalities occurred at higher sub-physiological P concentrations, without a change in histology, a functional-morphological disassociation. The expression of some endometrial receptivity-associated genes appeared multiphasic, with peak or nadir of mean or median expression levels between the lowest and highest doses, suggesting sustained supraphysiological doses seen in ART treatment cycles may not be optimal.

LARGE SCALE DATA

GEO DataSets ID: 200056980; GSE 56980.

LIMITATIONS, REASONS FOR CAUTION

These results were obtained in fertile women, who may respond differently from infertile subjects.

WIDER IMPLICATIONS OF THE FINDINGS

The dose of P required for normal endometrial structure (5 mg/day) corresponds to a P concentration well below that seen in ovulatory women, suggesting that persistently delayed mid-secretory histology cannot be solely due to inadequate P concentrations in an ovulatory cycle. Endometrial gene expression is differentially regulated by different doses of progesterone. The apparent multiphasic response of some genes to P dose suggests the possibility that P concentration kinetics may play a role in normal endometrial preparation for receptivity. These findings strongly confirm that histologic development is not a reliable measure of endometrial P action.

STUDY FUNDING/COMPETING INTEREST(S)

Supported by The Eunice Kennedy Shriver National Institute for Child Health and Disease, National Institute of Health, USA (NICHD/NIH) (R01HD067721 and U54HD30476; SLY and BAL) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) 240239/2012-1 (RFS). All authors have no competing interests.

Menstrual Cycle Hormone Changes in Women Traversing Menopause: Study of Women's Health Across the Nation

CONTEXT

Menstrual cycle hormone patterns in women approaching menopause are inadequately studied.

OBJECTIVE

To describe day-to-day menstrual cycle hormones in women as they approach menopause from the Study of Women's Health Across the Nation Daily Hormone Study (DHS).

DESIGN

DHS enrollees collected daily urine for one entire menstrual cycle or up to 50 days, whichever came first, annually, up to the final menstrual period (FMP) or for up to 10 years.

SETTING

Seven sites across the United States.

PARTICIPANTS

A total of 511 premenopausal or early perimenopausal women at enrollment, within 10 years before menopause.

INTERVENTION

Time-to-FMP measurement.

MAIN OUTCOME MEASURES

Evidence of luteal activity (ELA), determined using objective algorithms. Menstrual cycle/segment length; whole cycle, and segment integrated urinary luteinizing hormone, follicle-stimulating hormone, estrone conjugates, and pregnanediol glucuronide (Pdg) for each year, organized around the FMP.

RESULTS

Mean menstrual cycle length was remarkably preserved at 26 to 27 days in ELA cycles; non-ELA cycles had greater variability. The percentage of cycles that were ELA remained high until 5 years before the FMP (87.9%); only 22.8% of cycles within 1 year of the FMP were ELA. Whole cycle hormones remained relatively stable up to 3 years before the FMP, when gonadotropins began to increase. Pdg excretion declined slowly with progress to the FMP, but Pdg patterns of ELA cycles remained distinguishable from non-ELA.

CONCLUSIONS

Menstrual cycle hormone patterns in perimenopausal women resemble those of midreproductive-aged women until 5 years before menopause, and presumably ovulatory cycles retain a potentially fertile pattern up to the end of reproductive life.

The role of progesterone therapy in early pregnancy: from physiological role to therapeutic utility

Progesterone is a steroid hormone of essential role in reproduction. In early pregnancy, it is responsible for preparation of endometrium for implantation process and maintenance of gestational sac in uterus, also by modulation of maternal immune system. Even though, several indices has been proposed as markers of endogenous progesterone synthesis (progesterone or luteinizing hormone measurements, endometrial biopsy), none has been proved to be reliable in detecting luteal phase defect. Currently, several pharmaceutical formulations are available, but in clinical setting the non-oral formulations seems to be effective in therapy. Progesterone is effective in the treatment of patients undergoing assisted reproductive technology procedure, as a luteal phase support. Some studies showed also its efficacy in the treatment of threatening or recurrent miscarriage, but newer trials neglected this beneficial effect. Due to controversies regarding utility of progesterone supplementation in these conditions, further studies are needed to address this issue.

Prospective evaluation of luteal phase length and natural fertility

OBJECTIVE

To evaluate the impact of a short luteal phase on fecundity.

DESIGN

Prospective time-to-pregnancy cohort study.

SETTING

Not applicable.

PATIENT(S)

Women trying to conceive, ages 30-44 years, without known infertility.

INTERVENTION(S)

Daily diaries, ovulation prediction testing, standardized pregnancy testing.

MAIN OUTCOME MEASURE(S)

Subsequent cycle fecundity.

RESULT(S)

Included in the analysis were 1,635 cycles from 284 women. A short luteal phase (≤11 days including the day of ovulation) occurred in 18% of observed cycles. Mean luteal phase length was 14 days. Significantly more women with a short luteal phase were smokers. After adjustment for age, women with a short luteal phase had 0.82 times the odds of pregnancy in the subsequent cycle immediately following the short luteal phase compared with women without a short luteal phase. Women with a short luteal length in the first observed cycle had significantly lower fertility after the first 6 months of pregnancy attempt, but at 12 months there was no significant difference in cumulative probability of pregnancy.

CONCLUSION(S)

Although an isolated cycle with a short luteal phase may negatively affect short-term fertility, incidence of infertility at 12 months was not significantly higher among these women.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01028365.

Combination therapeutic options in the treatment of the luteal phase deficiency

Luteal phase deficiency (LPD) is described as a condition of insufficient progesterone exposure to maintain a regular secretory endometrium and allow for normal embryo implantation and growth. There is evidence that both follicular and luteal phase abnormalities can result in LPD cycles. The aim of this randomized prospective noncomparative study is to evaluate the effectiveness of combination therapy in patients with LPD. This prospective study included 35 women of the reproductive age. They were diagnosed with the LPD with sonographically and laboratory-verified methods. The age of patients was 36 ± 0.46 years. The results of the study sonographically demonstrated an increase in the diameter of the corpus luteum from 1.36 ± 0.32 (initially) to 2.16 ± 0.21 mm after combination therapy. In addition, there was a statistically significant increase in the level of estrogens and progesterone in the corresponding phases of the menstrual cycle. Thus, the combination therapy for patients with LPD contributes to the recovery of cyclic events in the hypothalamic-pituitary-gonadal system, which determines the restoration of the endocrine function of the ovaries and promotes adequate secretory rearrangement of the endometrium in women of reproductive age.

Both slowly developing embryos and a variable pace of luteal endometrial progression may conspire to prevent normal birth in spite of a capable embryo

Embryonic implantation requires synchrony between the endometrium and the embryo. When analyzed in isolation, competent embryos may be unsuccessful when placed on a nonreceptive endometrium or vice versa, contributing to the "black box" of implantation failure. It is when the two are assessed together that dyssynchrony becomes evident, due to premature progesterone stimulus on the endometrium, physiologic displacement of the window of implantation or late blastulation of the embryo, or all combined. From the embryonic component, detailed assessment of the timing of blastulation is essential. The molecular diagnosis of endometrial receptivity based on its transcriptomic signature could be superior to other techniques used in the past for defining the endometrial window of implantation.

Evidence that exposure to progesterone alone is a sufficient stimulus to cause a precipitous rise in the immunomodulatory protein the progesterone induced blocking factor (PIBF)

PURPOSE

To determine if exposure to progesterone alone is sufficient to increase the production of the immunomodulatory protein known as the progesterone induced blocking factor (PIBF). Also to determine what method of progesterone delivery or form of P best stimulates PIBF secretion.

METHODS

Serum samples from patients with infertility and paid volunteers were evaluated for both PIBF and progesterone at various times during the follicular phase and the luteal phase in both natural cycles and cycles involving embryo transfer after endogenous and exogenous progesterone exposure and after various synthetic progestins. PIBF was measured by a non-commercial research ELISA assay. Comparisons were made of serum PIBF before and after exposure to progesterone, 17-hydroxyprogesterone, and oral contraceptives. PIBF was also measured before and after transfer of embryos.

RESULTS

Progesterone alone without exposure to the fetal allogeneic stimulus was able to produce a marked increase in serum PIBF. Neither a synthetic progestin (19-nortestosterone derivative) nor 17-hydroxyprogesterone caused an increase in PIBF. Some PIBF is generally detected even in the follicular phase.

CONCLUSIONS

A previous concept considered that an allogeneic stimulus, e.g., from the fetal semi-allograft, was necessary to induce de novo progesterone receptors in gamma delta T cells, which, in turn, when exposed to a high concentration of progesterone, would secrete high levels of PIBF. These data show that exposure to an allogeneic stimulus is not needed to cause a marked rise in PIBF, merely progesterone alone is sufficient.

Dietary factors and luteal phase deficiency in healthy eumenorrheic women

STUDY QUESTION

Are prospectively assessed dietary factors, including overall diet quality, macronutrients and micronutrients, associated with luteal phase deficiency (LPD) in healthy reproductive aged women with regular menstrual cycles?

SUMMARY ANSWER

Mediterranean Diet Score (MDS), fiber and isoflavone intake were positively associated with LPD while selenium was negatively associated with LPD after adjusting for age, percentage body fat and total energy intake.

WHAT IS KNOWN ALREADY

LPD may increase the risk of infertility and early miscarriage. Prior research has shown positive associations between LPD and low energy availability, either through high dietary restraint alone or in conjunction with high energy expenditure via exercise, but few studies with adequate sample sizes have been conducted investigating dietary factors and LPD among healthy, eumenorrheic women.

STUDY DESIGN, SIZE, DURATION

The BioCycle Study (2005-2007) prospectively enrolled 259 women from Western New York state, USA, and followed them for one (n = 9) or two (n = 250) menstrual cycles.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women aged 18-44 years, with self-reported BMI between 18 and 35 kg/m(2) and cycle lengths between 21 and 35 days, were included in the study. Participants completed baseline questionnaires, four 24-h dietary recalls per cycle and daily diaries capturing vigorous exercise, perceived stress and sleep; they also provided up to eight fasting serum samples during clinic visits timed to specific phases of the menstrual cycle using a fertility monitor. Cycles were included for this analysis if the peak serum luteal progesterone was >1 ng/ml and a urine or serum LH surge was detected. Associations between prospectively assessed diet quality, macronutrients and micronutrients and LPD (defined as luteal duration <10 days) were evaluated using generalized linear models adjusting for age, percentage body fat and total energy intake.

MAIN RESULTS AND THE ROLE OF CHANCE

LPD occurred in 41 (8.9%) of the 463 cycles from 246 women in the final analysis. After adjusting for age, percentage body fat and total energy intake, LPD was positively associated with MDS, adjusted odds ratio (aOR): 1.70 (95% confidence interval [CI]: 1.17, 2.48), P = 0.01. In separate macro- and micronutrient adjusted models, increased fiber and isoflavone intake showed modest positive associations with LPD: fiber (per g), aOR: 1.10 (95% CI: 0.99, 1.23), P = 0.07; and isoflavones (per 10 mg), aOR: 1.38 (95% CI: 0.99, 1.92), P = 0.06. In contrast, selenium (per 10 mcg) was inversely associated with LPD, aOR: 0.80 (95% CI: 0.65, 0.97), P = 0.03. Additional adjustments for relevant lifestyle factors including vigorous exercise, perceived stress and sleep did not appreciably alter estimates.

LIMITATIONS, REASONS FOR CAUTION

The number of LPD cycles was limited, and thus these findings are exploratory. We relied on participant self-report of their medical history to apply exclusion criteria; it is possible that we admitted to the study women with a gynecologic or medical disease who were unaware of their diagnosis.

WIDER IMPLICATIONS OF THE FINDINGS

Our study suggests that diet quality may be associated with LPD among healthy eumenorrheic women. As LPD may contribute to infertility and early miscarriage, further research is warranted to elucidate how dietary factors, such as MDS, may influence LPD. The inverse association we found with selenium is supported by previous research and deserves further investigation to determine whether this finding has pathophysiologic and therapeutic implications.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health. No competing interests declared.

Does progesterone supplementation improve pregnancy rates in clomiphene citrate and intrauterine insemination treatment cycles?

AIM

To investigate the effect of empiric use of luteal phase progesterone supplementation to improve endometrial receptivity in women undergoing treatment with clomiphene citrate in combination with intrauterine insemination (CC-IUI).

DESIGN

Retrospective cohort analysis.

SETTING

University fertility center.

PATIENTS

426 CC-IUI cycles from 292 patients with unexplained infertility.

INTERVENTIONS

Patients were treated with micronized intravaginal progesterone 100 mg twice daily beginning approximately three days after CC-IUI.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy per initiated cycle as defined by presence of fetal heart rate on ultrasound.

RESULTS

Clinical pregnancy rate was higher in patients receiving luteal phase support compared to patients not receiving luteal phase support (odds ratio: 2.04; 95% confidence interval: 1.01-4.14) after adjusting for all factors in the analysis using a multivariate logistic regression model. Age at the start of the cycle, BMI and CC dose were not shown to have an effect on clinical pregnancy rates. Patients with endometrial lining (EML) thickness 6-8 mm and >8 mm had increased clinical pregnancy rates compared to EML <6 mm independent of luteal phase progesterone use. Patients who appear to receive the greatest benefit of progesterone supplementation are in the 6-8 mm EML cohort.

CONCLUSIONS

Luteal phase progesterone supplementation in CC-IUI cycles can improve endometrial receptivity as judged by the improved clinical pregnancy rates as the primary outcome.

Progesterone and the luteal phase: a requisite to reproduction

Progesterone production from the corpus luteum is critical for natural reproduction. Progesterone supplementation seems to be an important aspect of any assisted reproductive technology treatment. Luteal phase deficiency in natural cycles is a plausible cause of infertility and pregnancy loss, though there is no adequate diagnostic test. This article describes the normal luteal phase of the menstrual cycle, investigates the controversy surrounding luteal phase deficiency, and presents the current literature for progesterone supplementation during assisted reproductive technologies.

Characterization of GAB1 expression over the menstrual cycle in women with and without polycystic ovarian syndrome provides a new insight into its pathophysiology

CONTEXT

In a previous microarray analysis, GRB2-associated binding protein 1 (GAB1), a docking protein closely related to the insulin receptor substrate, was down-regulated in endometrium of women with polycystic ovary syndrome (PCOS).

OBJECTIVE

The objective of the study was to characterize the cyclic expression of endometrial GAB1 in vivo in normal women and those with PCOS as well as investigate the possible mechanisms of endometrial regulation of GAB1 expression and action in vitro.

DESIGN

This was an experimental and case-control study.

SETTING

The study was conducted at a tertiary university hospital.

PATIENTS

Normal proven fertile women (controls; n = 31) and women with PCOS (cases; n = 26) participated in the study.

INTERVENTIONS

INTERVENTIONS included timed endometrial biopsies at different phases of the menstrual cycle. Ishikawa cells were cultured with β-estradiol (E2), medroxyprogesterone acetate, and E2 + medroxyprogesterone acetate. Transfection of small interfering RNA for GAB1 in Ishikawa cells incubated with or without insulin.

MAIN OUTCOME MEASURES

GAB1 mRNA expression in Ishikawa cells and in endometrium of cases and controls was measured. Protein expression of phosphorylated MAPK by Western blot was also measured. Immunohistochemical localization and expression of phosphorylated GAB1 in endometrium was also measured, using a digital histological score.

RESULTS

In endometrial tissue, GAB1 mRNA was reduced in the proliferative phase of PCOS women, compared with controls (P = .003; ANOVA). When all the phases of the menstrual cycle were grouped, GAB1 protein expression was reduced in endometrium of PCOS women (P < .0001; Student t test). E2 increases GAB1 mRNA expression in Ishikawa cells (P = .001; ANOVA). Phosphorylated MAPK is reduced in cells transfected with small interfering RNA for GAB1 (P = .008; ANOVA) and incubated with insulin.

CONCLUSIONS

GAB1 mRNA expression is positively modulated by E2. Endometrial GAB1 protein and mRNA expression are reduced in women with PCOS, suggesting that the endometrium of PCOS women have a defect in insulin signaling due to GAB1 down-regulation.

Luteal phase deficiency in regularly menstruating women: prevalence and overlap in identification based on clinical and biochemical diagnostic criteria

CONTEXT

Although adequate luteal hormone production is essential for establishing pregnancy, luteal phase deficiency (LPD) is poorly characterized among eumenorrheic women.

OBJECTIVE

We assessed the prevalence and overlap of two established LPD diagnostic criteria: short luteal phase duration less than10 days (clinical LPD) and suboptimal luteal progesterone of 5 ng/mL or less (biochemical LPD) and their relationship with reproductive hormone concentrations.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a prospective study in western New York (2005-2007) following 259 women, aged 18-44 years, for up to two menstrual cycles.

RESULTS

Among ovulatory cycles with recorded cycle lengths (n = 463), there were 41 cycles (8.9%) with clinical LPD, 39 cycles (8.4%) with biochemical LPD, and 20 cycles (4.3%) meeting both criteria. Recurrent clinical and biochemical LPD was observed in eight (3.4%) and five (2.1%) women, respectively. Clinical and biochemical LPD were each associated with lower follicular estradiol (both P ≤ .001) and luteal estradiol (P = .03 and P = .02, respectively) after adjusting for age, race, and percentage body fat. Clinical, but not biochemical, LPD was associated with lower LH and FSH across all phases of the cycle (P ≤ .001).

CONCLUSIONS

Clinical and biochemical LPD were evident among regularly menstruating women. Estradiol was lower in LPD cycles under either criterion, but LH and FSH were lower only in association with shortened luteal phase (ie, clinical LPD), indicating that clinical and biochemical LPD may reflect different underlying mechanisms. Identifying ovulation in combination with a well-timed luteal progesterone measurement may serve as a cost-effective and specific tool for LPD assessment by clinicians and researchers.

Potential influence of the microbiome on infertility and assisted reproductive technology

Although an altered vaginal microbiota has been demonstrated to affect parturition, its role in assisted reproductive technologies is uncertain. Nevertheless, the effect of known pathogens such as Mycoplasma tuberculosis, Chlamydia trachomatis, and Neisseria gonorrhoeae is clear, causing subclinical changes thought to be risk factors in subfertility. The Human Microbiome Project (HMP) has allowed for metagenomic studies to aid in characterizing normal vaginal flora. Recent findings from the HMP demonstrate that many different species of Lactobacillus are present in the vaginal tract, with a few that predominate. Studies that characterize the vaginal microbiome in assisted reproductive technology support the hypothesis that colonizing the transfer-catheter tip with Lactobacillus crispatus at the time of embryo transfer may increase the rates of implantation and live birth rate while decreasing the rate of infection. In addition, there is some evidence that a progesterone-resistant endometrium might increase the risk of an abnormal vaginal microbiome.

Subcutaneous progesterone versus vaginal progesterone gel for luteal phase support in in vitro fertilization: a noninferiority randomized controlled study

OBJECTIVE

To compare the safety, efficacy, and tolerability of subcutaneous progesterone (Prolutex, 25 mg; IBSA Institut Biochimique SA) with vaginal progesterone gel (Crinone, 8%; Merck Serono) for luteal phase support (LPS) in assisted reproduction technologies (ART) patients.

DESIGN

Prospective, open-label, randomized, controlled, parallel-group, multicenter, two-arm, noninferiority study.

SETTING

Thirteen European fertility clinics.

PATIENT(S)

A total of 683 ART patients randomized to two groups: Prolutex, 25 mg subcutaneously daily (n = 339); and Crinone, 90 mg 8% gel daily (n = 344).

INTERVENTION(S)

In vitro fertilization and embryo transfer were performed according to site-specific protocols. On the day of oocyte retrieval, Prolutex or Crinone gel was begun for LPS and continued for up to 10 weeks.

MAIN OUTCOME MEASURE(S)

Ongoing pregnancy rate.

RESULT(S)

The primary end point, ongoing pregnancy rates at 10 weeks of treatment were 27.4% and 30.5% in the Prolutex and Crinone groups, respectively (intention to treat [ITT]). The nonsignificant difference between the groups was -3.09% (95% confidence interval [CI] -9.91-3.73), indicating noninferiority of Prolutex to Crinone. Delivery and live birth rates resulted to be equivalent between the two treatments (26.8% vs. 29.9% in the Prolutex and Crinone groups, respectively [ITT]; difference -3.10 [95% CI -9.87-3.68]). No statistically significant differences were reported for any of the other secondary efficacy endpoints, including comfort of usage and overall satisfaction.

CONCLUSION(S)

Implantation rate, pregnancy rate, live birth rate, and early miscarriage rate for Prolutex were similar to those for Crinone. The adverse event profiles were similar and Prolutex was safe and well tolerated.

CLINICAL TRIAL REGISTRATION NUMBER

NCT00827983.

The role of progesterone and the progesterone receptor in human reproduction and cancer

Insufficient progesterone, effect possibly more on immune factors rather than adequate endometrial development, can be an easy remedial cause of infertility by simply supplementing the luteal phase with either vaginal or intramuscular or oral (dydrogesterone) progesterone. Progesterone will also help to reduce miscarriage rates when follicle maturing drugs are used for those with regular menses but follicular maturation defects, or women with recurrent miscarriages. One mechanism of action seems to be related to production of an immunomodulatory protein, the progesterone-induced blocking factor either in the cytoplasm or in the circulation. PIBF inhibits cytotoxicity of natural killer cells. Cancer cells may 'borrow' the same mechanism to escape NK cell immunosurveillance.