Embryo location in the uterus during embryo transfer: An in vitro simulation.
ABSTRACT: OBJECTIVE:To evaluate the location of transferred embryos under various parameters during embryo transfer in in vitro fertilization (IVF) by applying an in vitro experimental model for embryo transfer (ET). METHODS:Mock ET simulations were conducted with a laboratory model of the uterine cavity. The transfer catheter was loaded with a sequence of air and liquid volumes, including development-arrested embryos donated by patients. The transfer procedure was recorded using a digital video camera. An orthogonal design, including three independent variables (uterine orientation, distance of the catheter tip to the fundus, and injection speed) and one dependent variable (final embryo position), was applied. RESULTS:The uterine cavity was divided into six regions. The distribution of the transferred matter within the uterine cavity varied according to the uterine orientation. Medium speed-injected embryos were mostly found in the static region while fast- and slow-speed injected embryos were mostly found in the fundal region and the cervical-left region, respectively. The possibility of embryo separation from the air bubble increased from 11.1% in slow injection cases to 29.6% and 48.1% in medium and fast injection cases, respectively. CONCLUSION:The experimental model provides a new method for investigating ET procedures. Fast injection of embryos into a retroverted uterus may be more likely to result in embryo separation from the air bubble.
Project description:The normal intrauterine fluid environment is essential for embryo implantation. In hydrosalpinx patients, the implantation and pregnancy rates are markedly decreased after IVF-embryo transfer, while salpingectomy could significantly improve the pregnancy rates. The leakage of hydrosalpinx fluid into the endometrial cavity was supposed to be the major cause for impaired fertility. However, the underlying mechanisms of hydrosalpinx fluids on implantation and ongoing pregnancy were not fully understood and remain controversial regarding its toxicity. In present study, by infusing different volume of non-toxic fluid (0.9% saline) into uterine lumen before embryo implantation in mice (Day4 08:30), we found that while the embryos were not "flushed out" from the uteri, the timing of implantation was deferred and normal intrauterine distribution (embryo spacing) was disrupted. The abnormal implantation at early pregnancy further lead to embryo growth retardation, miscarriage and increased pregnancy loss, which is similar to the adverse effects observed in hydrosalpinx patients undergoing IVF-ET. We further examined uterine receptivity related gene expression reported to be involved in human hydrosalpinx (Lif, Hoxa10, Integrin ?(v) and ?(3)). The results showed that expression of integrin ?(v) and ?(3) were increased in the fluid infused mouse uteri, implicating a compensatory effect to cope with the excessive fluid environment. Our data suggested that the adverse effects of excessive non-toxic luminal fluid on pregnancy are primarily due to the mechanical interference for normal timing and location of embryo apposition, which might be the major cause of decreased implantation rate in IVF-ET patients with hydrosalpinx.
Project description:BACKGROUND:With improvements in in vitro culture techniques there has been a steady shift in practice to transfer embryos at the blastocyst stage (post fertilization day (p.f.d.) 5-7), when embryos reach the endometrial cavity during natural conception. For patients with >?5 zygotes on day 1 of embryo development, fresh blastocyst embryo transfer (ET) increases live birth rates when compared to cleavage stage (p.f.d. 3) transfer. In poorer prognosis patients (? 5 zygotes) cleavage stage ET is commonly performed to reduce the risk of cycle cancellation if no embryo survives to the blastocyst stage. However, there is a dearth of randomized controlled trial (RCT) data demonstrating improved live birth rates per cycle for cleavage vs blastocyst stage ET in this subgroup of patients. The hypothesis of the PRECiSE (PooR Embryo Yield Cleavage Stage Versus blaStocyst Embryo Transfer) trial is that blastocyst ET is not inferior to cleavage stage ET with regard to live birth rates per retrieval in poorer prognosis patients. The adoption of routine blastocyst culture for all patients would result in higher rates of single embryo transfers (SET), reduced incidence of multiple pregnancies and simplified laboratory protocols, thereby reducing costs. METHODS/DESIGN:Multicenter, non-inferiority randomized controlled trial (RCT) comparing blastocyst to cleavage stage embryo transfer in poorer prognosis patients with ?5 zygotes on day 1 after fertilization. The primary outcome is live birth per retrieval. Secondary outcomes include: time to pregnancy, clinical pregnancy, ongoing pregnancy, miscarriage and multiple pregnancy rate (per retrieval). This trial will enroll 658 women with ?5 zygotes on day 1 at 6 IVF centers over the course of 22?months. DISCUSSION:If the hypothesis is proven true, the data from this trial may facilitate the adoption of uniform blastocyst culture in all IVF patients. TRIAL REGISTRATION:ClinicalTrials.gov Identifier: NCT03764865. Registered 5 December 2019, Protocol issue date: 4 December 2018, Original.
Project description:Receptivity is a limited time in which uterine endometrium can establish a successful dialogue with blastocyst. This study was to investigate the effect of asynchronous embryo transfer on uterine receptivity in mice. Embryos under different stages were transferred into two oviduct sides of a recipient mouse on day 1 of pseudopregnancy. Our results showed the asynchronously transferred embryos can implant in all groups. Compared to zygote-transfer group, the length of implanted embryos is longer in 8-cell embryo- or blastocyst-transfer group. The levels of Snail and COX-2 immunostaining in blastocyst-transfer group are significantly stronger than that in zygote-transfer group. Embryos in blastocyst-transfer group migrate faster than that in zygote-transfer group within uterus. Blastocysts are in a state of developmental delay after they are transferred into oviducts, and they are reactivated and implanted rapidly in uterus. The developmental rate to newborn in zygote-transfer group is obviously higher than that in blastocyst-transfer group, suggesting that a delay in embryo development and implantation will lead to a decrease of litter size. These results indicated that the window of implantation is differentially regulated in two uterine horns of a recipient by embryos at different stages.
Project description:STUDY QUESTION:Is Ongoing Pregnancy Rate (OPR) operator-dependent, and can experience improve embryo transfer efficiency? SUMMARY ANSWER:OPR is influenced by the operators who perform the embryo transfer (ET), and experience does not assure proficiency for everyone. WHAT IS KNOWN ALREADY:ET remains the critical step in assisted reproduction. Although many other factors such as embryo quality and uterine receptivity impact embryo implantation, the proper ET technique is clearly an operator-dependent variable and as such it should be objectively standardized. STUDY DESIGN, SIZE, DURATION:Retrospective comparative analysis including all fresh ETs performed between January 1996 and December 2016 at the Humanitas Fertility Center after IVF-ICSI cycles. PARTICIPANTS/MATERIALS, SETTING, METHODS:IVF/ICSI fresh ETs performed by 32 operators, 19?824 cycles in all, were analyzed. All transfers consisting of freehand insertion of a preloaded soft catheter into the uterine cavity under transabdominal ultrasound guidance were considered. Two different statistical analyses were performed. First, a logistic regression model with a random intercept for the operator was used to estimate the heterogeneity of the rate of success among operators, accounting for woman age, FSH, number of oocytes retrieved, fertilization rate, year of the procedure, number and stage of transferred embryos and operator's experience. Second, the relationship between experience and pregnancy rate was estimated separately for each operator by logistic regression, and operator-specific results were combined and compared in a random-effects meta-analysis. In both analyses, the operator's experience at time t was measured in terms of number of embryo transfers performed before t. MAIN RESULTS AND THE ROLE OF CHANCE:The heterogeneity among operators was highly significant (P value <0.001) and explained 44.5% of the total variability. The odds ratio of success of the worst operator in respect to the mean was equal to 0.84. For the best operator, the odds ratio of success was equal to 1.13 in respect to the mean. Based on the meta-analysis of the relationship between operator's experience and success rate, it resulted that, on average, the operators' performance did not improve with additional transfers. LIMITATIONS, REASONS FOR CAUTION:At our center, operators become independent for ET's after performing between 30 and 50 transfers under supervision. It is also possible that other relevant factors, such as embryologists on duty for the ET, have not been included in the present analysis and this may represent a potential bias. Among these, it should be mentioned that the embryologists on duty for the ET were not taken into consideration. WIDER IMPLICATIONS OF THE FINDINGS:Continued performance analysis and the use of a digital simulator could help operators to test their expertise over time and either correct poor performance or avoid doing transfers. STUDY FUNDING/COMPETING INTEREST(S):None. TRIAL REGISTRATION NUMBER:NCT03561129.
Project description:Background:Implantation failure limits the success of in vitro fertilization and embryo transfer (IVF-ET). Well-organized embryo-maternal crosstalk is essential for successful implantation. Previous studies mainly focused on the aberrant development of in vitro fertilized (IVF) embryos. In contrast, the mechanism of IVF-induced aberrant embryo-maternal crosstalk is not well defined. Results:In the present study, using ewes as the model, we profiled the proteome that features aberrant IVF embryo-maternal crosstalk following IVF-ET. By comparing in vivo (IVO) and IVF conceptuses, as well as matched endometrial caruncular (C) and intercaruncular (IC) areas, we filtered out 207, 295, and 403 differentially expressed proteins (DEPs) in each comparison. Proteome functional analysis showed that the IVF conceptuses were characterized by the increased abundance of energy metabolism and proliferation-related proteins, and the decreased abundance of methyl metabolism-related proteins. In addition, IVF endometrial C areas showed the decreased abundance of endometrial remodeling and redox homeostasis-related proteins; while IC areas displayed the aberrant abundance of protein homeostasis and extracellular matrix (ECM) interaction-related proteins. Based on these observations, we propose a model depicting the disrupted embryo-maternal crosstalk following IVF-ET: Aberrant energy metabolism and redox homeostasis of IVF embryos, might lead to an aberrant endometrial response to conceptus-derived pregnancy signals, thus impairing maternal receptivity. In turn, the suboptimal uterine environment might stimulate a compensation effect of the IVF conceptuses, which was revealed as enhanced energy metabolism and over-proliferation. Conclusion:Systematic proteomic profiling provides insights to understand the mechanisms that underlie the aberrant IVF embryo-maternal crosstalk. This might be helpful to develop practical strategies to prevent implantation failure following IVF-ET.
Project description:The air bubble entrainment and self-aeration phenomena in free-surface water flows reveal a rich interplay of fundamental science and engineering, and the size distribution of the entrained bubbles enhances the air-water gas flux, improves the gas transfer, and influences the cavitation erosion protection in high-speed flows. In the present study, we investigate the bubble-formation mechanism of free-surface air entrainment and the related microscopic bubble scale in the laboratory. This paper provides a quantitative description of bubble entrainment. The entrapment deformation of the local free surface over a period follows a power-law scaling and entrains a bubble when the entrapped surface becomes enclosed in the unstable movement period. Both the size scale and shape character of the entrapped free surface determine the size and skewness of the distribution of the air bubble. The entrapment deformation process confirms that the instability behaviour of the local air-water interface results in the onset of bubble entrainment. Further research is necessary to elucidate the instability criterion dominated by the interface instability and promote a new understanding of multiphase flow generation and development.
Project description:Purpose:To demonstrate the use of an air bubble in infusion to ascertain infusion tip (IT) positioning before commencing vitreoretinal surgery (VRS) in eyes with media opacities. Methods:Twenty-four eyes were studied. An air bubble was introduced into the IT by manually expelling fluid from the distal end of the IT. Passage of this air bubble into the vitreous cavity immediately on opening the infusion line confirmed IT position and VRS was commenced only after this event. Results:The air bubble was seen within the eye in 18/24 eyes immediately on opening the infusion line. In 6 eyes, the air bubble did not exit the infusion line, and VRS was commenced only after IT position was confirmed by other methods. In all 24 eyes, no untoward effect attributable to the air bubble was noticed during subsequent VRS. Conclusions:An air bubble introduced into the IT helps to quickly confirm IT position when direct visualization of the IT is difficult. There were no untoward events in eyes where the air bubble could not enter the vitreous cavity.
Project description:OBJECTIVE:To evaluate if an elevated progesterone (P) level on the day of human chorionic gonadotropin (hCG) administration is associated with a decrease in live-birth rate in patients with a good prognosis. DESIGN:Retrospective cohort study. SETTING:Large, private, assisted reproductive technology (ART) practice. PATIENT(S):One thousand six hundred twenty fresh autologous ART cycles. INTERVENTION(S):None. MAIN OUTCOME MEASURE(S):Live-birth rate. RESULT(S):A total of 934 blastocyst and 686 cleavage-stage embryo transfer (ET) cycles were evaluated. Serum P levels were not associated with markers of oocyte or embryo quality, including fertilization, embryo stage at transfer, and embryos available for cryopreservation. Patient age, stage of ET, embryo quality, the number of embryos transferred, and P level on the day of hCG administration were all significantly associated with live birth. Higher P levels were associated with decreased odds of live birth for cleavage- and blastocyst-stage embryos, poor-fair and good-quality embryos, and poor- and high-responder patients. The nonsignificance of interaction tests of P levels with embryo stage, embryo quality, patient age, and ovarian response indicated that the relationship between P level and live birth was similar regardless of these factors. CONCLUSION(S):An elevated serum P level on the day of hCG administration was negatively associated with live birth, even in ETs with a good prognosis.
Project description:The aim of this study is to compare implantation and live birth rates (LBR) between fresh euploid embryo transfers versus cryo-all cycles with a subsequent embryo transfer into a prepared endometrium.This is a retrospective cohort study. Patients who underwent an IVF cycle with PGS with trophectoderm biopsy from January 2011 to July 2015 were included. Patients were divided into three groups: "Fresh Only," "Frozen Embryo Transfer ('FET) Only," and "Fresh ET then FET." For "Fresh Only" group (n = 345), PGS results were received within 24 h. For "FET Only" group (n = 514), results were expected after 24 h, and embryos were cryopreserved after biopsy; only FET was performed in this group (no fresh transfer). For "FET with a previous fresh ET" (n = 139) group, patients underwent a fresh ET with a subsequent FET, in which the same cohort of embryos was utilized. The main outcome measures were pregnancy rate (PR), clinical PR, implantation rate (IR), LBR, and early pregnancy loss rate.IRs were statistically higher in the "FET Only" group when compared to the "Fresh Only" group (59.5 vs. 50.6%, p < 0.01) and the "FET with a previous fresh ET" (59.5 vs. 50.6%, p < 0.05). LBR was statistically significant in the "FET Only" group when compared to the "Fresh Only" group (57.6 vs. 46.5 %, p < 0.005) but not when compared to "FET with a previous fresh ET" group (57.6 vs. 47.7%, p = 0.07).This analysis suggests euploid embryos to be more likely to implant and achieve a LBR in a synthetic FET cycle than in a fresh cycle.
Project description:This study was designed to report the status of assisted reproductive technology (ART) therapy in South Korea between January 1, 2012 and December 31, 2012.A localized online survey, originally developed by the International Committee Monitoring Assisted Reproductive Technologies, was first launched and provided to all available ART centers via email in 2015. Fresh embryo transfer (FET) cases were categorized as standard in vitro fertilization, intracytoplasmic sperm injection (ICSI), or half-ICSI. Thawed embryo transfer (TET) and other related procedures, including surgical sperm retrieval, were surveyed.Data from 33,956 ovum pick-up procedures were provided by 75 clinics in 2012. Of the 33,088 cycles in which ovums were retrieved, a complete transfer was performed in 90.5% (29,932 cycles). In addition, 10,079 FET cycles were confirmed to have resulted in clinical pregnancy, representing a pregnancy rate of 30.5% per ovum pick-up and 33.7% per ET. The most common number of embryos transferred in FET was 2 (41.6%), followed by 3 (34.0%), and non-elective single ETs (10.0%). Of the 10,404 TET cycles in which transfer was completed, 3,760 clinical pregnancies (36.1%) were confirmed by ultrasonography.The overall clinical pregnancy rate for FET and TET cycles in 2012 was higher than in 2011 (33.7% vs. 33.2% and 36.1% vs. 31.1%, respectively). The most common number of embryos transferred in FET cycles was 2, unlike in 2011.