Endometrial thickness and IVF cycle outcomes: a meta-analysis

Walking on thin endometrium

PURPOSE OF REVIEW

Endometrial thickness has been regarded a predictor of success in assisted reproductive technology cycles and it seems a common practice to cancel embryo transfer when it is below a cut-off. However, various cut-offs have been proposed without a causal relationship between endometrial thickness and embryo implantation being established, casting doubt on the current dogma.

RECENT FINDINGS

Methodological limitations of the available studies on endometrial thickness are increasingly recognized and better designed studies do not demonstrate a cut-off value which requires cancelling an embryo transfer.

SUMMARY

Endometrium is important for implantation and a healthy pregnancy; however, ultrasound measured thickness does not seem to be a good marker of endometrial function.

A retrospective cohort study to examine factors affecting live birth after hysteroscopic treatment of intrauterine adhesions

OBJECTIVE

To evaluate independent factors that affect the chance of live birth (LB) after hysteroscopic adhesiolysis in patients with intrauterine adhesions.

DESIGN

Retrospective cohort study.

SETTING

Hysteroscopic center of Fuxing Hospital in Beijing, China.

PATIENT(S)

Patients diagnosed with Asherman syndrome between June 2020, and February 2022.

INTERVENTION(S)

Hysteroscopic adhesiolysis is followed by a second look hysteroscopy to assess the outcome and follow-up for a year.

MAIN OUTCOME MEASURE(S)

Live birth rate (LBR) without the use of assisted reproductive technologies at 12-month follow-up.

RESULT(S)

Of the 544 women included in the cohort, the pregnancy rate at the end of 1 year of follow-up was 47.6% (95% confidence interval [CI] 45.5%-49.7%), and the LBR was 41.0% (95% CI 38.9%-43.1%). Stepwise multiple logistic regression analysis identified three independent predictors of LB in decreasing order of significance: increase in menstrual flow after surgery (odds ratio [OR] 3.69, 95% CI 1.77-8.21), postoperative endometrial thickness in the midluteal phase (OR 1.53, 95% CI 1.31-1.80), and the severity of recurred adhesion at second-look hysteroscopy (OR 0.62, 95% CI 0.50-0.76). Among subjects with good independent prognostic factors, namely, increased menstrual flow after surgery, postoperative endometrial thickness in the midluteal phase >6 mm, and no or minimal recurrence of adhesions at second-look hysteroscopy, the LBR was 69.0% (95% CI 65.4%-72.6%). On the other hand, in women (n = 26) without any of the three good prognostic factors, none had a successful LB (0).

CONCLUSION(S)

Overall, the LBR after treatment for Asherman syndrome was 41.0%. The prognosis is dependent on three outcome measures after surgery, namely, improvement in menstrual flow, postoperative endometrial thickness, and the minimal degree of recurrent adhesions at second-look hysteroscopy.

Endometrium development patterns and BMI groups among in vitro fertilization patients; prognostic aspects

Introduction

The impact of the obesity pandemic on female reproductive capability is a factor that needs to be investigated. In addition, the link between endometrial thickness and in vitro fertilization (IVF) outcomes is contentious.

Goal

Our goal was to analyze the association among endometrium development, hormone levels, embryo quality, clinical pregnancy, anamnestic parameters, and body mass index (BMI) in women receiving IVF treatment.

Patients and methods

537 participants undergoing IVF/ICSI cycles with successful oocyte retrieval were enrolled. Subjects were divided into four BMI based groups: underweight (UW; n=32), normal weight (NW; n=324), overweight (OW; n= 115), obesity (OB; n=66). Anthropometric and anamnestic parameters, characteristics of stimulation, endometrial thickness on the day of hCG injection, at puncture, at embryo transfer, FSH, LH, AMH, partner's age and the semen analysis indicators, embryo quality, clinical pregnancy, were recorded and analyzed. Support Vector Machine (SVM) was built to predict potential pregnancies based on medical data using 22 dimensions.

Results

In accordance with BMI categories, when examining pregnant/non-pregnant division, the average age of pregnant women was significantly lower in the UW (30.9 ± 4.48 vs. 35.3 ± 5.49 years, p=0.022), NW (34.2 ± 4.25 vs. 36.3 ± 4.84 years, p<0.001), and OW (33.8 ± 4.89 vs. 36.3 ± 5.31 years, p=0.009) groups. Considering FSH, LH, and AMH levels in each BMI category, a statistically significant difference was observed only in the NW category FSH was significantly lower (7.8 ± 2.99 vs. 8.6 ± 3.50 IU/L, p=0.032) and AMH (2.87 ± 2.40 vs. 2.28 ± 2.01 pmol/L, p=0.021) was higher in pregnant women. There were no further statistically significant differences observed between the pregnant and non-pregnant groups across any BMI categories, especially concerning endometrial development. Surprisingly, BMI and weight correlated negatively with FSH (r=-0.252, p<0.001; r=-0.206, p<0.001, respectively) and LH (r= -0.213, p<0.001; r= -0.195, p<0.001) in the whole population. SVM model average accuracy on predictions was 61.71%.

Discussion

A convincing correlation between endometrial thickness development and patients' BMI could not be substantiated. However, FSH and LH levels exhibited a surprising decreasing trend with increasing BMI, supporting the evolutionary selective role of nutritional status. Our SVM model outperforms previous models; however, to confidently predict the outcome of embryo transfer, further optimization is necessary.

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).

Increasing Endometrial Thickness Beyond 8 mm Does Not Alter Clinical Pregnancy Rate After Single Euploid Embryo Transfer

The aim of this study was to investigate if variation in endometrial thickness affects clinical pregnancy and live birth rates among patients undergoing single euploid embryo transfer (SET). A retrospective review of IVF cycles performed at a single private fertility institution between 2015 and 2020 was performed. Patients with normal uterine anatomy undergoing their first SET of a euploid embryo undergoing their first cycle at the center were included, for a total of 796 cycles. Endometrial thickness was measured by transvaginal ultrasound following 10-14 days of estradiol exposure. Specific infertility diagnoses did not significantly impact endometrial lining thickness with means across diagnoses ranging from 9.3 to 11.0 mm. Endometrial thickness was grouped into five categories: < 8 mm, 8-10 mm, 10-13 mm, 13-15 mm, and ≥ 15 mm. Using 8-10 mm as the reference group, the odds ratio of live birth was 0.5, 1.22, 1.05, and 1.05 for < 8 mm, 10-13 mm, 13-15 mm, and ≥ 15 mm groups, respectively. Risk of first trimester miscarriage was equivalent across groups. There was a trend toward an increased rate of biochemical pregnancies in patients with a < 8 mm and ≥ 15 mm endometrium; however, this was not statistically significant. The clinical pregnancy and live birth rate were lowest in patients with < 8-mm endometrial thickness. For single euploid embryo transfers, an endometrial lining greater than or equal to 8 mm confers optimal live birth rates following a medicated FET cycle. These data confirm the findings of prior studies in fresh embryo transfers without the confounders of supraphysiologic ovarian hormone concentrations and genetically untested embryos.

Progress on the Endometrium

The endometrium is a dynamic tissue that facilitates mammalian internal reproduction and thus, the ability to deliver live born progeny that are more easily protected from predators. This tissue is unique in its ability to undergo cyclic regeneration and destruction in the absence of pregnancy. Ovarian steroids guide endometrial proliferation and maturation promoting its receptivity and selectivity with regards to blastocyst implantation. It is decidualization, terminal stromal maturation, that prevents the trophoblast from breeching containment of the uterus and allows for endometrial sloughing should pregnancy not occur. Endometrial pathology is highly variable and therefore a wide array of diagnostic measures are required for its interrogation. There remains no single test that can distinguish between all potential issues and it is critical that appropriate and evidence-based endometrial assessment is carried out. Emerging data on developmental markers, inflammatory mediators, and bacterial profiling offer hope that conditions including endometriosis, cancer, infertility, and implantation failure will be more easily and less invasively diagnosed. This will allow for a more timely and targeted approach to intervention. Accordingly, assessing novel measures requires an evidence-based approach prior to their mass utilization.

Does endometrial compaction before embryo transfer affect pregnancy outcomes? a systematic review and meta-analysis

Objective

There is no clear evidence of clinical significance of endometrial compaction, which can be measured by a reduction in endometrial thickness (EMT) during the follicular-luteal transition before the day of embryo transfer. In this study, we aim to determine whether endometrial compaction has an effect on in vitro fertilization (IVF) success.

Methods

We searched PubMed, Cochrane, Embase, and Web of Science electronic databases for studies published in English up to March 2023. Heterogeneity between studies was assessed using the I2 statistic. The random effects model and fixed effects model was used to pool the risk ratio (RR) with a corresponding 95% confidence interval (CI). A subgroup analysis was performed based on different methods of ultrasonic measurement and different endometrial compaction rates (ECR). Stata 17.0 software was used for meta-analysis. Pregnancy outcomes, which included clinical pregnancy rate, ongoing pregnancy rate, live birth rate, and spontaneous abortion rate, were evaluated.

Results

In this study, 18 cohort studies were included, involving 16,164 embryo transfer cycles. Pooled results indicated that there was no significant difference between the endometrial compaction group and the non-compaction group in terms of clinical pregnancy rate (RR [95% CI]=0.98 [0.90,1.08]; I2 = 69.76%), ongoing pregnancy rate (RR [95% CI]=1.18 [0.95,1.47]; I2 = 78.77%), live birth rate (RR [95% CI]= 0.97 [0.92,1.02]; I2 = 0.00%) or spontaneous abortion rate (RR [95% CI]= 1.07[0.97,1.26]; I2 = 0.00%). According to the subgroup analysis of ultrasonic measurement methods, in the transvaginal ultrasound (TVUS) combined with abdominal ultrasonography (AUS) cycles of the endometrial compaction group, the rate of ongoing pregnancy (RR [95% CI] = 1.69 [1.26, 2.26]; I2 = 29.27%) and live birth (RR [95% CI] = 1.27 [1.00,1.61]; I2 = 62.28%) was significantly higher than that of the non-compaction group. Additionally, subgroup analysis based on ECR revealed a significantly higher rate of ongoing pregnancy when ECR ≥ 15% (RR [95% CI] = 1.99 [1.61, 2.47]; I2 = 0.00%).

Conclusion

Endometrial compaction has no adverse effect on clinical pregnancy rate, ongoing pregnancy rate, live birth rate, or spontaneous abortion rate. A possible explanation for the contradictory findings of previous studies lies in the method by which the EMT is measured.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023430511, identifier CRD42023430511.

Impact of endometrial compaction on reproductive outcomes after cryotransfer of euploid embryos in a modified natural cycle: protocol for a prospective cohort study

Introduction

Embryo implantation is a complex and poorly understood process. Most studies to date have focused on the analysis of the endometrium at the end of the estrogenic phase, while the available data on its importance after secretory transformation are limited and inconsistent. Current evidence does not allow for a conclusive interpretation of the changes observed in the pre-implantation endometrium, whether in the natural or replacement cycle, and their relevance in the development of a pregnancy or the implications for clinical practice.

Methods

Multicenter prospective observational cohort study. Based on our sample size calculation, the study group will consist of 206 women (exposed or "compaction" group: 103 women with a decrease of ≥ 5% in endometrial thickness between the estrogenic phase and the day of embryo transfer; non-exposed "non-compaction" group: 103 women with similar or greater endometrial thickness between these time points). The main objective of this study is to compare the ongoing pregnancy rates in natural cycles for euploid embryo transfer in patients who present endometrial compaction at the time of transfer versus those who with a stable or greater endometrial thickness with respect to the estrogenic phase. The estimated duration of the study is 30 months. Inclusion criteria are: 18 to 50 years of age, with primary or secondary infertility, subjected to endometrial preparation in a modified natural cycle for transfer of a genetically euploid blastocyst, from their own oocyte or oocyte donation, with a normal uterine cavity. Exclusion criteria are: uterine or endometrial disease (e.g., multiple myomatosis, severe adenomyosis, Asherman syndrome, refractory endometrium), conditions that prevent correct ultrasound assessment (tilted uterus), or a history of recurrent implantation failure or repeated miscarriages.

Discussion

The findings from this study will provide valuable insights into the potential influence of the "endometrial compaction" phenomenon on reproductive outcomes during natural cycle endometrial preparation. By examining this aspect, we aim to contribute to a better understanding of the factors that may impact successful outcomes in fertility treatments.

Establishment of a prediction model for the impact of endometrial thickness on the day of embryo transfer on ectopic pregnancy in frozen-thawed embryo transfer cycle

Objective

This study aims to investigate the factors affecting the ectopic pregnancy (EP) rate in the frozen-thawed embryo transfer (FET) cycle.

Methods

This study retrospectively analyzed 5606 FET cycles, including 5496 cycles resulting in intrauterine pregnancy and 110 cycles resulting in EP. Smooth curve fitting and piece-wise linear regression were utilized to evaluate a non-linear association between endometrial thickness (EMT) and EP. Multiple logistic regression analysis was used to study the effect of EMT on the embryo transfer (ET) day and other indexes on EP rate after adjusting for confounding factors. A nomographic prediction model was employed to predict EP occurrence. The predictive efficacy of the model was assessed using the area under the receiver operating characteristic (ROC) curve (AUC), utilizing the bootstrap sampling method for internal validation.

Results

After accounting for the confounding factors, the segmented linear regression analysis indicated that the EMT inflection point was 9 mm; the EP rate significantly decreased by 28% with each additional millimeter of EMT up to 9 mm (odds ratio (OR) = 0.72; 95% confidence interval (CI), 0.53-0.99; P = 0.0412) while insignificantly decreased when the EMT was greater than 9 mm (OR = 0.91; 95% CI, 0.76-1.08; P = 0.2487). Multivariate logistic regression analysis revealed that after adjusting for confounders, EP risk significantly increased in the number of previous EPs ≥ 1 (OR = 2.29; 95% CI, 1.26-4.16; P = 0.0064) and tubal factor infertility (OR = 3.86; 95% CI, 2.06-7.24; P < 0.0001). Conversely, EP risk was significantly reduced by the increased EMT (OR = 0.84; 95% CI, 0.74-0.96; P = 0.0078) and the blastocyst transfer (OR = 0.45; 95% CI, 0.27-0.76; P = 0.0027). These variables were used as independent variables in a nomogram prediction model, resulting in an AUC of 0.685. The nomination models were internally verified using self-sampling (bootstrap sampling resampling times = 500). This validation yielded an AUC of 0.689, with a sensitivity of 0.6915 and a specificity of 0.5790. The internal validation indicated minimal fluctuations in the AUC, signifying a relatively stable model.

Conclusion

Undergoing EMT on the day of ET poses a separate EP risk in the FET cycle; to mitigate the EP incidence, the EMT should exceed 9 mm before ET. Furthermore, previous EPs and tubal factor infertility were additional factors independently increasing EP risk. Furthermore, implementing blastocyst transfer demonstrated that EP incidence was significantly reduced. Utilizing a nomogram predicting system enables EP risk evaluation before ET for individual patients, establishing a basis for devising clinical strategies for ET.

Current perspectives on endometrial receptivity: A comprehensive overview of etiology and treatment

Recurrent implantation failure (RIF) remains a challenging problem in assisted reproductive technology (ART). Further insights into uterine abnormalities that can disturb embryo implantation should be obtained. This review provides an overview of the effects of organic and non-organic uterine disorders on endometrial receptivity. The results suggest that various uterine pathologies can lead to defective embryo implantation via multiple mechanisms. In particular, uterine adenomyosis dysregulates molecular and cellular interactions that are vital for successful embryo implantation with a background of chronic inflammation, which may be alleviated by pretreatment with a gonadotropin-releasing hormone agonist. Uterine myomas can cause endometrial deformation and adverse alterations in uterine contractility. Nonetheless, the effectiveness of myomectomy remains debated, and endometrial polyp removal may be considered, particularly in patients with RIF. Chronic endometritis abrogates the appropriate uterine immunological environment critical for embryo implantation. Abnormal endometrial microbiota have been suggested to influence endometrial receptivity; however, supporting evidence is currently scarce. Platelet-rich plasma therapy may be a potential treatment for thin endometria; nevertheless, further validation is required. Endometrial receptivity analysis can detect dysregulation of the window of implantation, and new non-invasive methods for predicting endometrial receptivity have recently been proposed. However, numerous issues still need to be fully clarified. Further clinical and basic studies are necessary to investigate the pathophysiology of defective endometrial receptivity and identify optimal treatments for patients undergoing ART, especially those with RIF.

A critical appraisal of studies on endometrial thickness and embryo transfer outcome

A receptive endometrium is required for successful embryo implantation. Endometrial thickness, as measured by ultrasonography, is the most commonly used marker of endometrial receptivity in assisted reproductive technology cycles. Several factors simultaneously affect both endometrial thickness and probability of live birth, including age, oestradiol concentration and oocyte number, among others. Most of the studies investigating a relationship between endometrial thickness and embryo transfer outcomes are retrospective and do not adequately address confounding factors, in addition to other limitations. Despite multiple meta-analyses and studies with large numbers of cycles, controversy still exists. The difference between the results from prospective and retrospective studies is also striking. This article presents a critical appraisal of the studies on endometrial thickness and embryo transfer outcomes in order to highlight methodological issues and how they can be overcome in future studies. Currently available evidence does not seem to support a modification of management just because endometrial thickness is below an arbitrary threshold.

Large-scale retrospective analysis of methodological factors affecting pregnancy rates after embryo transfer for in vitro fertilization

This study aimed to investigate the impact of methodological factors on pregnancy rates after embryo transfer (ET) for in vitro fertilization. This retrospective cross-sectional study was conducted between September 2020 and April 2022. A total of 2048 patients who underwent ultrasonography-guided first frozen embryo transfer (FET) or a fresh ET cycle due to infertility were included in the study. The effects of age, ET protocol (frozen or fresh), preimplantation genetic testing, number of embryos transferred (NET), and embryo fundus distance on pregnancy rate were investigated. The mean age of pregnant patients (31.51 ± 5.28) was significantly lower than that of non-pregnant patients (35.34 ± 6.39) (P < .001). Multiple regression analysis showed that women with lower age (P < .001), higher NET (P < .001), higher embryo fundus distance (P < .001), FET (P < .001), and preimplantation genetic testing (P = .012) had a significantly higher likelihood of pregnancy. Appropriate transfer depth, younger age, euploid embryo transfer, FET, and a higher NET can increase the likelihood of pregnancy. However, multiple factors must be considered when deciding the best protocol for a particular patient, including patient preference, costs and timing.

Hyperbaric oxygen therapy: a possible choice for patients with resistant thin endometrium during frozen embryo transfer treatments

BACKGROUND

Thin endometrium is considered suboptimal for embryo implantation, leading to compromised pregnancy rates without effective therapies. While some studies have reported promoted endometrial growth after a period of hyperbaric oxygen therapy (HBOT) in patients with intrauterine adhesion, there have been no reports in patients with resistant thin endometrium. The purpose of this study was to investigate the impact of HBOT on endometrium growth and pregnancy outcomes in patients with resistant thin endometrium during frozen embryo transfer (FET) treatments.

METHODS

This prospective pre-post cohort study was conducted at a university-affiliated assisted reproductive medical center between October 2021 and December 2022. Patients who had experienced at least one canceled transfer cycle due to a thin endometrium(< 7 mm) on the endometrium transformation day, despite the use of standard therapies as well as adjuvant therapies, were enrolled in the study. Patients were assigned voluntarily to either the HBOT group or the concurrent control group. The HBOT group received daily HBOT for at least 10 days during the proliferative phase, in addition to the routine endometrium preparation methods and the concurrent control group underwent cycles without HBOT. Propensity score matching (PSM) was used to ensure comparability between the groups. Both self-control and case-control comparisons were conducted. The primary outcome measured was endometrial thickness (ET) on the day of endometrium transformation. Secondary outcomes included intrauterine pregnancy rate (IPR), embryo implantation rate (IR), miscarriage rate, and others.

RESULTS

Patients in the HBOT group demonstrated a significantly thicker endometrial thickness on the day of endometrium transformation after undergoing therapy (5.76 ± 1.66 vs. 6.57 ± 1.23, P = 0.002). This improvement was accompanied by a decreased rate of cycle cancellations. Baseline parameters and endometrial thickness were comparable between the HBOT group and the concurrent control group during the cycle. The IPR was similar in patients who received cleavage-stage embryos (0.0% vs. 6.7%, P = 1.00), but significantly higher in patients in the HBOT group who received blastocysts (53.8% vs. 18.2%, P = 0.017).

CONCLUSIONS

A period of HBOT prior to endometrium transformation contributes to increased endometrial thickness and facilitates blastocyst implantation in patients with resistant thin endometrium during FET treatments.

TRIAL REGISTRATION

The trial was registered on the Chinese Clinical Trial Registry (registration no. ChiCTR2300072831, retrospectively registered).

Endometrial thickness and early pregnancy complications after frozen-thawed embryo transfers

Background

The relationship between endometrial thickness and pregnancy safety after in vitro fertilization treatment is an important topic that should provoke attention. The aim of this study was to demonstrate the relationship between endometrial thickness on day of embryo transfer and early pregnancy complications, including ectopic pregnancy and early miscarriage, in frozen thawed embryo transfer (FET) cycles.

Methods

Patients undergoing their first FET cycles were included into this study from January 2010 to December 2021. Patients were divided into three groups according to endometrial thickness on day of embryo transfer: Thin, ≤ 7 mm; Medium, 7-14 mm; Thick, ≥ 14 mm. Ectopic pregnancy and early miscarriage were the two primary outcomes. Endometrial thickness was the main measured variable. The risk factors of these two compilations were determined based on univariate analysis and multivariate logistic regression analysis.

Results

A total of 11138 clinical pregnancies were included. The overall ectopic pregnancy and early spontaneous miscarriage rates were 2.62% and 13.40%. The ectopic pregnancy and early spontaneous miscarriage rates were significantly higher in patients with thin endometrium as compared with those in the other two groups (ectopic pregnancy rate: 5.06% vs. 2.62% vs. 1.05%; P < 0.001; early spontaneous miscarriage rate: 15.18% vs. 13.45% vs. 11.53%; P < 0.001). In multivariate logistic regression analysis, thin endometrium was an independent factor to predict ectopic pregnancy [adjusted odds ratio (aOR): 5.62; 95% confidence interval (CI): 2.51-12.58, P < 0.001], and to predict early spontaneous miscarriage rate (aOR: 1.57; 95% CI: 1.21-1.74, P < 0.001).

Conclusion

Thin endometrium on day of embryo transfer in FET cycles is an independent predictor for early pregnancy compilations, including ectopic pregnancy and early spontaneous miscarriage.

Suitable endometrial thickness on embryo transfer day may reduce ectopic pregnancy rate and improve clinical pregnancy rate

BACKGROUND

This retrospective study aimed to investigate the most suitable endometrial thickness (EMT) on the day of embryo transfer that could reduce ectopic pregnancy rate (EPR) and improve clinical pregnancy rate (CPR) in fresh embryo transfer patients with early follicular phase long-acting regimen.

METHODS

A total of 11,738 IVF/ICSI cycles, comprising 4,489 non-clinical pregnancies, 7,121 intrauterine pregnancies, and 128 ectopic pregnancy cycles after fresh embryo transfer, recorded between September 2017 and December 2020. Clinical pregnancy (CP) and ectopic pregnancy (EP) were the primary outcomes. Multivariate logistic regression was used to calculate the adjusted odds ratio (aOR) and 95% confidence interval (CI) for EP and CP. Patients were divided into three groups based on the EMT (6-10 mm, 11-15 mm, and 16-20 mm). CPR and EPR per millimeter of EMT were drawn into a line chart, and three groups were analyzed by Chi-square test.

RESULTS

After controlling for potential confounders, EMT had a significant effect on CP (aOR = 1.07; 95% CI, 1.05-1.08; P = 0.00) and EP (aOR = 0.88; 95% CI, 0.82-0.94; P = 0.00). With the increase of EMT, CPR increased and EPR decreased. Pearson correlation coefficients were r = 0.708 (P = 0.00) and r =-0.558 (P = 0.03), respectively. Significant differenceswere detected in the CPRs and EPRs (all P = 0.00). The CPR in the 6-10 mm group (54.88%) was significantly lower than that in the 11-15 mm group (64.23%) and the 16-20 mm group (64.40%) (P = 0.00). The EPR in the 6-10 mm group (2.72%) was significantly higher than that in the other two groups (1.60% and 0.97%, P = 0.00). The difference in CPR and EPR between the 11-15 mm group and the 16-20 mm group was not statistically significant, which indicated that EMT ≥ 11 mm simultaneously reduced the EPR and increased the CPR.

CONCLUSIONS

EMT was inversely proportional to EPR and directly proportional to CPR in fresh embryo transfer cycles. The EMT ≥ 11 mm on the day of embryo transfer could simultaneously achieve lower EPR and higher CPR. Accordingly, more attention should be given to the EMT of women who underwent ART treatment.

Effect of the endometrial thickness on the live birth rate: insights from 959 single euploid frozen embryo transfers without a cutoff for thickness

OBJECTIVE

To investigate whether endometrial thickness (ET) independently affects the live birth rate (LBR) after embryo transfer.

DESIGN

Retrospective study.

SETTING

Private assisted reproductive technology center.

PATIENT(S)

A total of 959 single euploid frozen embryo transfers.

INTERVENTION(S)

Vitrified euploid blastocyst transfer.

MAIN OUTCOME MEASURE(S)

Live birth rate per embryo transfer.

RESULT(S)

The conditional density plots did not demonstrate either a linear relationship between the ET and LBR or a threshold below which the LBR decreased perceivably. Receiver operating characteristic curve analyses did not suggest a predictive value of the ET for the LBR. The area under the curve values were 0.55, 0.54, and 0.54 in the overall, programmed, and natural cycle transfers, respectively. Logistic regression analyses with age, embryo quality, day of trophectoderm biopsy, body mass index, and ET did not suggest an independent effect of the ET on the LBR.

CONCLUSION(S)

We did not identify a threshold of the ET that either precluded live birth or under which the LBR decreases perceivably. Common practice of cancelling embryo transfers when the ET is <7 mm may not be justified. Prospective studies, in which the management of the transfer cycle would not be altered by ET, would provide higher-quality evidence on the subject.

Effect of endometrial thickness on obstetric and neonatal outcomes in assisted reproduction: a systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis aimed to explore the relationship of endometrial thickness (EMT) with obstetric and neonatal outcomes in assisted reproductive cycles.

METHODS

PubMed, EMBASE, Cochrane Library and Web of Science were searched for eligible studies through April 2023. Obstetric outcomes include placenta previa, placental abruption, hypertensive disorders of pregnancy (HDP), gestational diabetes mellitus (GDM) and cesarean section (CS). Neonatal outcomes include birthweight, low birth weight (LBW), gestational age (GA), preterm birth (PTB), small for gestational age (SGA) and large for gestational age (LGA). The effect size was estimated as odds ratio (OR) or mean difference (MD) with 95% confidence interval (CI) using a random-effects model. Inter-study heterogeneity was assessed by the chi-square homogeneity test. One-study removal method was used to determine the sensitivity of the meta-analysis.

RESULTS

Nineteen studies involving 76,404 cycles were included. The pooled results revealed significant differences between the thin endometrium group and the normal group in placental abruption (OR = 2.45, 95% CI: 1.11-5.38, P = 0.03; I² = 0%), HDP (OR = 1.72, 95% CI: 1.44-2.05, P < 0.0001; I² = 0%), CS (OR = 1.33, 95% CI: 1.06-1.67, P = 0.01; I² = 77%), GA (MD = -1.27 day, 95% CI: -2.41- -1.02, P = 0.03; I² = 73%), PTB (OR = 1.56, 95% CI: 1.34-1.81, P < 0.0001; I² = 33%), birthweight (MD = -78.88 g, 95% CI: -115.79- -41.98, P < 0.0001; I² = 48%), LBW (OR = 1.84, 95% CI: 1.52-2.22, P < 0.00001; I² = 3%) and SGA (OR = 1.41, 95% CI: 1.17-1.70, P = 0.0003; I² = 15%). No statistical differences were found in placenta previa, GDM, and LGA.

CONCLUSION

Thin endometrium was associated with lower birthweight or GA and higher risks of placental abruption, HDP, CS, PTB, LBW and SGA. Therefore, these pregnancies need special attention and close follow-up by obstetricians. Due to the limited number of included studies, further studies are needed to confirm the results.

The impact of anti-Müllerian hormone on endometrial thickness in gonadotropin stimulation/intrauterine insemination cycles: is there an effect on pregnancy outcomes?

PURPOSE

To study the association, if any, between anti-Müllerian hormone (AMH) and pre-ovulatory endometrial thickness (ET) in gonadotropin/intrauterine insemination (IUI) cycles.

METHODS

This retrospective cohort study included a total of 964 patients undergoing 1926 gonadotropin/IUI cycles at an academic fertility center. Primary outcome measure was the association between serum AMH and measured ET on the day of and the day before human chorionic gonadotropin hormone (hCG) ovulation trigger. The effect of a model combining AMH and ET on early pregnancy outcomes was a secondary measure.

RESULTS

In 52.8% of cycles, ET was last assessed and recorded on the day of hCG administration, while in the remaining 47.2% on the day prior to trigger. In unadjusted regression models, AMH was weakly correlated with ET on hCG trigger day [bAMH (95%CI) = 0.032 (- 0.008, 0.070), p = 0.015]. When adjusting for potential confounders, the positive correlation became significant [0.051 (0.006, 0.102), p = 0.047]. Similar findings were observed when assessing the correlation between AMH and ET on the day prior to hCG trigger. ET was non-significantly associated with the odds of clinical pregnancy, when adjusting for potential confounders, except for when restricting the analysis to couples with idiopathic infertility [OR (95%CI), p-value: 0.787 (0.623, 0.993), 0.044].

CONCLUSION

Our findings support an effect of serum AMH on endometrial development in gonadotropin induced cycles, even when adjusting for the diagnosis of PCOS. ET was not associated with the odds of achieving a clinical pregnancy, except for couples with idiopathic infertility.

Clinical pregnancy outcomes prediction in vitro fertilization women based on random forest prediction model: A nested case-control study

The present study aimed to analyze the risk factors influencing the in vitro fertilization embryo transfer (IVF-ET) pregnancy and to construct a prediction model for clinical pregnancy outcome in patients receiving IVF-ET based on the predictors. In this nested case-control study, the data of 369 women receiving IVF-ET were enrolled. Univariate and multivariate Logistic regression analyses were conducted to identify the potential predictors. Ten-fold cross validation method was used to validate the random forest model for predicting the clinical pregnancy. The receiver operating characteristic curve was drawn to evaluate the prediction ability of the model. The importance of variables was shown according to Mean Decrease Gini. The data delineated that age (odds ratio [OR]= 1.093, 95% confidence interval [CI]: 1.036-1.156, P = .0010), body mass index (BMI) (OR = 1.094, 95%CI: 1.021-1.176, P = .012), 3 cycles (OR = 0.144, 95%CI: 0.028-0.534, P = .008), hematocrit (HCT) (OR = 0.865, 95% CI: 0.791-0.943, P = .001), luteinizing hormone (LH) (OR = 0.678, 95%CI: 0.549-0.823, P < .001), progesterone (P) (OR = 2.126, 95%CI: 1.112-4.141, P = .024), endometrial thickness (OR = 0.132, 95%CI: 0.034-0.496, P = .003) and FSH (OR = 1.151, 95%CI: 1.043-1.275, P = .006) were predictors associated with the clinical pregnancy outcome of patients receiving IVF-ET. The results might provide a novel method to identify patients receiving IVF-ET with a high risk of poor pregnancy outcomes and provide interventions in those patients to prevent the occurrence of poor pregnancy outcomes.

Thin endometrial lining: is it more prevalent in patients utilizing preimplantation genetic testing for monogenic disease (PGT-M) and related to prior hormonal contraceptive use?

STUDY QUESTION

Is a thin endometrial lining before ovulation triggering more prevalent in patients utilizing preimplantation genetic testing for monogenic disease (PGT-M) compared to the regular IVF/ICSI population and is this associated with prior hormonal contraceptive use?

SUMMARY ANSWER

Thin (<8 mm) endometrial lining is more prevalent in PGT-M patients compared to the regular IVF/ICSI population and is associated with both longer prior hormonal contraceptive use and a shorter cessation interval of hormonal contraceptives before IVF/ICSI treatment.

WHAT IS KNOWN ALREADY

Thin endometrial lining has been associated with lower pregnancy rates in IVF/ICSI cycles and increased chances of miscarriage and low birth weight. Endometrial thinning and atrophy occur during hormonal contraceptive use. Patients utilizing PGT-M typically use hormonal contraceptives up until treatment to avoid the risk of conception of a genetically affected child. Whether this could negatively affect endometrial thickness achieved during subsequent IVF/ICSI cycles is not known.

STUDY DESIGN, SIZE, DURATION

A retrospective case control study was performed, including all PGT-M patients attending the University Medical Centre Groningen (cases), between 2009 and 2018. The control group consisted of two non-PGT IVF/ICSI patients for each PGT-M patient, matched for age and treatment period.

PARTICIPANTS/MATERIALS, SETTING, METHODS

First cycles of 122 PGT-M patients and 240 controls were included. Cessation interval of hormonal contraceptives was categorized as late cessation (cessation <1 year prior to treatment) or early cessation (>1 year prior to treatment). Endometrial thickness was routinely measured on the day of hCG triggering or 1 day prior. The prevalence of an endometrial lining <8 mm was compared between PGT-M patients and controls. Hormonal contraceptive use (both duration and cessation interval) was compared between both groups. Univariable and multivariable regression analyses were performed to identify risk factors for thin endometrial lining. In addition, cycle and pregnancy outcomes were compared within control/PGT-M groups between patients with endometrial lining > or <8 mm.

MAIN RESULTS AND THE ROLE OF CHANCE

Thin endometrial lining on the day of hCG triggering was found significantly more often in the PGT-M group, compared to controls: 32% vs 11% (mean difference 21.0%, 95% CI: 11.7, 30.3%). As expected, more patients in the PGT-M group ceased their hormonal contraception late (<1 year): 64% vs 2% in the control group (mean difference 61.9%, 95% CI: 53.0, 70.8%). Average duration of hormonal contraceptive use was 10.6 years in the PGT-M group vs 9.3 years in controls (mean difference 1.3 years, 95% CI: 0.2, 2.3 years). Multivariable logistic regression analysis identified late cessation (OR: 6.0, 95% CI: 1.9-19.2) and duration of prior hormonal contraceptive use (OR per year increase 1.1, 95% CI: 1.0-1.2) as significant independent risk factors for a thin endometrial lining. In relation to outcome, we found a statistically significant increase in miscarriage rate in PGT-M patients with an endometrial lining <8 mm compared to those with an endometrial lining >8 mm (20.0% vs 1.7%, mean difference 18.3%, 95% CI: 2.3, 34.3%). A trend towards lower birth weight and gestation- and gender-adjusted birth weight (z-score) was also found in this group. No statistically significant differences were detected in pregnancy rate, live birth rate, or incidence of preterm delivery or SGA. Within the control group, no statistically significant differences were found in outcomes between patients with an endometrial lining <8 compared to an endometrial lining >8 mm.

LIMITATIONS, REASONS FOR CAUTION

The study is retrospective. Various types of hormonal contraceptives were reported which possibly exert different effects on the endometrial lining. In relation to pregnancy outcome measures, numbers were very limited; therefore, no firm conclusions should be drawn.

WIDER IMPLICATIONS OF THE FINDINGS

This study provides further insight into the role of prior hormonal contraceptive use as a possible contributor to the occurrence of thin endometrial lining during ART treatment. Future studies should provide more information on its clinical relevance, to determine whether PGT-M patients can be reassured, or should be counselled to stop hormonal contraceptive use and change to an alternative contraceptive method prior to PGT treatment.

STUDY FUNDING/COMPETING INTERESTS

No specific funding was used and no conflicts of interests are declared.

TRIAL REGISTRATION NUMBER

N/A.

Reproductive Outcomes and Overall Prognosis of Women with Asherman's Syndrome Undergoing IVF

STUDY OBJECTIVE

To evaluate the impact of Asherman syndrome (AS) following hysteroscopic adhesiolysis on reproductive outcomes and the time to achieve pregnancy in women with infertility undergoing in vitro fertilization (IVF) treatment.

DESIGN

Case-control study.

SETTING

Tertiary university-affiliated medical center.

PATIENTS

Fifty-one infertile women who were treated for AS and underwent IVF (study group) matched for age and etiology of infertility with non-AS controls at a 1:1 ratio.

INTERVENTIONS

Medical records search, chart review, and phone survey were used to assess reproductive outcomes.

MEASUREMENTS AND MAIN RESULTS

A multivariate logistic regression analyses was used to assess live birth, accounting for patient age at stimulation cycle start, parity, number of embryos transferred, and endometrial thickness. A survival analysis was performed to assess the times that had lapsed from interventions to conception. The study group of 51 women included 38 (74.5%) with moderate to severe disease. The mean number of embryo transfers per woman was similar for the study and control groups (4.9 ± 4.6 vs 6.22 ± 4.3, respectively, p = .78). The controls had a significantly higher mean endometrial thickness before embryo transfer (8.7 ± 1.8 mm vs 6.95 ± 1.7 mm, p = .001). The overall time to achieve live birth was significantly longer in women with AS (p = .022). In a logistic regression analysis, the presence of moderate to severe AS was shown to be an independent factor for achieving a live birth (adjusted odds ratio 0.174, 95% confidence interval [CI], 0.032-0.955, p = .004). Women with AS who had live births had a significantly thicker mean endometrial thickness (8.2 ± 1.4 mm vs 6.9 ± 1.2, p = .001).

CONCLUSION

Moderate and severe AS has a detrimental effect on reproductive performance in infertile women. Endometrial thickness is an important predictor for live births among women with AS who undergo IVF.

The role of timing in frozen embryo transfer

The process of implantation is characterized by a complex cross-talk between the endometrium and the blastocyst, with the endometrium only being receptive to implantation during a transient window of implantation of approximately 2-3 days during the midsecretory phase. The timing of embryo transfer, including frozen embryo transfer, is therefore critical to the success of implantation. In this article, we discuss various elements that may guide the timing of frozen embryo transfer, including the role of endometrial characteristics such as thickness, days postovulation or length of progesterone administration, stage of the embryo, and the application of endometrial receptivity tests to guide personalized embryo transfer.

Does endometrial thickness affect pregnancy outcomes in isolated male infertility IVF cycles? A retrospective cohort study

In our retrospective cohort study, we aimed to determine the role of endometrial thickness (ET) in isolated male factor infertile women in vitro fertilisation/intracytoplasmic sperm injection (IVF/ICSI) fresh embryo cycles. The patients were classified as having an endometrial thickness of <7 mm (n: 80), 7-9.9 mm (n: 335), 10-14 mm (n: 579) and >14 mm (n: 50) according to their ETs on the human chorionic gonadotropin (hCG) day. The overall clinical pregnancy rate was 37.4%, and no significant difference was found between the groups (p = .262). There was no significant difference between live birth rates (p = .094), but the highest pregnancy (46%) and live birth (34%) rates were found in the group with >14 mm ET. The increase in ET in IVF cycles increases pregnancy rates, albeit partially. When it is desired to determine a cut-off value, it can be said that pregnancy rates increase significantly in thicknesses of 14 mm and above.Impact StatementWhat is already known on this subject? When the literature is examined, many studies conclude that clinical pregnancy rates increase with the increase in endometrial thickness (ET) in IVF cycles, but there are also studies that argue the opposite. There is no study in the literature investigating the effect of ET on clinical pregnancy rates in patients with isolated male factor infertility.What do the results of this study add? In support of the literature, an increase in ET was found to be associated with an increase in clinical pregnancy rates, regardless of male and female factors. Although pregnancy occurs in thin endometriums, abortion rates are undesirably high.What are the implications of these findings for clinical practice and/or further research? Although the risk of abortion is high in thin endometriums, live birth rates are satisfactory. As a result, thin endometrium does not require cycle cancellation.

Pregnancy complications and placental histology following embryo transfer with a thinner endometrium

STUDY QUESTION

Are deliveries following IVF with a thinner endometrium associated with adverse perinatal outcomes and placental findings?

SUMMARY ANSWER

Live births following IVF with a thinner endometrium are associated with an increased rate of placental-mediated obstetric complications and lower birthweight, while the placentas are notable for gross anatomical and histological malperfusion lesions.

WHAT IS KNOWN ALREADY

Past studies have noted a higher rate of adverse outcomes on deliveries following IVF with a thinner endometrium, mainly placental-associated complications. However, no study to date has investigated placental histopathology in such cases.

STUDY DESIGN, SIZE, DURATION

This was a retrospective cohort study of 1057 deliveries following IVF, between 2009 and 2017. All placentas were sent to pathology irrelevant of pregnancy complication status, per protocol at our institution.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Live singleton births from a tertiary university hospital after IVF were compared between patients for whom embryo transfer was performed with an endometrium <9 mm (thinner endometrium group) and patients with an endometrium ≥9 mm (control group). Placental pathologic findings were categorized according to the Amsterdam Placental Workshop Group Consensus. Outcomes were placental findings, including anatomic, inflammatory, vascular malperfusion and villous maturation lesions, as well as obstetric and perinatal outcomes. Continuous and categorical variables were compared as appropriate, and multivariate regression and linear analyses were employed to control for confounders.

MAIN RESULTS AND THE ROLE OF CHANCE

A total 292 cases in the thinner endometrium group, and 765 in the control group were compared. Maternal demographics were non-significant between the groups, except for main fertility indication was more commonly diminished reserve in patients with a thinner endometrium and less commonly male factor, P = 0.003. Higher rates of fresh transfers were noted in the control group, while the thinner endometrium group was notable for higher rates of blastocyte transfers. After adjustment for confounders, deliveries in the thinner endometrium group were associated with an overall higher rate of main placental-mediated complications, 22.9% versus 15.2%, P = 0.003, and significantly lower birthweight, β -100.76 g (-184.4-(-17.0)). Placentas in the thinner endometrium group were notable for reduced thickness and a higher rate of bilobated placentas. Placental histology in the thinner endometrium group demonstrated a higher rate of maternal malperfusion lesions.

LIMITATIONS, REASONS FOR CAUTION

The study was limited by its retrospective design and lack of data regarding prior uterine surgery. In addition, sample size was limited for detection of differences in outcomes of rarer occurrence and for analysis as per a stricter definition of thin endometrium.

WIDER IMPLICATIONS OF THE FINDINGS

Excess obstetric risks should be taken into consideration while planning an embryo transfer with a thinner endometrium. Further studies are needed to assess the yield of cycle cancellation and the effect of potential preventive measures such as Micropirin treatment.

STUDY FUNDING/COMPETING INTEREST(S)

No funding was used and the authors report no conflicting interests.

TRIAL REGISTRATION NUMBER

N/A.

Influence of Maternal Age on the Relationship Between Endometrial Thickness and Ongoing Pregnancy Rates in Frozen-Thawed Embryo Transfer Cycles: A Retrospective Analysis of 2,562 Cycles

Background

In frozen-thawed embryo transfer (FET) cycles, endometrial thickness (EMT) has been used routinely as the main clinical monitoring index. However, the current findings are conflicting.

Method

This was a single-center retrospective study of 2,054 couples (2,562 cycles) who underwent FET (including cleavage stage embryos and blastocysts) between January 2017 and August 2020 in the reproductive centers of First Affiliated Hospital of Xinjiang Medical University. The primary outcome measure was the ongoing pregnancy rate (OPR); the secondary outcome was the clinical pregnancy rate.

Results

After stratified analysis and adjusting for confounders such as maternal age, duration of infertility, number of high-quality embryos transferred, endometrial preparation protocol, number of transfer cycles, and stages of embryo transferred, we found a curvilinear relationship between EMT and the OPR in women < 35 years of age. For women with EMT ≤ 8 mm, the OPR increased by 150% for cleavage stage embryo transfer for every 1 mm increase in the EMT; similarly, it increased by 97% for blastocyst stage FET. However, there was a linear relationship between EMT and OPR in women aged ≥ 35 years. When blastocysts were transferred, for every 1 mm increase in the EMT the OPR increased significantly by 12%. But OPR after frozen-thawed cleavage stage embryos transfer did not increase significantly with increased EMT.

Conclusions

Our study showed that the OPR increased significantly with increased EMT between young women aged < 35 years with EMT ≤ 8 mm and older women who underwent transfer of blastocysts.

GnRH antagonist weakens endometrial stromal cells growth ability by decreasing c-kit receptor expression

BACKGROUND

Several surveys have reported that patients treated with gonadotropin-releasing hormone antagonist (GnRH-ant) protocol showed a significantly lower rate of implantation and clinical pregnancy compared to GnRH agonist (GnRH-a) protocol during in vitro fertilization-fresh embryo transfer. Subsequent studies imputed this poor outcome to the negative effects of GnRH-ant on endometrial receptive. However, the mechanisms were not fully understood.

METHODS

The clinical data of 2815 patients undergoing fresh embryo transfer in our center were analyzed. Human endometrial stromal cells (ESCs) from healthy women undergoing elective pregnancy termination of a normal pregnancy at 8-10 weeks gestation were treated with GnRH-analogs or imatinib (c-kit receptor inhibitor). CCK8 and Flow cytometry were used to investigated the growth ability of ESCs. Immunofluorescence staining and western blot was used to detected the target proteins.

RESULTS

The clinical data showed that the endometrial thickness on HCG Day were significantly lower in GnRH-ant group. Although no difference of embryo quality in these two groups, GnRH-ant group showed remarkably decreased rate of HCG positive, embryo implantation and pregnancy. Moreover, GnRH-ant significantly reduced the proliferation and induced the apoptosis of ESCs. Furthermore, the expression and activation of c-kit receptor, which played pivotal roles during embryo implantation, were observably decreased by GnRH-ant. Inhibiting the activation of c-kit by imatinib remarkably suppressed the proliferation and promoted the apoptosis of ESCs. Additionally, the phosphorylation of AKT and expression of Cyclin D1, which were closely related with cellular growth, were distinctly lessened after treating with imatinib.

CONCLUSIONS

In summary, our study showed that GnRH-ant weakened the activization of c-kit receptor by decreasing its expression, causing the impaired growth ability of ESCs. Our findings provided a new insight into the effects of GnRH-ant on endometrium.

Optimal endometrial thickness in fresh and frozen-thaw in vitro fertilization cycles: an analysis of live birth rates from 96,000 autologous embryo transfers

OBJECTIVE

To study the effect of increasing endometrial thickness on live birth rates in fresh and frozen-thaw embryo transfer (FET) cycles.

DESIGN

Retrospective cohort study.

SETTING

National data from Autologous in vitro fertilization (IVF) embryo transfer and FET cycles in Canada from the Canadian Assisted Reproductive Technology Registry Plus (CARTR Plus) database for records between January 2013 and December 2019.

PATIENTS

Thirty-three Canadians clinics participated in voluntary reporting of IVF and pregnancy outcomes to the Canadian Assisted Reproductive Technology Registry Plus database, and a total of 43,383 fresh and 53,377 frozen transfers were included.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy, pregnancy loss, and live birth rates.

RESULTS

In fresh IVF-embryo transfer cycles, increasing endometrial thickness is associated with significant increases in the mean number of oocytes retrieved, peak estradiol levels, number of usable embryos, clinical pregnancy rates, live birth rates, and mean term singleton birth weights, and a decrease in pregnancy loss rates. However, live birth rates plateau after 10-12 mm. In contrast, in FET cycles live birth rates plateau after the endometrium measures 7-10 mm. The improvement in live birth rates with increasing endometrial thickness was independent of patient age, timing of embryo transfer (e.g., cleavage stage vs. blastocyst stage), or the number of oocytes at retrieval.

CONCLUSIONS

In cycles with a fresh embryo transfer, live birth rates increase significantly until an endometrial thickness of 10-12 mm, while in FET cycles live birth rates plateau after 7-10 mm. However, an endometrial thickness <6 mm was associated clearly with a dramatic reduction in live birth rates in fresh and frozen embryo transfer cycles.

An endometrial receptivity scoring system basing on the endometrial thickness, volume, echo, peristalsis, and blood flow evaluated by ultrasonography

BACKGROUND

Establishing a successful pregnancy depends on the endometrium and the embryo. It is estimated that suboptimal endometrial receptivity account for one-third of implantation failures. Despite the indepth understanding of the processes associated with embryo-endometrial cross-talk, little progress has been achieved for diagnosis and treatments for suboptimal endometrial receptivity.

METHODS

This retrospective study included women undergoing their first frozen-thawed embryo transfer (FET) cycles at our reproductive medicine center from March 2021 to August 2021. Transvaginal three-dimensional (3D) ultrasound was performed in the morning on the day of embryo transfer for all the thawed embryo transfer patients, to evaluate endometrial receptivity, including endometrial thickness, echogenicity, volume, movement and blood flow.

RESULTS

A total number of 562 patients of FET with 315 pregnancies (56.0%) was analyzed. It was found that only the echo of the endometrial central line was different between the pregnant group and non-pregnant group. Other parameters, such as endometrial thickness, volume, endometrial peristalsis, or the endometrial blood flow were not statistically different between the two groups. Then, according to the relationship between the different groups and the clinical pregnancy rate, a score of 0 to 2 was respectively scored. The sum of the scores for the six items was the patient's endometrial receptivity score. It showed that the clinical pregnancy rate increased as the endometrial receptivity score increased, and when the receptivity score reaches at least 5, the clinical pregnancy rate is significantly improved (63.7% versus 49.5%, P=0.001).

CONCLUSION

We developed an endometrial receptivity scoring system and demonstrated its validity. It may aid clinicians in choosing the useful marker in clinical practice and for informing further research.

Serum zinc concentration and risk of adverse outcomes to in vitro fertilization and embryo transfer: A prospective cohort study in northern China

Zinc (Zn) plays an important role in female reproductive health. Few studies have currently assessed the effects of female Zn level on the outcome of in vitro fertilization-embryo transfer (IVF-ET). This study investigated the association between serum Zn concentration and IVF-ET outcomes, and the potential effects of some lifestyles on this association. A prospective cohort study design was adopted, and 305 women undergoing IVF-ET were recruited from two cities, Beijing and Shandong, in northern China. Fasting blood specimens were obtained on the day prior to the first treatment cycle. A questionnaire was used to collect demographic characteristics and lifestyle information. Serum Zn concentration was measured using inductively coupled plasma-mass spectrometry. Female serum Zn levels in Beijing center were found to be significantly higher than those in Shandong center. Women who failed to achieve clinical pregnancy had significantly lower Zn concentrations among Shandong subjects, but not in Beijing or the total participants in both centers. For Beijing participants, no statistically significant associations were found between Zn concentrations and the failure risk of IVF-ET [adjusted relative risk (aRR) = 0.65, 95% confidence interval (CI): 0.37-1.15]. For Shandong participants, lower Zn concentrations (< 610.3 ng/mL) were associated with a 66% increased risk of IVF-ET failure (aRR = 1.66, 95% CI: 1.10-2.51). Also, significantly positive correlations were observed between Zn concentrations and the habitual consumption of two food types, including fresh vegetables and beans or bean products, but this was not the case in Beijing. It was concluded that the effect of serum Zn concentrations on IVF-ET outcome may vary by the geographic location. Lower Zn levels might be a risk factor for IVF-ET failure among Shandong women, which can be addressed by adjusting the food intakes. These findings have implications for human infertility treatment and public health problem addressing.

Associations between ambient air pollution and IVF outcomes in a heavily polluted city in China

RESEARCH QUESTION

Is air pollution related to IVF outcomes in a heavily polluted city in China?

DESIGN

A retrospective cohort study of 8628 fresh, autologous IVF cycles was conducted for the first time at the Reproductive Medicine Center of The Third Affiliated Hospital of Zhengzhou University between May 2014 and December 2018 (oocyte retrieval date). The exposure was divided into four periods (gonadotrophin injection to oocyte retrieval [P1], oocyte retrieval to embryo transfer [P2], 1 day after embryo transfer to embryo transfer +14 days [P3] and gonadotrophin injection to embryo transfer +14 days [P4]) and four levels (Q1-Q4 according to their 25th, 50th and 75th percentiles).

RESULTS

An interquartile range increase (Q2 versus Q1) in particulate matter ≤10 µm (PM10) during P3 and P4 and sulphur dioxide (SO₂) during P3 significantly decreased the clinical pregnancy rate (adjusted odds ratio [aOR] 0.81, 95% confidence interval [CI] 0.71-0.92 for PM10 of P3; aOR 0.87, 95% CI 0.76-1.00 for PM10 of P4; aOR 0.82, 95% CI 0.73-0.93 for SO₂ of P3). In addition, PM10 was associated with an increased biochemical pregnancy rate (Q3 versus Q1: aOR 1.55, 95% CI 1.09-2.19 for PM10 of P1) and decreased live birth rate (Q2 versus Q1: aOR 0.88, 95% CI 0.77-0.99 for PM10 of P3). The multivariate regression results were consistent with that of multiple treatments propensity score method (PSM) for SO₂ pollutants in P3 and PM10 pollutants in P4.

CONCLUSION

From the early follicular stage to the pregnancy test period, high concentrations of PM10 and SO₂ may have a negative impact on IVF treatment outcomes in the study area.

Association between endometrial thickness and birth weight in fresh IVF/ICSI embryo transfers: a retrospective cohort study of 9273 singleton births

RESEARCH QUESTION

What is the association between endometrial thickness (EMT) on HCG trigger day and outcomes related to birth weight in fresh IVF and intracytoplasmic sperm injection (ICSI) embryo transfer cycles?

DESIGN

A retrospective cohort study of 9273 singleton live births born to women undergoing fresh IVF/ICSI cycles in a single centre between January 2014 and December 2018. Multivariable logistic regression was used to investigate the associations between EMT, low birth weight (LBW) and small for gestational age (SGA). Multivariable-adjusted linear regression models incorporating restricted cubic splines were used to investigate the dose-response relationship between EMT, birth weight and birth weight z-score, respectively. An EMT of 8 mm was set as a reference value.

RESULTS

Compared with women with an EMT of 8.0 to < 14.0 mm the risk of delivering a SGA infant was increased with EMT < 8.0 mm (adjusted odds ratio [aOR] 1.78, 95% confidence interval [CI] 1.09 to 2.90) and decreased with EMT ≥ 14.0 mm (aOR 0.57, 95% CI 0.35 to 0.93, respectively). Birth weights of infants born to women with an EMT of 8.0 mm compared with women with EMT of 5.0, 6.0, and 7.0 mm were lower by 120 g (95% CI -175 g to -66 g), 80 g (95% CI -116 g to -44 g), and 40 g (95% CI -58 g to -22 g) respectively; infant birth weight z-scores were also decreased by 0.19 (95% CI -0.27 to -0.10), 0.12 (95% CI -0.18 to -0.07) and 0.06 (95% CI -0.09 to -0.03), respectively.

CONCLUSIONS

A thinner endometrium was associated with lower birth weight and birth weight z-score, and higher risk of SGA. Women with a thin endometrium warrant special attention during pregnancy.

Evaluation of embryo transfer through a scoring system: ETSS (Embryo transfer scoring system)

INTRODUCTION

To create a scoring system by including all of the factors that are recommended for an ideal ET and to investigate its correlation with the Β-HCG results.

MATERIALS AND METHODS

This study was conducted as a retrospective trial between January 2009 and December 2018. Women who had a single ET between the specified dates were included in the study. The embryo grade, ET day, distance between the fundus to embryo transfer site measured via ultrasonography, endometrial thickness on ET day, and presence of mucus and blood in the catheter after transfer were the variables evaluated. Each one of the five variables that constituted the scoring system were rated separately.

RESULTS

Overall, 1652 patients participated in this research. Antral follicle count (13,3 ± 8 vs. 14,6 ± 8,2, p: 0,001), endometrial thickness on the ET day (9.9 ± 2 vs.10.3 ± 2, p = 0.006) and number of mature oocytes (8.6 ± 6 vs. 9 ± 5.1, p: 0.003) were significantly higher in patients with positive Β-HCG values. The total score in the Β-HCG positive group was 9.8 ± 1.4 versus 8.9 ± 1.4 in the Β-HCG negative group (p < 0.001). The best ETSS cut-off value for predicting Β-HCG positivity was 9.5, with 82% sensitivity and 67% specificity (AUC:0.808).

CONCLUSION

Our scoring system is an important step toward standardization, as it offers a new, practical, cost-free, and applicable scoring system based on pre- and post-ET measurements and laboratory data.

Effects of artificial cycles with and without gonadotropin-releasing hormone agonist pretreatment on frozen embryo transfer outcomes in patients with adenomyosis

Gonadotropin-releasing hormone agonist (GnRH-a) is generally added to the improve pregnancy outcomes of hormone replacement therapy cycles among patients with adenomyosis. We aimed to investigate whether adding GnRH-a can result in better pregnancy outcomes. This retrospective analysis included 341 patients with adenomyosis who underwent frozen embryo transfer (FET) after in vitro fertilization (IVF). The control group was treated only with hormone replacement therapy cycles to prepare the endometrium, and GnRH-a was added to the study group before hormone administration to adjust the menstruation cycle. Based on the similar baseline values and embryological data, there was no significant difference in the clinical pregnancy rates (40.63% vs. 42.54%, P = 0.72) and live birth rates (23.75% vs. 23.75%, P = 0.74) of the control and study groups. Other secondary outcomes, including the rates of clinical miscarriage, ectopic pregnancy, preterm birth and term birth, were not significantly different between the two groups. Compared with the hormone replacement therapy cycle alone, GnRH-a downregulation based on a hormone replacement therapy cycle may not increase the rate of clinical pregnancy or live birth of IVF-ET with FET among infertile patients with adenomyosis.

Efficacy and safety of autologous platelet-rich fibrin for the treatment of infertility with intrauterine adhesions

AIM

To evaluate the efficacy and safety of autologous platelet-rich fibrin (PRF) for the treatment of infertility with intrauterine adhesions.

METHODS

Forty patients who suffered from infertility with intrauterine adhesions (IUAs) were enrolled in this prospective trial from October 2018 to December 2019. They were randomly divided into a PRF group and a control group. Both groups underwent transcervical resection of adhesions (TCRA) during the follicular phase. PRF group: PRF prepared from autologous venous blood was placed in the uterine cavity after TCRA and after the first menstrual re-fluid; control group: no PRF insertion. After the second menstrual re-fluid, both groups underwent hysteroscopy to reevaluate adhesion severity. Pregnancy rate, intrauterine adhesion score, menstrual volume and duration, and endometrial thickness were assessed and adverse events were recorded.

RESULTS

(1) PRF group pregnancy rate was significantly higher than the control group (55.0% vs. 20.0%). Mean follow-up time was (17.63 ± 2.33) months. All patients fell pregnant naturally. Four (PRF) and one (control) patients delivered live births without placental complications. (2) Intrauterine adhesion scores decreased compared with treatment-before. (3) In the pictorial blood loss assessment chart, score and menstrual duration during the 3rd menstrual cycle showed significant improvements for both groups. (4) Endometrial thickness also showed an increasing trend, and subendometrial bloodflow improved. (5) No treatment-related serious adverse events were noted.

CONCLUSION

Placing PRF into the uterine cavity of infertility patients with IUAs following TCRA is a safe and effective therapeutic method.

Analysis of endometrial thickness patterns and pregnancy outcomes considering 12,991 fresh IVF cycles

BACKGROUND

Different endometrial patterns have an important effect on the relationship between endometrial thickness (EMT) and clinical pregnancy rate. There is a significant difference in age, selection of cycle protocols, and clinical pregnancy rates among four groups with diverse endometrial patterns.

METHODS

This retrospective study aimed to assess the association between EMT on human chorionic gonadotropin (HCG) administration day and the clinical outcome of fresh in vitro fertilization (IVF). The 5th, 50th, and 95th percentiles for EMT were determined as 8, 11, and 14 mm, respectively. Patients were sub-divided into four groups based on their EMT in different endometrial patterns (Group 1: < 8 mm; Group 2: ≥ 8 and ≤ 11 mm; Group 3: > 11 and ≤ 14 mm; Group 4: > 14 mm). We divided patients into three groups based on their endometrial pattern and evaluated the correlation between EMT and clinical pregnancy rate.

RESULTS

We found a positive correlation between pregnancy rates and EMT in all endometrial patterns. Multiple logistic regression analysis proved age, duration of infertility, cycle protocols, number of embryos transferred, progesterone on HCG day, endometrial patterns, and EMT have significant effects on clinical pregnancy rates. Meanwhile, there was a significant difference in age, selection of cycle protocols, and clinical pregnancy rates among four groups with diverse endometrial patterns.

CONCLUSIONS

Different endometrial patterns have an important effect on the relationship between EMT and clinical pregnancy rate.

Thin endometrium is associated with the risk of hypertensive disorders of pregnancy in fresh IVF/ICSI embryo transfer cycles: a retrospective cohort study of 9,266 singleton births

BACKGROUND

Thin endometrial thickness (EMT) has been suggested to be associated with reduced incidence of pregnancy rate after in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment, but the effect of thin endometrium on obstetric outcome is less investigated. This study aims to determine whether EMT affects the incidence of obstetric complications in fresh IVF/ICSI-embryo transfer (ET) cycles.

METHODS

We conducted a retrospective cohort study collecting a total of 9266 women who had singleton livebirths after fresh IVF/ICSI-ET treatment cycles at the Center for Reproductive Medicine Affiliated to Shandong University between January 2014 and December 2018. The women were divided into three groups according to the EMT: 544 women with an EMT ≤8 mm, 6234 with an EMT > 8-12 mm, and 2488 with an EMT > 12 mm. The primary outcomes were the incidence of obstetric complications including hypertensive disorders of pregnancy (HDP), gestational diabetes mellitus (GDM), placental abruption, placenta previa, postpartum hemorrhage (PPH) and cesarean section. Multivariable logistic regression analysis was performed to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for associations between the EMT measured on the day of human chorionic gonadotropin (HCG) trigger and the risk of the outcomes of interest.

RESULTS

The HDP incidence rate of pregnant women was highest in EMT ≤ 8 mm group and significantly higher than those in EMT from > 8-12 mm and EMT > 12 mm group, respectively (6.8% versus 3.6 and 3.5%, respectively; P = 0.001). After adjustment for confounding variables by multivariate logistic regression analysis, a thin EMT was still statistically significant associated with an increased risk of HDP. Compared with women with an EMT > 8-12 mm, women with an EMT ≤8 mm had an increased risk of HDP (aOR = 1.853, 95% CI 1.281-2.679, P = 0.001).

CONCLUSION

A thin endometrium (≤8 mm) was found to be associated with an increased risk of HDP after adjustment for confounding variables, indicating that the thin endometrium itself is a risk factor for HDP. Obstetricians should remain aware of the possibility of HDP when women with a thin EMT achieve pregnancy through fresh IVF/ICSI-ET treatment cycles.

Association between exposure of light rare earth elements and outcomes of in vitro fertilization-embryo transfer in North China

The adverse health effects of rare earth elements (REEs) on reproductive health remain a subject of debate, and few clinical observations are available. This study investigated the association between light REEs (LREEs) exposure and the outcome of in vitro fertilization-embryo transfer (IVF-ET). We recruited a total of 305 women undergoing IVF-ET in Beijing City and Shandong Province of northern China. Their demographic information and lifestyle characteristics were collected using questionnaires at enrollment. Fasting blood samples were collected on the day before the IVF-ET treatment cycle began. Serum concentrations of the LREEs of concern were analyzed using inductively coupled plasma-mass spectrometry, and four LREEs were measured with a high detection rate, including lanthanum (La), cerium (Ce), praseodymium (Pr), and neodymium (Nd). We found that a higher serum La concentration was associated with a 30% increased likelihood of clinical pregnancy failure [relative risk (RR) = 1.30, 95% confidence interval (CI): 1.00-1.67] and a 230% increased likelihood of preclinical spontaneous abortion (RR = 3.30, 95% CI: 1.57-6.94). There was a negative correlation between serum La concentration and the number of good-quality oocytes. For the other LREEs, no statistically significant associations were observed. We concluded that a high serum La concentration may have an adverse effect on IVF-ET outcomes.

Endometrial regeneration with endometrial epithelium: homologous orchestration with endometrial stroma as a feeder

BACKGROUND

Thin endometrium adversely affects reproductive success rates with fertility treatment. Autologous transplantation of exogenously prepared endometrium can be a promising therapeutic option for thin endometrium; however, endometrial epithelial cells have limited expansion potential, which needs to be overcome in order to make regenerative medicine a therapeutic strategy for refractory thin endometrium. Here, we aimed to perform long-term culture of endometrial epithelial cells in vitro.

METHODS

We prepared primary human endometrial epithelial cells and endometrial stromal cells and investigated whether endometrial stromal cells and human embryonic stem cell-derived feeder cells could support proliferation of endometrial epithelial cells. We also investigated whether three-dimensional culture can be achieved using thawed endometrial epithelial cells and endometrial stromal cells.

RESULTS

Co-cultivation with the feeder cells dramatically increased the proliferation rate of the endometrial epithelial cells. We serially passaged the endometrial epithelial cells on mouse embryonic fibroblasts up to passage 6 for 4 months. Among the human-derived feeder cells, endometrial stromal cells exhibited the best feeder activity for proliferation of the endometrial epithelial cells. We continued to propagate the endometrial epithelial cells on endometrial stromal cells up to passage 5 for 81 days. Furthermore, endometrial epithelium and stroma, after the freeze-thaw procedure and sequential culture, were able to establish an endometrial three-dimensional model.

CONCLUSIONS

We herein established a model of in vitro cultured endometrium as a potential therapeutic option for refractory thin endometrium. The three-dimensional culture model with endometrial epithelial and stromal cell orchestration via cytokines, membrane-bound molecules, extracellular matrices, and gap junction will provide a new framework for exploring the mechanisms underlying the phenomenon of implantation. Additionally, modified embryo culture, so-called "in vitro implantation", will be possible therapeutic approaches in fertility treatment.

The predictive value of endometrial thickness in 3117 fresh IVF/ICSI cycles for ectopic pregnancy

OBJECTIVES

To evaluate the predictive value of endometrial thickness (EMT) during in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles for ectopic pregnancy (EP).

METHODS

A total of 3068 patients with 3117 fresh IVF/ICSI cycles between January 2016 and February 2019 from the Reproductive Medicine Center of Sun Yat-Sen Memorial Hospital were included in this retrospective study. The patients were divided into an EP group (n = 92) and an intrauterine pregnancy (IUP) group (n = 3025). Multiple logistic regression analysis was conducted to evaluate the EP risk factors. Receiver operating characteristic (ROC) curves were used to evaluate the predictive value of the risk factors for EP and calculate the cutoff value of EMT for EP prediction.

RESULTS

The incidence rate of EP was 2.95 % (92/3117). After adjustment for other factors in the logistic regression model, the incidence of EP decreased by 55 % with an EMT > 10 mm compared with an EMT ≤ 10 mm (odds ratio 0.450, 95 % confidence interval 0.296-0.684, P < 0.001). The EMT in the EP group was significantly thinner than that in the live birth (n = 2540) and spontaneous abortion (n = 485) groups (p < 0.017). The cutoff value of EMT for EP prediction was 10.65 mm, with a sensitivity of 59 % and a specificity of 63 %.

CONCLUSION

A decreased risk of EP was found among the patients with an EMT > 10 mm prior to embryo transfer. A certain EMT is needed to reduce the incidence of EP.

The relationship and optimal threshold of endometrial thickness with early clinical pregnancy in frozen embryo transfer cycles

OBJECTIVE

To investigate the associations of endometrial thickness with pregnancy outcome in frozen embryo transfer (FET) cycles.

METHODS

A retrospective cohort study was performed looking at 1627 FET cycles from the Reproductive Medicine Center of the study hospital between January 2017 and July 2018. Endometrial ultrasonographic characteristics were recorded on the embryo transfer day in FET cycles.

RESULTS

A total of 1627 FET cycles were included. The endometrial thickness was independently associated with clinical pregnancy outcomes after adjusting for potential confounders (odds ratio 1.06; 95% confidence interval [CI] 1.01-1.12). A non-linear relationship was detected between endometrial thickness and pregnancy outcomes, whose point was 10.9 mm. The effect size of the left and right sides of the inflection point were 1.16 (95% CI 1.07-1.25) and 0.89 (95% CI 0.78-1.01), respectively. Subgroup analysis showed that the correlation between endometrial thickness and pregnancy outcome was consistent in all subgroups.

CONCLUSION

The relationship between endometrial thickness and pregnancy outcome was non-linear and there is an inflection point. When endometrial thickness was less than 9.5 mm, it was positively related to clinical pregnancy rate. If it was beyond the inflection point, the pregnancy rate does not increase significantly.

The Effects of Endometrial Thickness on Pregnancy Outcomes of Fresh IVF/ICSI Embryo Transfer Cycles: An Analysis of Over 40,000 Cycles Among Five Reproductive Centers in China

OBJECTIVE

To investigate the effects of endometrial thickness (EMT) on pregnancy outcomes on hCG trigger day in fresh in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycles.

METHODS

A total of 42,132 fresh cycles between 1 January 2013 and 31 December 2019 were included in this retrospective cohort study. Data were collected from five reproductive centers of large academic or university hospitals in China. All patients were divided into different groups according to their endometrial thickness on hCG trigger day. Multivariate regression analysis, curve fitting and threshold effect analysis were performed.

RESULTS

After adjusting for age, body mass index, infertility type, number of embryos transferred, number of retrieved oocytes and COS (controlled ovarian stimulation) protocols, significant associations were found between endometrial thickness and clinical pregnancy rate (adjusted odds ratio [aOR]: 1.05; 95% confidence interval [CI]: 1.06-1.08, P < 0.0001), live birth rate (aOR: 1.04; 95% CI: 1.03-1.05, P < 0.0001) as well as miscarriage rate(aOR: 0.96; 95% CI: 0.94 - 0.98, P < 0.0001). When the endometrial thickness was less than 12mm, the clinical pregnancy rate and live birth rate were increased significantly by 10% and 9%(OR:1.10; 95%CI: 1.08-1.12, OR:1.09; 95%CI: 1.07-1.11), respectively, along with the increase of each millimeter increment of endometrial thickness. However, when the EMT ranged from 12-15 mm, were stable at the ideal level, that were not significantly associated with EMT growth. Additionally, clinical pregnancy rate and live birth rate were slightly reduced by 6% and 4% when EMT was ≥15mm. Meanwhile, the miscarriage rate was significantly declined by 8% (OR:0.92; 95%CI: 0.90-0.95)with each millimeter increment of EMT. And when EMT was thicker than 12mm, the miscarriage rate didn't change any more significantly.

CONCLUSIONS

Endometrial thickness exhibits a curvilinear relationship with pregnancy outcomes in fresh embryo transfer cycles. Clinical pregnancy rate, live birth rate and miscarriage rate may achieve their optimal level when EMT ≥ 12 mm, but some adverse pregnancy outcomes would be observed when EMT ≥15 mm especially for clinical pregnancy.

Interactions of Cortisol and Prolactin with Other Selected Menstrual Cycle Hormones Affecting the Chances of Conception in Infertile Women

One of the major problems of success in infertility treatment could depend on the understanding how the potential factors may affect the conception. The aim of this study was to evaluate present understanding of such factors or hormonal causes that may induce infertility. We studied the interactions between the two menstrual cycle hormones i.e., cortisol (COR) and prolactin (PRL), along with the ultrasonographic ovulation parameters in a group of N = 205 women with diagnosed infertility. The control group consisted of N = 100 women with confirmed fertility. In both groups, follicle-stimulating hormone (FSH), luteinizing hormone (LH), anti-Müllerian hormone (AMH), thyroid stimulating hormone (TSH), PRL, COR were examined on the third day of the cycle, and estradiol (E2), progesterone (P), and COR were examined during ovulation and 7-days afterwards. In the infertile group, higher levels of PRL and COR were observed than that of in the control group. Cortisol levels at all phases of the menstrual cycle and PRL negatively correlated with E2 secretion during and after ovulation, thus contributed to the attenuation of the ovulatory LH surge. Infertile women who conceived presented with higher levels of E2 during and after ovulation, higher P after ovulation, and thicker endometrium than that of the women who failed to conceive. In conclusion, elevated secretion of COR and PRL in infertile women impairs the menstrual cycle by decreasing the pre-ovulatory LH peak and E2 and postovulatory E2 levels that affect the endometrial growth, and consequently reduce the chances to conceive.

Comparison of GnRH-a Prolonged Protocol and Short GnRH-a Long Protocol in Patients with Thin Endometrium for Assisted Reproduction: A Retrospective Cohort Study

Purpose

Gonadotrophin releasing hormone agonist (GnRH-a) is widely used for pituitary down-regulation and recruiting more follicles in assisted reproduction. However, no information is available on its value for patients with thin endometrial thickness.

Patients and Methods

This was a retrospective cohort study of 302 patients with endometrium <8 mm undergoing fresh embryo transfer at a fertility center of a university hospital from January 2016 and December 2018. In 148 cycles of the GnRH-a prolonged protocol, one depot of 3.75 mg GnRH-a was injected on day 2 of the menstrual cycle, while in 154 cycles of the short GnRH-a long protocol, 0.1 mg of GnRH-a was injected daily from the mid-luteal phase. The live birth rate and clinical pregnancy rate were compared between the two groups. Other outcome measures included the implantation rate, miscarriage rate, and characteristics of stimulation procedures.

Results

Live birth rates and clinical pregnancy rates were significantly higher in the GnRH-a prolonged protocol group than in the other group (36.5% vs 20.8%, P=0.002; 43.9% vs 28.2%, P=0.006, respectively). The live birth rate was significantly increased in the prolonged protocol group (crude OR: 2.190, 95% CI: 1.311, 3.660; adjusted OR: 2.458, 95% CI: 1.430, 4.224) compared with that in the reference group. The implantation rate of the former group was also significantly higher than that of the latter group (35.4% vs 15.9%, P=0.000). There was no significant difference in miscarriage rates between the two protocols. In terms of stimulation procedures, the GnRH-a prolonged protocol group required significantly higher Gn time (10.9 vs 9.5 days, P=0.000) and Gn consumption (2625.0 vs 2047.5 IU, P=0.000) than the short GnRH-a long protocol group.

Conclusion

The GnRH-a prolonged protocol in fresh embryo transfer cycles yielded better clinical outcomes of patients with thin endometrium than the short GnRH-a long protocol.

Value of endometrial thickness change after human chorionic gonadotrophin administration in predicting pregnancy outcome following fresh transfer in vitro fertilization cycles

PURPOSE

To study whether the change of endometrial thickness (EMT) between the day of human chorionic gonadotrophin (hCG) administration and the day of embryo transfer has any impact on pregnancy outcome in fresh in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles.

METHODS

This single-center retrospective cohort study included 2620 patients undergoing their first consecutive autologous IVF/ICSI cycles from January 2003 to December 2012. Patients were categorized into three groups based on the percentage change of post-hCG EMT: > 10% decrease, ± 10% plateau and > 10% increase. The primary outcome was live birth rate.

RESULTS

Live birth rates were similar in the EMT decrease, plateau and increase groups (27.4% [174/635], 29.7% [300/1010] and 27.6% [269/975]; P = 0.649). Compared with the plateau group, both EMT decrease (crude odds ratio [cOR] 0.89, 95% confidence interval [CI] 0.72-1.11) and increase (cOR 0.90, 95% CI 0.74-1.10) on the day of transfer did not affect the likelihood of live birth. The non-significant association was maintained after controlling for major confounding factors, with the adjusted OR being 0.92 (95% CI 0.73-1.16) and 0.92 (95% CI 0.75-1.13) for the decrease and increase groups, respectively.

CONCLUSION

EMT change after hCG administration did not provide significant prognostic information for pregnancy outcome in fresh IVF/ICSI cycles. This finding should offer reassuring information for patients with decreased EMT on the day of embryo transfer while questioning the necessity of EMT re-measurement prior to transfer as a routine practice.