Intrauterine botulinum toxin A administration promotes endometrial regeneration mediated by IGFBP3-dependent OPN proteolytic cleavage in thin endometrium.

Adequate endometrial growth is a critical factor for successful embryo implantation and pregnancy maintenance. We previously reported the efficacy of intrauterine administration of botulinum toxin A (BoTA) in improving the endometrial angiogenesis and the rates of embryo implantation. Here, we further evaluated its potent therapeutic effects on the uterine structural and functional repair and elucidated underlying molecular regulatory mechanisms. This study demonstrated that a murine model of thin endometrium was successfully established by displaying dramatically decreased endometrial thickness and the rates of embryo implantation compared to normal endometrium. Interestingly, the expressions of insulin-like growth factor binding protein-3 (IGFBP3) and an active 35 kDa-form of osteopontin (OPN) were significantly reduced in thin endometrium, which were almost fully restored by intrauterine BoTA administration. Neutralization of BoTA-induced IGFBP3 subsequently suppressed proteolytic cleavage of OPN, exhibiting un-recovered endometrial thickness even in the presence of BoTA administration, suggesting that BoTA-induced endometrial regeneration might be mediated by IGFBP3-dependent OPN proteolytic cleavage. Our findings suggest that intrauterine BoTA administration improves the endometrial environment in our murine model with thin endometrium by increasing endometrial receptivity and angiogenesis in a manner dependent on the regulatory effect of IGFBP3 on OPN proteolytic cleavage, proposing BoTA as an efficient therapeutic strategy for the patients with thin endometrium.

Three-dimensional microengineered vascularised endometrium-on-a-chip.

STUDY QUESTION: Can we reconstitute physiologically relevant 3-dimensional (3D) microengineered endometrium in-vitro model? SUMMARY ANSWER: Our representative microengineered vascularised endometrium on-a-chip closely recapitulates the endometrial microenvironment that consists of three distinct layers including epithelial cells, stromal fibroblasts and endothelial cells in a 3D extracellular matrix in a spatiotemporal manner. WHAT IS KNOWN ALREADY: Organ-on-a-chip, a multi-channel 3D microfluidic cell culture system, is widely used to investigate physiologically relevant responses of organ systems. STUDY DESIGN, SIZE, DURATION: The device consists of five microchannels that are arrayed in parallel and partitioned by array of micropost. Two central channels are for 3D culture and morphogenesis of stromal fibroblast and endothelial cells. In addition, the outermost channel is for the culture of additional endometrial stromal fibroblasts that secrete biochemical cues to induce directional pro-angiogenic responses of endothelial cells. To seed endometrial epithelial cells, on Day 8, Ishikawa cells were introduced to one of the two medium channels to adhere on the gel surface. After that, the microengineered endometrium was cultured for an additional 5-6 days (total ∼ 14 days) for the purpose of each experiment. PARTICIPANTS/MATERIALS, SETTING, METHODS: Microfluidic 3D cultures were maintained in endothelial growth Medium 2 with or without oestradiol and progesterone. Some cultures additionally received exogenous pro-angiogenic factors. For the three distinct layers of microengineered endometrium-on-a-chip, the epithelium, stroma and blood vessel characteristics and drug response of each distinct layer in the microfluidic model were assessed morphologically and biochemically. The quantitative measurement of endometrial drug delivery was evaluated by the permeability coefficients. MAIN RESULTS AND THE ROLE OF CHANCE: We established microengineered vascularised endometrium-on-chip, which consists of three distinct layers: epithelium, stroma and blood vessels. Our endometrium model faithfully recapitulates in-vivo endometrial vasculo-angiogenesis and hormonal responses displaying key features of the proliferative and secretory phases of the menstrual cycle. Furthermore, the effect of the emergency contraception drug levonorgestrel was evaluated in our model demonstrating increased endometrial permeability and blood vessel regression in a dose-dependent manner. We finally provided a proof of concept of the multi-layered endometrium model for embryo implantation, which aids a better understanding of the molecular and cellular mechanisms underlying this process. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: This report is largely an in-vitro study and it would be beneficial to validate our findings using human primary endometrial cells. WIDER IMPLICATIONS OF THE FINDINGS: Our 3D microengineered vascularised endometrium-on-a-chip provides a new in-vitro approach to drug screening and drug discovery by mimicking the complicated behaviours of human endometrium. Thus, we suggest our model as a tool for addressing critical challenges and unsolved problems in female diseases, such as endometriosis, uterine cancer and female infertility, in a personalised manner. STUDY FUNDING/COMPETING INTEREST(S): This work is supported by funding from the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) to Y.J.K. (No. 2018R1C1B6003), to J.A. (No. 2020R1I1A1A01074136) and to H.S.K. (No. 2020R1C1C100787212). The authors report no conflicts of interest.

Medical Help-Seeking Strategies for Perinatal Women With Obstetric and Mental Health Problems and Changes in Medical Decision Making Based on Online Health Information: Path Analysis.

BACKGROUND: Previous studies have revealed that most pregnant women rarely discuss informal information found on the internet with health professionals and have frequently expressed concerns for medical experts' reactions to the online information they shared, as well as the lack of time to consult the medical experts in general. To date, little information is available on the effect of individual differences in utilizing medical help-seeking strategies on their medical decisions during the perinatal period. OBJECTIVE: The objectives of this study were (1) to determine associations among perinatal women's medical help-seeking strategies, changes in medical decision making, and online health information utilization with a focus on the mediating effect of self-efficacy in perinatal health literacy on the intent to consult health professionals, and (2) to clarify these associations in perinatal women with two different medical problems: obstetric and mental health. METHODS: A total of 164 perinatal women aged 24 to 47 years (mean 34.64, SD 3.80) repeatedly completed the Problem Solving in Medicine and Online Health Information Utilization questionnaires to examine the moderating effect of two types of medical problems on their decision-making processes. To validate the hypothesized relationships in the proposed conceptual model encompassing obstetric and mental health problem-solving models, path analyses were performed. RESULTS: This study found that some perinatal women, who use an online informal medical help-seeking (OIMH) strategy, would be more likely to change their medical decisions based only on internet-based information without consulting health professionals (P<.001), compared to other women using different medical help-seeking strategies. Particularly, this concern is significantly prevalent when encountering obstetric problems during the perinatal period (obstetric problem-solving: P<.001; mental health problem-solving: P=.02). Furthermore, perinatal women with mental health issues using the OIMH strategy showed a significant difference in intent to consult health professionals based on online health information when the medical problem they had to solve was different (obstetric problem-solving: P=.94; mental health problem-solving: P=.003). CONCLUSIONS: Despite the positive mediating effects of perinatal women's enhanced health literacy on the intent to discuss personal medical issues with health professionals based on online health information, the strategy used is of fundamental importance for understanding their help-seeking and decision-making processes during the perinatal period. Beyond a short consultation to steer patients quickly and authoritatively towards an obstetric doctor's choice of action, it is recommended in this study that obstetricians attempt to provide their patients with needed context for the information found online. To fully explain this information with an open mind, they should actively develop or support information and communications technology (ICT)-based health information services.

Serial Evaluation of Endometrial Blood Flow for Prediction of Pregnancy Outcomes in Patients Who Underwent Controlled Ovarian Hyperstimulation and In Vitro Fertilization and Embryo Transfer.

OBJECTIVES: To investigate endometrial blood flow during the menstrual cycle in patients undergoing controlled ovarian hyperstimulation (COH), in vitro fertilization (IVF), and embryo transfer (ET) and prediction of pregnancy outcomes based on these characteristics. METHODS: Endometrial blood flow was measured in 35 patients undergoing COH and IVF-ET (nonpregnant [n = 15] and pregnant [n = 20]) by measuring the resistive index (RI) of the uterine radial artery using 2-dimensional Doppler ultrasonography. Measurements were obtained in 4 different phases of the menstrual cycle day: early follicular, midfollicular, preovulatory, and midluteal. RESULTS: The uterine radial artery RI during the early follicular phase was significantly lower in the pregnant group than in the nonpregnant group (mean ± SD, 0.61 ± 0.01 versus 0.66 ± 0.01; P = .029). There was no significant difference between groups during the midfollicular, preovulatory, and midluteal phases (mean ± SD, 0.60 ± 0.02 versus 0.60 ± 0.01; P = .84; 0.61 ± 0.09 versus 0.57 ± 0.01; P = .12; 0.54 ± 0.01 versus 0.57 ± 0.02; P = .32, respectively). There was a significant difference in endometrial blood flow between the pregnant and nonpregnant groups during each phase (P = .016). The difference in the changes of the uterine radial artery RI from the preovulatory to midluteal phase between the pregnant and non pregnant groups was significant (-0.002 ± 0.03 versus 0.07 ± 0.02; P = .038). CONCLUSIONS: Increased endometrial blood flow during the midluteal phase, compared to the preovulatory phase, may correlate with successful COH and IVF-ET. Additionally, sufficient blood flow at initiation of COH may affect COH and IVF-ET results.

Clinical utility of newly developed highly purified human menopausal gonadotrophins: a randomized controlled trial.

The aim of this study was to evaluate the safety and efficacy of IVF-M HP, a newly developed highly purified human menopausal gonadotrophin preparation, for ovarian stimulation in women with infertility undergoing IVF, intracytoplasmic sperm injection (IVF-ICSI) and embryo transfer using a GnRH antagonist protocol. This was a multicentre, randomized, active-controlled, parallel design, open-label, non-inferiority clinical study. Of the 112 patients randomized for treatment using the GnRH antagonist protocol, 111 were treated. No significant difference was found in the number of oocytes retrieved from the IVF-M HP and Menopur groups (13.1 ± 7.6 versus 10.3 ± 6.7, respectively). The lower limit of the one-sided 97.5% confidence interval for the difference between the groups was -0.25, i.e., greater than the pre-defined non-inferiority margin (-5). Therefore, the IVF-M HP treatment was considered non-inferior to Menopur. Furthermore, no significant difference was observed between the groups in the number of good-quality oocytes, leading follicles, good-quality embryos, or in fertilization, implantation, positive beta-HCG and clinical pregnancy rates. The safety analysis revealed that 40.4% and 35.2% in the IVF-M HP and Menopur groups, respectively, reported adverse events. In conclusion, IVF-M HP had comparable clinical efficacy and safety profiles to Menopur.

The therapeutic effects of vitamin D3 administration on the embryo implantation.

Various adjuvants have been tested clinically for patients with problems with embryo implantation during in vitro fertilization (IVF)-embryo transfer (ET). Vitamin D3, an essential modulator of various physiological processes, has received attention as an important adjuvant for successful pregnancy, as many studies have shown a strong association between vitamin D deficiency and implantation failure and fetal growth restriction. However, vitamin D has been widely utilized in different protocols, resulting in non-reproducible and debatable outcomes. In the present study, we demonstrated that cyclic intrauterine administration of vitamin D3 increased endometrial receptivity and angiogenesis, which could be attributed to increased recruitment of uterus-resident natural killer cells. In particular, cyclic treatment of vitamin D3 promoted stable attachment of the embryo onto endometrial cells in vitro, suggesting its merit during the early stage of embryo implantation to support the initial maternal-fetal interactions. Our findings suggest that women with repeated implantation failure may benefit from the use of vitamin D3 as a risk-free adjuvant prior to IVF-ET procedures to improve the uterine environment, and make it favorable for embryo implantation.

Endometrial organoids: a reservoir of functional mitochondria for uterine repair.

Background: Asherman's syndrome (AS) is a dreadful gynecological disorder of the uterus characterized by intrauterine adhesion with severe fibrotic lesions, resulting in a damaged basalis layer with infertility. Despite extensive research on overcoming AS, evidence-based effective and reproducible treatments to improve the structural and functional morphology of the AS endometrium have not been established. Methods: Endometrial organoids generated from human or mouse endometrial tissues were transplanted into the uterine cavity of a murine model of AS to evaluate their transplantable feasibility to improve the AS uterine environment. The successful engraftment of organoid was confirmed by detection of human mitochondria and cytosol (for human endometrial organoid) or enhanced green fluorescent protein signals (for mouse endometrial organoid) in the recipient endometrium. The therapeutic effects mediated by organoid transplantation were examined by the measurements of fibrotic lesions, endometrial receptivity and angiogenesis, and fertility assessment by recording the number of implantation sites and weighing the fetuses and placenta. To explore the cellular and molecular mechanisms underlying the recovery of AS endometrium, we evaluated the status of mitochondrial movement and biogenetics in organoid transplanted endometrium. Results: Successfully engrafted endometrial organoids with similar morphological and molecular features to the parental tissues dramatically repaired the AS-induced damaged endometrium, significantly reducing fibrotic lesions and increasing fertility outcomes in mice. Moreover, dysfunctional mitochondria in damaged tissues, which we propose might be a key cellular feature of the AS endometrium, was fully recovered by functional mitochondria transferred from engrafted endometrial organoids. Endometrial organoid-originating mitochondria restored excessive collagen accumulation in fibrotic lesions and shifted uterine metabolic environment to levels observed in the normal endometrium. Conclusions: Our findings suggest that endometrial organoid-originating mitochondria might be key players to mediate uterine repair resulting in fertility enhancement by recovering abrogated metabolic circumstance of the endometrium with AS. Further studies addressing the clinical applicability of endometrial organoids may aid in identifying new therapeutic strategies for infertility in patients with AS.

The timing of adenomyosis diagnosis and its impact on pregnancy outcomes: a national population-based study.

OBJECTIVE: Adenomyosis impacts pregnancy outcomes, although there is a lack of consensus regarding the actual effects. It is likely, however, that the severity of adenomyosis or ultrasound findings or timing of diagnosis can have different effects on adverse pregnancy outcomes (APOs). METHODS: In this study, we aimed to investigate the impact of the timing of adenomyosis diagnosis on pregnancy outcomes. Singleton pregnant women who delivered between 2017 and 2022 were analyzed based on the timing of adenomyosis diagnosis, using a national database. The final cohort was classified into three groups: 1) group 1, without adenomyosis; 2) group 2, those diagnosed with adenomyosis before pregnancy; and 3) group 3, those diagnosed with adenomyosis during pregnancy. RESULTS: A total of 1,226,475 cases were ultimately included in this study. Women with a diagnosis of adenomyosis had a significantly higher risk of APOs including hypertensive disorder during pregnancy (HDP), gestational diabetes mellitus (GDM), postpartum hemorrhage, placental abruption, preterm birth, and delivery of a small-for-gestational-age infant even after adjusting for covariates. In particular, concerning HDP, the risk was highest in group 3 (group 2: adjusted odds ratio [aOR], 1.15 vs. group 3: aOR, 1.36). However, the highest GDM risk was in group 2 (GDM; group 2: aOR, 1.24 vs. group 3: aOR, 1.04). CONCLUSION: The increased risk of APO differed depending on the timing of adenomyosis diagnosis. Therefore, efforts for more careful monitoring and prevention of APOs may be necessary when such women become pregnant.

Accumulated Vitrified Embryos Could Be a Method for Increasing Pregnancy Rates in Patients with Poor Ovarian Response.

We aimed to assess the efficacy of accumulated embryo transfer (ACC-ET) through several controlled ovarian hyperstimulation (COS) cycles to increase the rates of pregnancy in patients with poor ovarian response (POR). We retrospectively reviewed the medical records of 588 patients with POR under 43-years old who underwent embryo transfer from January 2010 to December 2015. We compared the pregnancy rate (PR), clinical pregnancy rate (CPR), and live birth rate (LBR) between ACC-ET (frozen-thawed: 47; fresh + frozen-thawed: 24) group (n = 71) and fresh ET groups (n = 517). Characteristics of ACC-ET patients were similar to those of fresh ET groups (Age: 38.1 ± 3.5 vs. 38.2 ± 3.7, p = 0.88; Anti Müllerian Hormone (AMH; ng/mL): 0.5 ± 0.4 vs. 0.6 ± 0.6, p = 0.38; follicle stimulating hormone (FSH: mIU/mL): 11.9 ± 8.0 vs. 10.8 ± 9.0, p = 0.35). The total number of transferred embryos (3.1 ± 0.9 vs. 1.5 ± 0.7, p = 0.00), PR (29.6% (21/71) vs. 18.8% (97/517), p = 0.040), and CPR (23.5% (16/68) vs. 14.0% (71/508) p = 0.047) were significantly higher in the ACC-ET group than in the fresh ET group. In addition, PR, CPR, and LBR increased with the number of ET in the fresh ET group. However, there were no significant differences observed in LBR between ACC-ET and fresh ET groups (14.9% (10/67) vs. 9.8% (50/508), p = 0.203). From our knowledge, there is no clinical evidence reported to prove that transfer of multiple embryos of adequate quality obtained through multiple cycles can compensate for the limited number of retrieved oocytes from POR patients. We concluded that ACC-ET from several COS cycles could be an alternative method to increase PR and CPR in <43-year-old patients with POR.

Non-invasive Intrauterine Administration of Botulinum Toxin A Enhances Endometrial Angiogenesis and Improves the Rates of Embryo Implantation.

Endometrial angiogenesis plays crucial roles in determining the endometrial receptivity. Defects in endometrial receptivity often cause repeated implantation failure, which is one of the major unmet needs for infertility and contributes a major barrier to the assisted reproductive technology. Despite the numerous extensive research work, there are currently no effective evidence-based treatments to prevent or cure this condition. As a non-invasive treatment strategy, botulinum toxin A (BoTA) was administered into one side of mouse uterine horns, and saline was infused into the other side of horns for the control. Impact of BoTA was assessed in the endometrium at 3 or 8 days after infusion. We demonstrated that BoTA administration enhances the capacity of endothelial cell tube formation and sprouting. The intrauterine BoTA administration significantly induced endometrial angiogenesis displaying increased numbers of vessel formation and expression levels of related marker genes. Moreover, BoTA intrauterine application promoted the endometrial receptivity, and the rates of embryo implantation were improved with BoTA treatment with no morphologically retarded embryos. Intrauterine BoTA treatment has a beneficial effect on vascular reconstruction of functional endometrium prior to embryo implantation by increasing endometrial blood flow near the uterine cavity suggesting BoTA treatment as a potential therapeutic strategy for patients who are suffering from repeated implantation failure with the problems with endometrial receptivity.

Dysfunctional activity of classical DNA end-joining renders acquired resistance to carboplatin in human ovarian cancer cells.

Ovarian cancer is the deadliest gynecological malignancy worldwide. Although chemotherapy is required as the most standard treatment strategy for ovarian cancer, the survival rates are very low, largely because of high incidence of recurrence due to resistance to conventional surgery and genotoxic chemotherapies. Carboplatin-resistant ovarian cancer cells were generated by continuous treatment over six months. Carboplatin-resistance induced morphological alterations and promoted the rates of proliferation and migration of SKOV3 compared to the parental cells. Interestingly, carboplatin-resistant SKOV3 showed the high levels of γH2AX foci formed at the basal level, and the levels of γH2AX foci remained even after the recovery time, suggesting that the DNA damage response and repair machinery were severely attenuated by carboplatin-resistance. Surprisingly, the expression levels of XRCC4, a critical factor in non-homologous end joining (NHEJ) DNA repair, were significantly decreased in carboplatin-resistant SKOV3 compared with those in non-resistant controls. Furthermore, restoration of NHEJ in carboplatin-resistant SKOV3 by suppression of ABCB1 and/or AR re-sensitized carboplatin-resistant cells to genotoxic stress and reduced their proliferation ability. Our findings suggest that attenuation of the NHEJ DNA repair machinery mediated by resistance to genotoxic stress might be a critical cause of chemoresistance in patients with ovarian cancer.

CXCL12 enhances pregnancy outcome via improvement of endometrial receptivity in mice.

Successful pregnancy inevitably depends on the implantation of a competent embryo into a receptive endometrium. Although many substances have been suggested to improve the rate of embryo implantation targeting enhancement of endometrial receptivity, currently there rarely are effective evidence-based treatments to prevent or cure this condition. Here we strongly suggest minimally-invasive intra-uterine administration of embryo-secreted chemokine CXCL12 as an effective therapeutic intervention. Chemokine CXCL12 derived from pre- and peri-implanting embryos significantly enhances the rates of embryo attachment and promoted endothelial vessel formation and sprouting in vitro. Consistently, intra-uterine CXCL12 administration in C57BL/6 mice improved endometrial receptivity showing increased integrin ß3 and its ligand osteopontin, and induced endometrial angiogenesis displaying increased numbers of vessel formation near the lining of endometrial epithelial layer with higher CD31 and CD34 expression. Furthermore, intra-uterine CXCL12 application dramatically promoted the rates of embryo implantation with no morphologically retarded embryos. Thus, our present study provides a novel evidence that improved uterine endometrial receptivity and enhanced angiogenesis induced by embryo-derived chemokine CXCL12 may aid to develop a minimally-invasive therapeutic strategy for clinical treatment or supplement for the patients with repeated implantation failure with less risk.

Eupatilin treatment inhibits transforming growth factor beta-induced endometrial fibrosis in vitro.

OBJECTIVE: Endometrial fibrosis, the primary pathological feature of intrauterine adhesion, may lead to disruption of endometrial tissue structure, menstrual abnormalities, infertility, and recurrent pregnancy loss. At present, no ideal therapeutic strategy exists for this fibrotic disease. Eupatilin, a major pharmacologically active flavone from Artemisia, has been previously reported to act as a potent inducer of dedifferentiation of fibrotic tissue in the liver and lung. However, the effects of eupatilin on endometrial fibrosis have not yet been investigated. In this study, we present the first report on the impact of eupatilin treatment on transforming growth factor beta (TGF-ß)-induced endometrial fibrosis. METHODS: The efficacy of eupatilin on TGF-ß-induced endometrial fibrosis was assessed by examining changes in morphology and the expression levels of fibrosis markers using immunofluorescence staining and quantitative real-time reverse-transcription polymerase chain reaction. RESULTS: Eupatilin treatment significantly reduced the fibrotic activity of TGF-ß-induced endometrial fibrosis in Ishikawa cells, which displayed more circular shapes and formed more colonies. Additionally, the effects of eupatilin on fibrotic markers including alpha-smooth muscle actin, hypoxia-inducible factor 1 alpha, collagen type I alpha 1 chain, and matrix metalloproteinase-2, were evaluated in TGF-ß-induced endometrial fibrosis. The expression of these markers was highly upregulated by TGF-ß pretreatment and recovered to the levels of control cells in response to eupatilin treatment. CONCLUSION: Our findings suggest that suppression of TGF-ß-induced signaling by eupatilin might be an effective therapeutic strategy for the treatment of endometrial fibrosis.

Endometrial profilin 1: a key player in embryo-endometrial crosstalk.

OBJECTIVE: Despite extensive research on implantation failure, little is known about the molecular mechanisms underlying the crosstalk between the embryo and the maternal endometrium, which is critical for successful pregnancy. Profilin 1 (PFN1), which is expressed both in the embryo and in the endometrial epithelium, acts as a potent regulator of actin polymerization and the cytoskeletal network. In this study, we identified the specific role of endometrial PFN1 during embryo implantation. METHODS: Morphological alterations depending on the status of PFN1 expression were assessed in PFN1-depleted or control cells grown on Matrigel-coated cover glass. Day-5 mouse embryos were cocultured with Ishikawa cells. Comparisons of the rates of F-actin formation and embryo attachment were performed by measuring the stability of the attached embryo onto PFN1-depleted or control cells. RESULTS: Depletion of PFN1 in endometrial epithelial cells induced a significant reduction in cell-cell adhesion displaying less formation of colonies and a more circular cell shape. Mouse embryos co-cultured with PFN1-depleted cells failed to form actin cytoskeletal networks, whereas more F-actin formation in the direction of surrounding PFN1-intact endometrial epithelial cells was detected. Furthermore, significantly lower embryo attachment stability was observed in PFN1-depleted cells than in control cells. This may have been due to reduced endometrial receptivity caused by impaired actin cytoskeletal networks associated with PFN1 deficiency. CONCLUSION: These observations definitively demonstrate an important role of PFN1 in mediating cell-cell adhesion during the initial stage of embryo implantation and suggest a potential therapeutic target or novel biomarker for patients suffering from implantation failure.

Effect of Autologous Platelet-Rich Plasma Treatment on Refractory Thin Endometrium During the Frozen Embryo Transfer Cycle: A Pilot Study.

Objective: Thin or damaged endometrium remains to be an unsolved problem in the treatment of patients with infertility. The empirical preference for endometrial thickness (EMT) among clinicians is >7 mm, and the refractory thin endometrium, which doesn't respond to standard medical therapies, can be the etiology of recurrent implantation failure (RIF). Autologous platelet-rich plasma (PRP) is known to help tissue regeneration and is widely used in various fields. In the present study, we conducted PRP treatment and investigated its effect on the refractory thin endometrium. Design: Prospective interventional study (https://cris.nih.go.kr/cris, clinical trial registration number: KCT0003375). Methods: Women who had a history of two or more failed IVF cycles and refractory thin endometrium were enrolled in this study. The main inclusion criteria were EMT of <7 mm after more than 2 cycles of previous medical therapy for increasing the EMT. Twenty-four women were enrolled in this study. The subjects were treated with intrauterine infusion of autologous PRP 2 or 3 times from menstrual cycle day 10 of their frozen-thawed embryo transfer (FET) cycle, and ET was performed 3 days after the final autologous PRP infusion. 22 patients underwent FET, and 2 patients were lost to follow up. Results: The ongoing pregnancy rate and LBR were both 20%. The implantation and clinical pregnancy rates were 12.7 and 30%, respectively, and the difference was statistically significant. The average increase in the EMT was 0.6 mm compared with the EMT of their previous cycle. However, this difference was not statistically significant. Further, EMT of 12 patients increased (mean difference: 1.3 mm), while that of seven patients decreased (mean difference: 0.7 mm); the EMT of one patient did not change. There were no adverse effects reported by the patients who were treated with autologous PRP. Conclusions: The use of autologous PRP improved the implantation, pregnancy, and live birth rates (LBR) of the patients with refractory thin endometrium. We assume that the ability of autologous PRP to restore the endometrial receptivity of damaged endometrium has some aspects other than increasing the EMT. The molecular basis of the treatment needs to be revealed in future studies.

The likelihood of achieving pregnancy through timed coitus in young infertile women with decreased ovarian reserve.

OBJECTIVE: To evaluate the pregnancy rate and time to pregnancy after timed coitus with or without superovulation in infertile young women younger than 35 years old with low serum anti-Müllerian hormone (AMH) levels (<25th percentile). METHODS: A total of 202 patients younger than 35 years old were recruited retrospectively between 2010 and 2012. Ninety-eight women had normal serum AMH levels (25-75th percentile), 75 women had low serum AMH levels (5th≤&<25th percentile) and 29 women had very low serum AMH levels (<5th percentile), according to reference values for their age group. RESULTS: The clinical pregnancy rate was positively associated with AMH levels, but this trend did not reach statistical significance (43.9% vs. 41.3% vs. 27.6% in the normal, low, and very low AMH groups, respectively). The time to pregnancy was longer in the very low AMH group than in the normal AMH group (13.1±10.9 months vs. 6.9±6.1 months, p=0.030). The cumulative live birth rate over 18 months was lower in the very low AMH group than in the normal AMH group, with marginal significance (20.0% vs. 55.9%, p=0.051). The duration of infertility was negatively correlated with achieving pregnancy (odds ratio, 0.953; 95% confidence interval, 0.914-0.994; p=0.026). CONCLUSION: Conservative management, such as timed coitus with or without superovulation, should be considered in young patients who have low ovarian reserve without any infertility factors. However, for women with a long duration of infertility or very low serum AMH levels, active infertility treatment should be considered.

Reproductive outcomes of retransferring retained embryos in blastocyst transfer cycles.

OBJECTIVE: To determine the incidence of embryo retention (ER) in the transfer catheter following embryo transfer (ET) in blastocyst transfer and investigate whether retransferring retained embryos has an impact on reproductive outcomes in patients undergoing in vitro fertilization-ET. METHODS: We retrospectively analyzed the records of 1,131 blastocyst transfers, which comprised 223 single blastocyst transfer (SBT) and 908 double blastocyst transfer (DBT) cycles. Each SBT and DBT group was classified depending on whether ET was performed without retained embryos in the catheter during the first attempt (without-ER group) or whether any retained embryos were found following ET (ER group) for the purpose of comparing reproductive outcomes in a homogenous population. RESULTS: The overall incidence of finding retained embryos was 2.8% (32/1,131). There were no retained embryos in SBT cycles. In DBT cycles, implantation rates (30.0% vs. 26.6%), positive ß-hCG rates (57.2% vs. 56.2%), clinical pregnancy rates (45.3% vs. 46.9%), and live birth rates (38.9% vs. 43.8%) were not significantly different between the without-ER and ER groups. There were no significant differences in the mean birth weight (g) 2,928.4±631.8 vs. 2,948.7±497.8 and the mean gestational age at birth (269.3±17.2 days vs. 264.2±25.7 days). A total of nine cases of congenital birth defects were found in this study population. Eight were observed in the without-ER group and one in the ER group. CONCLUSION: Our results suggest that retransfer of retained embryos does not have any adverse impact on reproductive outcomes in blastocyst transfer cycles. Furthermore, our results support finding that SBT might be advantageous for decreasing the incidence of retained embryos in catheters.

A high response to controlled ovarian stimulation induces premature luteinization with a negative impact on pregnancy outcomes in a gonadotropin-releasing hormone antagonist cycle.

OBJECTIVE: The goal of this study was to investigate the relationship between serum progesterone (P4) levels on the day of human chorionic gonadotropin (hCG) administration and the pregnancy rate among women undergoing controlled ovarian stimulation for in vitro fertilization (IVF) or intracytoplasmic sperm injection-embryo transfer (ICSI-ET) using a flexible antagonist protocol. METHODS: This prospective study included 200 IVF and ICSI-ET cycles in which a flexible antagonist protocol was used. The patients were divided into five distinct groups according to their serum P4 levels at the time of hCG administration (0.80, 0.85, 0.90, 0.95, and 1.00 ng/mL). The clinical pregnancy rate (CPR) was calculated for each P4 interval. Statistically significant differences were observed at a serum P4 level of 0.9 ng/mL. These data suggest that a serum P4 concentration of 0.9 ng/mL may represent the optimal threshold level for defining premature luteinization (PL) based on the presence of a significant negative impact on the CPR. RESULTS: The CPR for each round of ET was significantly lower in the PL group defined using this threshold (25.8% vs. 41.8%; p=0.019), and the number of oocytes retrieved was significantly higher than in the non-PL group (17.3±7.2 vs. 11.0±7.2; p=0.001). Elevated serum P4 levels on the day of hCG administration were associated with a reduced CPR, despite the retrieval of many oocytes. CONCLUSION: Measuring serum P4 values at the time of hCG administration is necessary in order to determine the optimal strategy for embryo transfer.

Resistance of uterine radial artery blood flow was correlated with peripheral blood NK cell fraction and improved with low molecular weight heparin therapy in women with unexplained recurrent pregnancy loss.

PROBLEM: To investigate whether peripheral blood natural killer (pbNK) cell levels are associated with uterine blood flow, and low molecular weight heparin (LMWH) treatment is effective to improve uterine blood flow in women with decreased uterine blood flow and unexplained recurrent pregnancy loss (RPL). METHOD OF STUDY: This was a prospective controlled study. Study population included 33 pregnant women (between 5 and 7 weeks gestation) with ≥ 2 RPL and controls were 47 healthy pregnant women. pbNK cell fractions (CD3(-)/56(+)/16(+)) of peripheral blood mononuclear cells were measured by flow cytometry. Uterine color-pulsed Doppler ultrasound was performed to evaluate uterine radial artery resistance index (URa-RI). In RPL women with elevated URa-RI (≥ 0.5), LMWH (ranges 40-60 mg/day) was administered subcutaneously daily and URa-RI was reassessed 1 week later. Pregnancy outcome was analyzed at 12 weeks gestation. RESULTS: URa-RI was significantly higher in pregnant women with RPL than controls (0.60 ± 0.14 versus 0.54 ± 0.12, P = 0.039). In pregnant women with RPL, pbNK cell fractions displayed a positive correlation with URa-RI (Pearson's r = 0.429, P = 0.013). URa-RI was significantly decreased 1 week after LMWH treatment as compared to that of pretreatment (pretreatment RI: 0.65 ± 0.11 versus post-treatment RI: 0.56 ± 0.13, P = 0.011). Pregnancy outcome of RPL women with LMWH treatment was not different from that of pregnant controls (73.3% versus 85.0%, P = NS). CONCLUSION: Increased pbNK cells are associated with decreased uterine radial artery blood flow. LMWH treatment effectively decreases URa-RI with improved pregnancy outcome in women with RPLs and elevated URa-RI. A larger scale study is needed to verify these findings.

Elevated natural killer cell levels and autoimmunity synergistically decrease uterine blood flow during early pregnancy.

OBJECTIVE: To investigate whether natural killer (NK) cell and autoimmune antibody acts synergistically, by the action of autoantibodies to increase NK cell number and cytotoxicity, to decrease uterine blood flow during early pregnancy in pregnant women with a history of recurrent spontaneous abortion (RSA). METHODS: Seventy-five pregnant women (between 5 and 7 weeks gestation) with a history of unexplained RSA were included in the study group. Forty-one pregnant women without a history of RSA were included as controls. All women with a history of RSA were tested for autoantibodies and number of peripheral blood natural killer (pbNK) cell by flow cytometry. Study populations were stratified into four groups by existence of autoantibody and degree of increase of pbNK cells. The uterine radial artery resistance index (RI) was measured by color-pulsed Doppler transvaginal ultrasound. RESULTS: The mean RI of the autoimmune antibody-positive (AA+) group (0.63±0.09) was significantly higher than that of the normal control group (0.53±0.10, P=0.001). The mean RI of the AA+/only-NK elevated (eNK) group (0.63±0.09) was significantly higher than those of the only-AA+ group (0.55±0.07, P=0.019) and the only-eNK group (0.57±0.07, P=0.021). CONCLUSION: Concurrent elevation in NK cells and autoimmunity results in decreased uterine blood flow during early pregnancy. However, the majority of cases of RSA remain unexplained and larger scale studies are needed to confirm our conclusion and to develop diagnostic and therapeutic plans for women with a history of RSA.