The objective of this study was to examine the influence of repeated embryo implantation failures on pregnancy outcomes among patients under 40 years of age undergoing in vitro fertilization/intracytoplasmic sperm injection embryo transfer (IVF/ICSI-ET).
A retrospective analysis was conducted on the clinical data of 13,172 patients who underwent 16,975 IVF/ICSI-ET treatment cycles at Henan Reproductive Hospital between January 1, 2015, and December 31, 2018. Patients were categorized into four groups based on the number of previous embryo implantation failure cycles: Group A=no implantation failure, Group B= 1 implantation failure, Group C=2 implantation failures, Group D=≥3 implantation failures. Baseline characteristics and pregnancy outcomes were compared among the four groups. The impact of the number of previous embryo implantation failures on pregnancy outcomes among IVF/ICSI-ET patients was investigated using univariate and multiple regression analyses.
Univariate logistic regression analysis demonstrated that factors such as the number of previous embryo implantation failures, female age, basal follicle count, endometrial thickness, total number of oocytes retrieved, type of cycle, number of high-quality embryos transferred, and stage of embryo development significantly affected implantation rate, clinical pregnancy rate, early spontaneous abortion rate, and live birth rate (all P < 0.05). The duration of infertility and anti-Mullerian hormone (AMH) levels were also found to influence implantation rate, clinical pregnancy rate, and live birth rate (all P < 0.05). Upon conducting multivariate logistic regression analysis and adjusting for confounding factors such as age, AMH levels, basal follicle count, endometrial thickness, total number of oocytes obtained, cycle type, number of high-quality embryos transferred, ovarian stimulation protocol, and stage of embryo development, it was revealed that, compared to Group A, Groups B, C, and D exhibited significantly lower implantation and live birth rates, as well as a significantly higher risk of early spontaneous abortion (all P < 0.05).
The number of previous embryo implantation failures is an independent factor affecting implantation rate, clinical pregnancy rate, spontaneous abortion rate and live birth rate of patients underwent IVF/ICSI-ET. With the increase of the number of previous embryo implantation failures, the implantation rate, clinical pregnancy rate and live birth rate of patients underwent IVF/ICSI-ET decreased significantly, and the rate of early spontaneous abortion gradually increased.

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.
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.
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.
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.

This meta-analysis aimed to assess the reproductive competence of blastocysts developed on day 7 compared with blastocysts developed on day 5/6. A systematic search was carried out to select relevant studies published before January 2020. Ten retrospective observational cohort studies were included. The primary outcome was the clinical pregnancy rate (CPR). Secondary outcomes were live birth rate (LBR), euploid rate, and survival rates after thawing. Frozen-thawed day 7 blastocyst transfer was associated with a significant reduction in CPR compared to day 5/6 (OR 0.36 95% CI 0.21 to 0.62, p = 0.0002, I2 = 71% and OR 0.43, 95% CI 0.32 to 0.58, p < 0.0001, I2 = 17% respectively). A significantly lower proportion of LBR was found comparing blastocysts transfers in day 7 to those in day 5/6 (OR 0.21, 95% CI 0.16-0.27, p < 0.0001, I2 = 0% and OR 0.34, 95% CI 0.26-0.45, p < 0.0001, I2 = 0% respectively). These findings were confirmed in a subgroup of Preimplantation Genetic Testing for Aneuploidies (PGT-A)-screened blastocysts. Blastocysts biopsied in day 7 was associated with a significant decrease of euploid rate compared with day 5/6 (OR 0.47, 95% CI 0.39-0.57, p < 0.0001, I2 = 69% and OR 0.68, 95% CI 0.61-0.75, p < 0.0001, I2 = 19% respectively). The survival rate after thawing was not statistically different. Sensitivity analyses were also performed. This study shows an association between delayed blastulation and a poorer prognosis in terms of euploid rate and pregnancy outcomes following frozen-thawed transfers. On the other hand, the results do not support the discharge of slow-blastulation embryos.

UNASSIGNED: The advent of ovarian stimulation within an in vitro fertilization (IVF) cycle has resulted in modifying the physiology of stimulated cycles and has helped optimize pregnancy outcomes. In this regard, the importance of progesterone (P4) elevation at time of human chorionic gonadotrophin (hCG) administration within an IVF cycle has been studied over several decades. Our study aimed to evaluate the association of P4 levels at time of hCG trigger with live birth rate (LBR), clinical pregnancy rate (CPR) and miscarriage rate (MR) in fresh IVF or IVF-ICSI cycles.
UNASSIGNED: This was a retrospective cohort study (n=170) involving patients attending the Centre for Reproductive and Genetic Health (CRGH) in London. The study cohort consisted of women undergoing controlled ovarian stimulation using GnRH antagonist or GnRH agonist protocols. Univariate and multiple logistic regression analyses were used to evaluate the association of clinical outcomes. Differences were considered statistically significant if p≤0.05.
UNASSIGNED: As serum progesterone increased, a decrease in LBR was observed. Following multivariate logistical analyses, LBR significantly decreased with P4 thresholds of 4.0 ng/ml (OR 0.42, 95% CI:0.17-1.0) and 4.5 ng/ml (OR 0.35, 95% CI:0.12-0.96).
UNASSIGNED: P4 levels are important in specific groups and the findings were statistically significant with a P4 threshold value between 4.0-4.5 ng/ml. Therefore, it seems logical to selectively measure serum P4 levels for patients who have ovarian dysfunction or an ovulatory cycles and accordingly prepare the individualized management packages for such patients.

Objective: To assess the association between serum ovulation trigger progesterone (P) levels and the outcome of in vitro fertilization cycles. Design Setting: Real world single-center retrospective cohort study. Patient Intervention(s): All fresh cleavage and blastocyst-stage embryo transfers (ETs) performed from January 2012 to December 2016. Main outcome Measure(s): The impact of premature high serum P levels cycles in terms of clinical pregnancy rates (CPRs) and live birth rates (LBRs). Results: 8,034 ETs were performed: 7,597 cleavage-stage transfers and 437 blastocyst transfers. Serum P levels demonstrated to be inversely related to CPR (OR 0.72, p < 0.001) and LBR (OR 0.73, p < 0.001). The progressive decrease of LBR and CPR started when P levels were >1 ng/ml in a good prognosis cleavage ET subgroup, whereas in patients with worse prognosis only for P ≥ 1.75 ng/ml. In the blastocyst ET subgroup, the negative effect of P elevation was reported only if P was >1.75 ng/ml. CPR (OR 0.71 (0.62-0.80), p < 0.001) and LBR (OR 0.73 (0.63-0.84), p < 0.001) in thawed cycles resulted statistically significantly higher than in fresh cycles in the cleavage-stage subgroup. In the blastocyst group, no significant difference resulted between thawed and fresh cycles, independently of P levels [CPR OR 0. 37 (0.49-1.09), p = 0.123; LBR OR 0.71 (0.46-1.10), p = 0.126]. Conclusion: High P levels decrease CPR as well as LBR in both cleavage and blastocyst ET. In the cleavage group, for P levels below 1.75 ng/ml, our data suggest the possibility to wait until day 5 for ET, and if P level is ≥1.75 ng/ml, it should be considered to freeze all embryos and postpone the ET. Clinical Trial Registration: ClinicalTrials.gov, ID: NCT04253470.