Natural killer cell subsets in endometrial fluid: a pilot study of their association with the endometrial cycle and reproductive parameters

PURPOSE

To investigate if there are natural killer (NK) cells in endometrial fluid (EF) and their relationship with the endometrial cycle and reproductive parameters.

METHODS

The population under study consisted of 43 women aged 18-40 undergoing infertility workup at our University Hospital in 2021-2022. The EF samples were obtained at the first visit to our unit, on occasion of the mock embryo transfer. The day of the cycle was considered only in cycles of 27-29 days. An immunophenotype study of NK in EF was performed by flow cytometry analysis. In a subgroup of women, on the same day, NK was studied in EF and peripheral blood.

RESULTS

Our study is the first to evidence NK cells in EF. None of the NK cells observed corresponded to a mature peripheral blood NK cell population (stages 4-5), and neither endometrial nor decidual uNK cells were detected. Nevertheless, we found 2 patient groups with an NK cell subset with a higher expression of CD16+, which could belong to an intermediate or transient stage between the uNK and pbNK NK cell population in the EF. We found that CD16 was significantly increased in the mid-late luteal phase and its correlation with the day of the cycle. The NK immunophenotype was different in EF and peripheral blood.

CONCLUSION

We described a new component of the EF, the NK cells, whose CD16 activity is closely correlated with the day of the cycle. These cells could play a role in implantation/implantation failure.

Aspiration with Diosmin Intake in Endometrial Cavity Fluid Accumulation in ART Cycles: A Randomized Controlled Trial

Background

This was a prospective randomized controlled trial in 200 cases presented with endometrial cavity fluid at the day of oocyte retrieval at a private fertility center from 2013 to 2021. The cases were randomized at day of ovum pickup into 2 groups: Group 1 (control group) (n = 100): conventional management with follow-up and reassessment by transvaginal ultrasound on day 5. Group 2 (interventional group) (n = 100): aspiration of the fluid was done and cases were given diosmin 500 mg 3 times per day till reassessment at embryo transfer day. In both groups, we proceeded with fresh embryo transfer if no fluid is present on day 5 or freeze-all policy if persistent fluid was detected.

Results

Endometrial fluid on the 5th day was significantly higher in the control group (28.0%) than in the interventional group (6.0%) (P < 0.001). Regarding pregnancy rate, although being higher in the interventional group (54.3% vs 50.0%), the difference was not statistically significant (P = 0.5). It was found that the intervention was associated with risk reduction of endometrial fluid (OR = 0.168, 95% CI = 0.065-0.429, P < 0.001.

Conclusion

Aspiration of endometrial cavity fluid with diosmin intake increased the likelihood of fresh embryo transfer and with a slightly better pregnancy rate compared to conservative management.Clinical trial number: NCT02158000, Date of registration: 6/6/2014, Date of initial enrollment (first patient recruiting): 1/11/2014, URL: https://clinicaltrials.gov/ct2/show/NCT02158000.

Risk factors for the development of endometrial fluid in women undergoing IVF: A retrospective cohort study✰

RESEARCH QUESTION

Presence of endometrial fluid (EF) is a poorly understood pathology and remains a challenge for clinicians, as very little data exists to explain its consequences and treatment. Our objective was to investigate risk factors for EF during IVF.

DESIGN

This retrospective cohort study included all women with a freeze all embryos cycle (FAE) for EF between 2010 and 2016 at a university-affiliated private IVF center. Controls (2:1) were randomly selected out of the database of our fresh autologous IVF cycles during the same period. Main outcome measures were possible risk factors for EF, comprising polycystic ovarian syndrome (PCOS), ovarian hyperstimulation syndrome (OHSS), previous pelvic or endometrial surgery (polypectomy or synechia removal), cesarean section, myomas and severe endometriosis. A logistic regression model was used to assess independent risk factors for EF.

RESULTS

Out of 9000 IVF cycles, 1204 were FAE cycles, among which we identified 86 EF cases. We then selected 171 controls. Independent risk factors for presence of EF were a history of previous myomectomy (adjusted odds ratio (aOR) 19.77, 95%CI [4.01-97.53]), severe endometriosis (aOR 5.97, 95%CI [2.09-17.05]), PCOS (aOR 5.72, 95%CI [2.66-12.33]) and previous cesarean section (aOR 5.17, 95%CI [1.84-14.49]).

CONCLUSIONS

Our results are not only confirming the association between PCOS, severe endometriosis, previous cesarean procedure and EF, but also reporting for the first time an association between previous myomectomy and EF.

In freeze-all embryo cycles due to endometrial fluid (EF), live birth rates are comparable to those of controls, despite high rates of EF recurrence and cycle cancellation

RESEARCH QUESTION

Do cumulative live birth rates (CLBRs) differ between women who have had a freeze-all embryo cycle (FAE) for endometrial fluid (EF) and controls?

DESIGN

This retrospective cohort study included 83 women who had a FAE cycle due to the presence of EF between 2010 and 2016 at a university-affiliated private IVF center. The controls were 219 women who had FAE for other indications during the same period and were randomly selected. The main outcome measures were CLBRs, EF recurrence, cancellation and pregnancy loss rates.

RESULTS

Population characteristics were comparable between the two groups. The CLBR was not significantly different between the EF and the control group: 39.8 % vs. 47.0 %, respectively, p=0.26. Cancellation rates in the two first FETs were higher in the EF group than the control group: 18.1 % vs. 4.1 % (p<0.001) and 22.9 % vs. 8.5 % (p=0.02). After FAE for EF, we observed a significant risk of EF recurrence (32/177 cycles, 18.1 %), allowing us to identify a poor prognosis subgroup. When EF was detected, the LBR per transfer was 7.1 % (1/14) when the transfer was finally performed (after EF aspiration or EF disappearance), compared to 25 % (32/128) in cycles without EF recurrence (p<0.05). Conversely, in the absence of EF recurrence (145/177, 81.9 %), the LBR was comparable to that of the control group. The type of endometrial preparation does not seem to be associated with EF recurrence.

CONCLUSION

Despite higher rates of EF recurrence and cycle cancellation, women with FAE for EF ultimately have comparable LBRs to those who have had a FAE for other indications. However, women presenting with at least one EF recurrence during FETs seem to have a lower LBR.

The lipidome of endometrial fluid differs between implantative and non-implantative IVF cycles

OBJECTIVE

To characterize the most relevant changes in the lipidome of endometrial fluid aspirate (EFA) in non-implantative cycles.

DESIGN

Lipidomics in a prospective cohort study.

SETTINGS

Reproductive unit of a university hospital.

PATIENTS

Twenty-nine women undergoing an IVF cycle. Fifteen achieved pregnancy and 14 did not.

INTERVENTION

Endometrial fluid aspiration immediately before performing embryo transfer.

MAIN OUTCOME MEASURES

Clinical pregnancy rate and lipidomic profiles obtained on an ultra-high performance liquid chromatography coupled to time-of-flight mass spectrometry (UHPLC-ToF-MS)-based analytical platform.

RESULTS

The comparative analysis of the lipidomic patterns of endometrial fluid in implantative and non-implantative IVF cycles revealed eight altered metabolites: seven glycerophospholipids and an omega-6 polyunsaturated fatty acid. Then, women with a non-implantative cycle were accurately classified with a support vector machine algorithm including these eight lipid metabolites. The diagnostic performances of the algorithm showed an area under the receiver operating characteristic curve, sensitivity, specificity, and accuracy of 0.893 ± 0.07, 85.7%, 80.0%, and 82.8%, respectively.

CONCLUSION

A predictive lipidomic signature linked to the implantative status of the endometrial fluid has been found.

Hsa-miR-30d, secreted by the human endometrium, is taken up by the pre-implantation embryo and might modify its transcriptome

During embryo implantation, the blastocyst interacts with and regulates the endometrium, and endometrial fluid secreted by the endometrial epithelium nurtures the embryo. Here, we propose that maternal microRNAs (miRNAs) might act as transcriptomic modifier of the pre-implantation embryo. Microarray profiling revealed that six of 27 specific, maternal miRNAs were differentially expressed in the human endometrial epithelium during the window of implantation--a brief phase of endometrial receptivity to the blastocyst--and were released into the endometrial fluid. Further investigation revealed that hsa-miR-30d, the expression levels of which were most significantly upregulated, was secreted as an exosome-associated molecule. Exosome-associated and free hsa-miR-30d was internalized by mouse embryos via the trophectoderm, resulting in an indirect overexpression of genes encoding for certain molecules involved in the murine embryonic adhesion phenomenon--Itgb3, Itga7 and Cdh5. Indeed, this finding was supported by evidence in vitro: treating murine embryos with miR-30d resulted in a notable increase in embryo adhesion. Our results suggest a model in which maternal endometrial miRNAs act as transcriptomic modifiers of the pre-implantation embryo.

The utility of endometrial thickness measurement in asymptomatic postmenopausal women with endometrial fluid

The aim of this study was to assess the clinical usefulness of sonographic endometrium thickness measurement in asymptomatic postmenopausal women with endometrial fluid collection. Fifty-two asymptomatic postmenopausal women with endometrial fluid, who underwent endometrial sampling were evaluated. Histopathological findings revealed that 25 (48.1%) women had insufficient tissue, 20 (38.4%) had atrophic endometrium and 7 (13.5%) had endometrial polyps. No case of malignancy was found. There was no statistically significant difference between the various histopathological categories (insufficient tissue, atrophic endometrium and polyp) with regard to the mean single-layer endometrial thickness (1.54 ± 0.87, 2.04 ± 1.76 and 1.79 ± 0.69 mm, respectively, p = 0.436). Out of 44 patients with endometrial thickness of less than 3 mm, 38 (86.4%) had atrophic changes or insufficient tissue and 6 (13.6%) had endometrial polyps. In conclusion, if the endometrial thickness is 3 mm or less, endometrial sampling is not necessary in asymptomatic postmenopausal women with endometrial fluid.

Endometrial fluid associated with Essure implants placed before in vitro fertilization: Considerations for patient counseling and surgical management

Essure (Bayer) received approval from the U.S. Food and Drugs Administration as a permanent non-hormonal contraceptive implant in November 2002. While the use of Essure in the management of hydrosalpinx prior to in vitro fertilization (IVF) remains off-label, it has been used specifically for this purpose since at least 2007. Although most published reports on Essure placement before IVF have been reassuring, clinical experience remains limited, and no randomized studies have demonstrated the safety or efficacy of Essure in this context. In fact, no published guidelines deal with patient selection or counseling regarding the Essure procedure specifically in the context of IVF. Although Essure is an irreversible birth control option, some patients request the surgical removal of the implants for various reasons. While these patients could eventually undergo hysterectomy, at present no standardized technique exists for simple Essure removal with conservation of the uterus. This article emphasizes new aspects of the Essure procedure, as we describe the first known association between the placement of Essure implants and the subsequent development of fluid within the uterine cavity, which resolved after the surgical removal of both devices.