Do Endometrial Movements Affect The Achievement of Pregnancy during Intrauterine Insemination?

Endometrial Elasticity is an Ultrasound Marker for Predicting Clinical Pregnancy Outcomes after Embryo Transfer

Endometrial elasticity is a potential new marker for assessing endometrial receptivity and pregnancy outcomes based on endometrial thickness and type. Currently, little research has been conducted on the elasticity of the endometrium using shear wave elasticity imaging (SWEI). This study aimed to explore whether endometrial elasticity is an ultrasound marker for predicting clinical pregnancy outcomes after embryo transfer. A total of 245 infertile women underwent ultrasonography before embryo transfer at the Peking University Third Hospital. We compared the endometrial elasticity and sub-endometrial blood flow rate using SWEI in the groups with different pregnancy outcomes. Trends in clinical pregnancy outcomes across the quartiles of endometrial elasticity in the fundus of the uterus (E1) were assessed. Logistic regression analysis was performed to obtain odds ratios for clinical pregnancy outcomes based on the quartiles of E1, with or without adjusting for potential confounding variables. Women in the clinical pregnancy group had higher E1 values and sub-endometrial blood flow rates in the uterine fundus than those in the non-pregnancy group. Women in the highest quartile of E1 had the most favorable clinical pregnancy rates. Endometrial elasticity measured using SWEI is a promising ultrasound marker for predicting clinical pregnancy outcomes after embryo transfer.

The Effect of Uterine Contractions on Fertility Outcomes in Frozen Embryo Transfer Cycles: A Cohort Study

Background

The relationship between uterine peristalsis before embryo transfer and the success of assisted reproductive techniques (ARTs) has not been properly investigated. In this study, the effect of uterine contractions on embryo implantation in frozen embryo transfer (FET) cycles was investigated to determine whether the frequency of uterine contractions can be used as a quantitative marker to assess endometrial receptivity.

Methods

In this cohort study of 68 eligible FET candidates, one hour before embryo transfer (ET), frequency of uterine contractions was assessed with transvaginal ultrasonography. Patients were followed up for 20 weeks. The association between FET outcomes including clinical pregnancy, abortion, and ectopic pregnancy with uterine contractions was evaluated. Binary logistic regression was conducted to test the association between clinical pregnancy outcomes in different groups. The p<0.05 were considered statistically significant.

Results

Of 68 patients, 25 (36.8%) experienced clinical pregnancy. Multiple logistic regression for omitted confounders (age, BMI, duration, type and cause of infertility) revealed that patients with uterine peristaltic wave frequency less than 2≤ wave/min had higher chance of successful pregnancy compared to those with ≥4 wave/min (odds ratio: 10.8; 95% confidence interval: 1.5-79.4, p=0.019). The Pearson's correlation showed a statistically significant relationship between the frequency of uterine contraction and endometrial thickness (r= 0.42, p=0.002).

Conclusion

Patients with uterine peristalsis of <4.0 wave/min before embryo transfer had a higher chance of successful implantation and pregnancy compared with those with higher contraction frequencies. It seems that measuring uterine contraction frequency before embryo transfer might help to predict pregnancy outcomes.

Pregnancy rate in intrauterine insemination, is uterine biophysical profile of predictive value? A prospective study

PURPOSE

This study aimed at evaluating the value of uterine biophysical profile (UBP) scoring to predict the pregnancy rate after IUI.

METHODS

This prospective study was carried out on 85 women who were referred to our tertiary teaching center with infertility of male factor or unknown etiology infertility in 2018. To measure the uterine biophysical criteria, transvaginal ultrasonography (TVS) was performed on the day of beta-human chorionic gonadotropin (B-hCG) injection, and the results were evaluated based on positive B-hCG.

RESULTS

85 patients were included with a mean age of 30 years; of those 12 (14.1%) were able to conceive. UBP (p = 0.151) and it's parameters (including endometrial thickness, number of endometrial layers, myometrial echogenicity, uterine artery pulsatility index, myometrial blood flow internal to arcuate vessels, endometrial blood flow in the third zone of endometrium, myometrial contraction frequency, and ovarian follicle (OF) size [p = 0.05, 0.89, 0.59, 0.79, 1, 1, 0.59, and 0.77, respectively]) were not significantly associated with pregnancy rate. 91.7% of the cases with positive pregnancy test results, had a UBP score of > 13; however, UBP score was not meaningfully associated with IUI treatment success rate (p = 0.15).

CONCLUSIONS

UBP scoring system seems to need more data for external validation, or it might require modifications before implementation, as it may cause false reassurance.

A predictive model for first-trimester pregnancy inception after IVF-ET based on multimodal ultrasound evaluation of endometrial receptivity

Background

In-vitro fertilization-embryo transfer (IVF-ET) is a commonly used assisted reproductive technology. Its success depends on many factors, including endometrial receptivity. Endometrial receptivity can be evaluated by ultrasound, endometrial biopsy, and magnetic resonance imaging. Compared with the latter two methods, ultrasound has the advantages of wide availability, non-invasiveness, and low cost. Three-dimensional (3D) ultrasound imaging examines endometrial thickness, morphology, and blood vessels, which are associated with the success of embryo implantation. However, there are no reports of endometrial receptivity assessment by 3D ultrasound. Therefore, we aimed to evaluate endometrial receptivity using 3D ultrasound and construct a predictive model for first-trimester pregnancy inception following IVF-ET.

Methods

We performed a prospective observational study on infertile women who underwent IVF-ET between December 2019 and February 2021. These women had 3D ultrasound evaluations, measuring endometrial thickness, volume, pattern, morphology, peristalsis, uterine artery blood flow index, sub-endometrial blood flow index, and distribution pattern. We recorded the occurrence of first-trimester pregnancies in these women. Using Akaike information criterion (AIC) and backward stepwise regression, a first-trimester pregnancy prediction model was constructed based on the minimum AIC value and validated internally and externally.

Results

111 women were enrolled, with 103 included in the analysis. Univariate and multiple logistic regression analyses showed that endometrial thickness and vascularization flow index (VFI) were independent factors associated with the occurrence of a pregnancy. The final prediction model corresponding to the minimum AIC value (65.166) was Y = − 6.131–0.182endometrial thickness + 0.542endometrial volume + 4.374VFI + 0.132age. In the test set, modeling cohort, and external validation cohort, the model showed satisfactory differentiation, with C index of 0.841 (95%CI 0.699–0.817), 0.727 (95%CI 0.619–0.815), and 0.745 (95%CI 0.671–0.840), respectively. The Hosmer–Lemeshow goodness of fit tests reported P = 0.865, 0.139, and 0.070, respectively, indicating a high agreement with the actual IVF-ET outcome. This model reached the highest diagnostic efficiency (sensitivity 88.9%, specificity 75%, Youden index 0.639) at a diagnostic cut-off value of ≥ 0.360.

Conclusions

The predictive model based on endometrial receptivity evaluations by 3D ultrasound had high diagnostic efficiency and could be a simple and effective tool to predict first-trimester pregnancy inception after IVF-ET.

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.

The Role of Abnormal Uterine Junction Zone in the Occurrence and Development of Adenomyosis

Adenomyosis is a benign disease with a malignant behavior, bothering a lot of women at reproductive age who suffer from increased menstruation, prolonged menstruation, progressive dysmenorrhea, and infertility. At present, there is no effective treatment for adenomyosis. It seriously affects the life quality of these patients. However, the pathogenesis of adenomyosis is not yet clear. Recently, uterus junctional zone, defined as the inner 1/3 of myometrium between endometrium and myometrium, has gained broad attention. As is reported, the structure and function disorder of uterus junctional zone may play an important part in the occurrence and development of adenomyosis. In this issue, the present study generally reviews the role of uterine junction zone and the related mechanisms involved in adenomyosis, such as the local micro-damage, the formation of inflammatory and hypoxic microenvironment, changes of cytokines, and abnormalities of miRNA as well as signal pathways. It will provide new insights and potential therapeutic target strategies for clinical strategies in the management of adenomyosis.

The importance of the junctional zone of the endometrium in human reproduction

Junctional zone endometrium (JZE) thickness and contractility seem to determine gamete and embryo transportation and implantation. Proper function depends on concentration levels, mode and timing of oestrogen and progesterone production. Most probably, the remodelling of spiral arteries, and the development of endometrium and decidua are also highly dependent on JZE activity. Fibroids that are adjacent to JZE affect JZE contractility contributing to abnormal or failed implantation. Disruption of the JZE continuity provokes adenomyosis, a condition that causes chronic inflammation and fibrosis, which negatively affects the normal function of JZE. Imaging by magnetic resonance imaging and three-dimensional sonography can diagnose JZE abnormal appearance, alterations in thickening and contractility frequency, usually in the advanced stage of the disease. Failures of assisted reproduction, and adverse early pregnancy outcomes have also been associated with abnormal JZE. Altered uterine contractions due to JZE changes are strongly associated with poor reproductive outcome and early pregnancy loss. Endometriosis and adenomyosis prevalently co-exist, with clear relation and negative effects on the JZE. The presence of endometriosis should alert to the possibility of coexisting adenomyosis. Co-existence of endometriosis may mask the extent of the negative impact of adenomyosis in infertility.

Phenylephrine, a common cold remedy active ingredient, suppresses uterine contractions through cAMP signalling

Regulation of uterine contractility is an important aspect of women’s health. Phenylephrine, a selective agonist of the α₁-adrenoceptor and a potent smooth muscle constrictor, is widely used in women even during pregnancy to relieve cold-related symptoms, to treat postpartum haemorrhoid, and during routine eye exams. We performed isometric tension recordings to investigate the effect of phenylephrine on mouse uterine contractility. Phenylephrine decreased spontaneous and oxytocin-induced contractions in non-pregnant mouse uterine rings and strips with an IC₅₀ of ~1 μM. Prazosin, an inhibitor of α₁-adrenoceptor, did not prevent phenylephrine-mediated relaxations. Conversely, ICI118551, an antagonist of β2-adrenoceptors, inhibited phenylephrine relaxation. In the presence of ICI118551, high concentrations (>30 μM) of phenylephrine caused mouse uterine contractions, suggesting that β-adrenoceptor-mediated inhibition interferes with the phenylephrine contractile potential. Phenylephrine-dependent relaxation was reduced in the uterus of pregnant mice. We used primary mouse and human uterine smooth muscle cells (M/HUSMC) to establish the underlying mechanisms. Phenylephrine stimulated large increases in intracellular cAMP in M/HUSMCs. These cAMP transients were decreased when HUSMCs were cultured in the presence of oestrogen and progesterone to mimic the pregnancy milieu. Thus, phenylephrine is a strong relaxant in the non-pregnant mouse uterus, but exhibits diminished effect in the pregnant uterus.