Effect of different endometrial preparation protocols on pregnancy outcomes in frozen- embryo transfer cycles: a retrospective cohort study

Abstract Background Owing to the crucial role the endometrium plays in embryo implantation, the four main endometrial preparation protocols have become important factors in the study of pregnancy outcomes in the FET cycles. Previous studies have shown that the best of these four protocols remains controversial for women undergoing FET. Methods A total of 10333 FET cycles from January 2018 to December 2018 were analyzed in this study. They were categorized into four groups according to endometrial preparation regimen: natural cycles (Group NC,n = 815), hormone replacement therapy cycles (Group HRT ,n = 6434), GnRH agonist artificial cycles (Group GAC,n = 1392) and ovarian stimulation cycles (Group OC, n = 1692). All patients were followed up for at least 1 year. Pregnancy outcomes were compared between the four groups and multiple logistic regression models were used to adjust for the effects of confounding factors. Results The ectopic pregnancy rate (P = 0.627) and miscarriage rate (P = 0.164) were not statistically significant between the four groups. Moreover, biochemical pregnancy rate, clinical pregnancy rate and live birth rate in the NC group were not statistically significant compared to the other three groups. After adjusting for covariates, multiple logistic regression analysis showed no statistical significance in pregnancy outcomes in the HRT, GAC and OC groups compared to the NC group.And the adjusted OR for live births was 0.988 (95 % CI0.847-1.152) for the HRT group, 0.955 (95 % CI0.795-1.146) for the GAC group,0.898 (95 % CI0.754-1.070) for the OC group. Conclusions Our study showed that natural cycles have similar pregnancy outcomes in terms of clinical pregnancy and live birth to the other three endometrial preparation options. As it has other advantages, the natural cycle protocol can therefore be the recommended option for endometrial preparation in the FET population.

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Gonadotropin-releasing hormone agonist combined with hormone replacement therapy improves pregnancy outcome in intrauterine adhesion

10.21203/rs.3.rs-342162/v1 ◽

2021 ◽

Author(s):

Meilan Mo ◽

Qizhen Zheng ◽

Hongzhan Zhang ◽

Shiru Xu ◽

Fen Xu ◽

...

Keyword(s):

Logistic Regression ◽

Live Birth ◽

Subgroup Analysis ◽

Pregnancy Outcomes ◽

Preparation Method ◽

Clinical Pregnancy ◽

Ongoing Pregnancy ◽

Endometrial Preparation ◽

Significant Difference ◽

Early Miscarriage

Abstract Objective: This retrospective study aimed to explore the optimal endometrial preparation method in women with intrauterine adhesions (IUAs).Method: A total of 882 frozen-thawed embryo transfer (FET) cycles were categorized into three groups based on endometrial preparation methods: hormone replacing therapy cycle (HRT, n=636), natural cycle (NC n=174), and HRT with GnRH-a pretreatment (HRT+GnRH-a, n=72. Logistic regression was performed to investigate the association between cycle regimens and pregnancy outcomes. Subgroup analysis of IUAs combined with thin endometrium (≤7mm) was also performed.Results: HRT with GnRH-a pretreatment was associated with higher incidences of clinical pregnancy, ongoing pregnancy, and live birth, but lower early miscarriage compared with either HRT or NC. Logistic regression indicated that after controlling for potential confounders, the incidences of live birth (HRT+GnRH-a as reference; NC: aOR=0.577, 95%CI 0.304-1.093; HRT: aOR=0.434, 95%CI 0.247-0.765) and ongoing pregnancy (NC: aOR=0.614, 95%CI 0.324-1.165; HRT: aOR=0.470, 95%CI 0.267-0.829) remained significantly higher in HRT+GnRH-a compared to those in HRT, but comparable to those in NC. While there was no significant difference with respect to the clinical pregnancy rate (NC: aOR=0.695, 95%CI 0.374-1.291; HRT: aOR=0.650, 95%CI 0.374-1.127) and early miscarriage rate (NC: aOR=1.734, 95%CI 0.417-7.175; HRT: aOR=2.594, 95%CI 0.718-9.378) between groups. Subgroup analysis suggested there was no priority of endometrial preparation method in IUAs combined with thin endometrium.Conclusion: HRT with GnRH-a pretreatment improves pregnancy outcomes in women with history of IUAs. GnRH-a may restore the endometrial receptivity in the FET cycles in IUAs.

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P–652 Higher live birth rates with controlled ovarian stimulation vs. natural cycles in donor sperm IUI

Human Reproduction ◽

10.1093/humrep/deab130.651 ◽

2021 ◽

Vol 36 (Supplement_1) ◽

Author(s):

C Lubamba

Keyword(s):

Pregnancy Rate ◽

Live Birth ◽

Pregnancy Outcomes ◽

Ovarian Stimulation ◽

Study Groups ◽

Good Prognosis ◽

Clinical Pregnancy ◽

Controlled Ovarian Stimulation ◽

Donor Sperm ◽

Natural Cycles

Abstract Study question Are pregnancy rates after intra uterine insemination-donor sperm (IUI-D) in good prognosis patients with controlled ovarian stimulation (COS) different from those in natural cycles? Summary answer In good prognosis patients, IUI-D cycles with COS provided higher pregnancy outcomes compared to IUI-D in natural cycles. What is known already There is no consensus about the systematic use of COS for IUI-D in good prognosis patients, considering efficacy, safety, and efficiency. The objective of this study is to compare the clinical pregnancy rate in good prognosis patients undergoing an IUI-D cycle with COS versus natural cycle (NC). Study design, size, duration Retrospective cohort study of 5,369 first IUI-D performed between January 2012 and September 2019 in one fertility center. IUI-D with COS (n = 4,417) versus natural cycles (n = 952) were compared. Differences in pregnancy outcomes between study groups were evaluated using a Pearson’s Chi2 test. A p < 0.05 was considered statistically significant. Participants/materials, setting, methods Good prognosis patients were defined as women aged ≤38 years old, with a BMI ≤35 Kg/m2, and having regular menses. The indications for IUI-D were an absence of male partner or a sever partner male factor. COS consisted in a standard protocol of r-FSH or hMG-HP, in a dose between 25 IU to 75 IU, depending on the patient’s age and the acceptance of multiple pregnancy, to obtain between 1 to 2 follicles at ovulation. Main results and the role of chance Average age was slightly higher in COS patients (33.0±3.8 versus 31.6±4.1 years old in NC), as was BMI (23.7±3.6 in COS vs 23.08±4.1 in NC). Further, in the last follicular control, estradiol was higher (321±180 vs 244±108 pg/ml), LH was lower in (14 vs 28 UI/L), and the number of follicles > 16mm was higher (1.06±0.5 vs 0.96±0.4) in COS vs NC, respectively. Progesterone levels did not differ between groups. Stimulated cycles provided significantly better results for all pregnancy outcomes (p < 0.001): biochemical pregnancy rate was 27.8% in COS versus 23.0% in NC; clinical pregnancy rate was 20.5% versus 14.8%; ongoing pregnancy rate was 18.5% versus 13.3%; and live birth rate was 16.8% versus 12.3%. While the analysis was not adjusted for potential confounding factors, baseline characteristics between groups were very similar, so we could expect that the improved reproductive results were due to COS. Limitations, reasons for caution The main limitation of the study is its retrospective nature and the collection of data from one clinic. Differences found between study groups should be confirmed in a prospective controlled trial. Wider implications of the findings: In good prognosis patients undergoing their first IUI-D, controlled ovarian stimulation provides better reproductive outcomes; further analysis of cumulative pregnancy rate after 3 cycles would provide information for recommendations on the complete treatment cycle. Trial registration number non applicable

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Effect of blastocyst morphology and developmental speed on transfer strategy for grade “C” blastocyst in vitrified‐warmed cycles

Journal of Ovarian Research ◽

10.1186/s13048-021-00798-w ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Yuxia He ◽

Shiping Chen ◽

Jianqiao Liu ◽

Xiangjin Kang ◽

Haiying Liu

Keyword(s):

Pregnancy Rate ◽

Live Birth ◽

Pregnancy Outcomes ◽

Multiple Pregnancy ◽

Poor Quality ◽

Clinical Pregnancy ◽

Neonatal Outcomes ◽

Blastocyst Transfer ◽

Blastocyst Development ◽

Multiple Pregnancy Rate

Abstract Background High-quality single blastocyst transfer (SBT) is increasingly recommended to patients because of its acceptable pregnancy outcomes and significantly reduced multiple pregnancy rate compared to double blastocyst transfer (DBT). However, there is no consensus on whether this transfer strategy is also suitable for poor-quality blastocysts. Moreover, the effect of the development speed of poor-quality blastocysts on pregnancy outcomes has been controversial. Therefore, this study aimed to explore the effects of blastocyst development speed and morphology on pregnancy and neonatal outcomes during the frozen embryo transfer (FET) cycle of poor-quality blastocysts and to ultimately provide references for clinical transfer strategies. Methods A total of 2,038 FET cycles of poor-quality blastocysts from patients 40 years old or less were included from January 2014 to December 2019 and divided based on the blastocyst development speed and number of embryos transferred: the D5-SBT (n = 476), D5-DBT (n = 365), D6-SBT (n = 730), and D6-DBT (n = 467) groups. The SBT group was further divided based on embryo morphology: D5-AC/BC (n = 407), D5-CA/CB (n = 69), D6-AC/BC (n = 580), and D6-CA /CB (n = 150). Results When blastocysts reach the same development speed, the live birth and multiple pregnancy rates of DBT were significantly higher than those of SBT. Moreover, there was no statistical difference in the rates of early miscarriage and live birth between the AC/BC and CA/CB groups. When patients in the SBT group were stratified by blastocyst development speed, the rates of clinical pregnancy (42.44 % vs. 20.82 %) and live birth (32.35 % vs. 14.25 %) of D5-SBT group were significantly higher than those of D6-SBT group. Furthermore, for blastocysts in the same morphology group (AC/BC or CA/CA group), the rates of clinical pregnancy and live birth in the D5 group were also significantly higher than those of D6 group. Conclusions For poor-quality D5 blastocysts, SBT can be recommended to patients because of acceptable pregnancy outcomes and significantly reduced multiple pregnancy rate compared with DBT. For poor-quality D6, the DBT strategy is recommended to patients to improve pregnancy outcomes. When blastocysts reach the same development speed, the transfer strategy of selecting blastocyst with inner cell mass “C” or blastocyst with trophectoderm “C” does not affect the pregnancy and neonatal outcomes.

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Hormone Replacement Therapy With GnRH Agonist Pretreatment Improves Pregnancy Outcomes in Patients With Previous Intrauterine Adhesions: a Retrospective Study

10.21203/rs.3.rs-627279/v1 ◽

2021 ◽

Author(s):

Meilan Mo ◽

Qizhen Zheng ◽

Hongzhan Zhang ◽

Shiru Xu ◽

Fen Xu ◽

...

Keyword(s):

Logistic Regression ◽

Retrospective Study ◽

Pregnancy Outcomes ◽

Preparation Method ◽

Clinical Pregnancy ◽

Ongoing Pregnancy ◽

Intrauterine Adhesions ◽

Endometrial Preparation ◽

History Of ◽

Early Miscarriage

Abstract Objective: This retrospective study aimed to explore the optimal endometrial preparation method in women with intrauterine adhesions (IUAs).Method: A total of 882 frozen-thawed embryo transfer (FET) cycles from patients with history of IUAs were categorized into three groups based on endometrial preparation methods: hormone replacing therapy cycle (HRT, n=636), natural cycle (NC n=174), and HRT with GnRH-a pretreatment (HRT+GnRH-a, n=72. Logistic regression was performed to investigate the association between cycle regimens and pregnancy outcomes. Subgroup analysis of IUAs combined with thin endometrium (≤7mm) was also performed.Results: HRT with GnRH-a pretreatment was associated with higher incidences of clinical pregnancy, ongoing pregnancy, and live birth, but lower early miscarriage compared with either HRT or NC. Logistic regression indicated that after controlling for potential confounders, the incidences of live birth (HRT+GnRH-a as reference; NC: aOR=0.577, 95%CI 0.304-1.093; HRT: aOR=0.434, 95%CI 0.247-0.765) and ongoing pregnancy (NC: aOR=0.614, 95%CI 0.324-1.165; HRT: aOR=0.470, 95%CI 0.267-0.829) remained significantly higher in HRT+GnRH-a compared to those in HRT, but comparable to those in NC. While there was no significant difference with respect to the clinical pregnancy rate (NC: aOR=0.695, 95%CI 0.374-1.291; HRT: aOR=0.650, 95%CI 0.374-1.127) and early miscarriage rate (NC: aOR=1.734, 95%CI 0.417-7.175; HRT: aOR=2.594, 95%CI 0.718-9.378) between groups. Subgroup analysis suggested there was no superiority of endometrial preparation method in IUAs combined with thin endometrium.Conclusion: HRT with GnRH-a pretreatment improves pregnancy outcomes in women with history of IUAs. GnRH-a may restore the endometrial receptivity in the FET cycles in IUAs.

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Uterus Size May Affect Reproductive Outcome in Women with Adenomyosis After Gnrh- Agonist Pretreatment Undergoing Frozen Embryo Transfer Cycles: A Retrospective Cohort Study

10.21203/rs.3.rs-122461/v1 ◽

2020 ◽

Author(s):

Wei Xiong ◽

Ruiyi Tang ◽

Peng Wu ◽

Zhengyi Sun ◽

jingran zhen ◽

...

Keyword(s):

Cohort Study ◽

Pregnancy Rate ◽

Embryo Transfer ◽

Live Birth ◽

Gnrh Agonist ◽

Retrospective Cohort Study ◽

Pregnancy Outcomes ◽

Retrospective Cohort ◽

Clinical Pregnancy ◽

Frozen Embryo Transfer

Abstract Background: GnRH-agonist is used to treat adenomyosis, but its efficacy in adenomyosis patients with uterine enlargement undergoing frozen embryo transfer (FET) is unclear. Methods：The retrospective cohort study comprised 112 adenomyosis patients with uterine enlargement undergoing the first FET circle. A long-term GnRH-a pretreatment was administered to 112 patients with uterine enlargement. These patients were divided into two groups according to the therapeutic effect: patients with a normal-size uterus after GnRH-a treatment (GN group) and patients with an enlarged uterus after GnRH-a treatment (GL group). Results：Not all patients can shrink their uterus to a satisfactory level. After receiving GnRH-a pretreatment, the uterus returned to normal size in 77% of patients (GN group), and 23% of patients had a persistently enlarged uterus (GL group). The pregnancy rate, clinical pregnancy rate, ongoing pregnancy rate, and live birth rate were significantly higher in the GN group than in the GL group. Controlling for the confounding factors, normal uterus size (odds ratio [OR] 4.50; P=0.03) and low body mass index (OR 3.13; P=0.03) affected the odds of achieving live birth. The cut-off value selected on the ROC curve of uterus volume after GnRH-a treatment for detecting live birth was 144.7Conclusions：GnRH-a pretreatment was associated with the regression of adenomyosis lesions and improved clinical pregnancy outcomes in the adenomyosis patients with uterine enlargement whose lesion are GnRH-a susceptible on FET cycles. However, about a quarter of patients may not be less responsive to GnRH-a and have poorer pregnancy outcomes, especially in overweight women.

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Effect of Blastocyst Morphology and Developmental Speed on Transfer Strategy for Grade “C” Blastocyst in Vitrified-warmed Cycles

10.21203/rs.3.rs-136802/v1 ◽

2021 ◽

Author(s):

yuxia He ◽

shiping Chen ◽

jianqiao Liu ◽

xiangjin Kang ◽

haiying Liu

Keyword(s):

Pregnancy Rate ◽

Live Birth ◽

Pregnancy Outcomes ◽

Multiple Pregnancy ◽

Poor Quality ◽

Clinical Pregnancy ◽

Neonatal Outcomes ◽

Blastocyst Transfer ◽

Blastocyst Development ◽

Multiple Pregnancy Rate

Abstract Background: High-quality single blastocyst transfer (SBT) is increasingly recommended to patients because of its acceptable pregnancy outcomes and significantly reduced multiple pregnancy rate compared to double blastocyst transfer (DBT). However, there is no consensus on whether this transfer strategy is also suitable for poor-quality blastocysts. Moreover, the effect of the development speed of poor-quality blastocysts on pregnancy outcomes has been controversial. Therefore, this study aimed to explore the effects of blastocyst development speed and morphology on pregnancy and neonatal outcomes during the frozen embryo transfer (FET) cycle of poor-quality blastocysts and to ultimately provide references for clinical transfer strategies.Methods: A total of 2,038 FET cycles of poor-quality blastocysts were analyzed from January 2014 to December 2019 and divided based on the blastocyst development speed and number of embryos transferred: the D5-SBT (n=476), D5-DBT (n=365), D6-SBT (n=730), and D6-DBT (n=467) groups. The SBT group was further divided based on embryo morphology: D5-AC/BC (n=407), D5-CA/CB (n=69), D6-AC/BC (n=580), and D6-CA /CB (n=150).Results: When blastocysts reach the same development speed, the live birth and multiple pregnancy rates of DBT were significantly higher than those of SBT. Moreover, there was no statistical difference in the rates of early miscarriage and live birth between the AC/BC and CA/CB groups. When patients in the SBT group were stratified by blastocyst development speed, the rates of clinical pregnancy (42.44% vs. 20.82%) and live birth (32.35% vs. 14.25%) of D5-SBT group were significantly higher than those of D6-SBT group. Furthermore, for blastocysts in the same morphology group (AC/BC or CA/CA group), the rates of clinical pregnancy and live birth in the D5 group were also significantly higher than those of D6 group. Conclusion: For poor-quality D5 blastocysts, SBT can be recommended to patients because of acceptable pregnancy outcomes and significantly reduced multiple pregnancy rate compared with DBT. For poor-quality D6, the DBT strategy is recommended to patients to improve pregnancy outcomes. When blastocysts reach the same development speed, the transfer strategy of selecting blastocyst with inner cell mass “C” or blastocyst with trophectoderm “C” does not affect the pregnancy and neonatal outcomes.

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Effects of artificial cycles with and without gonadotropin-releasing hormone agonist pretreatment on frozen embryo transfer outcomes

Journal of International Medical Research ◽

10.1177/0300060520918474 ◽

2020 ◽

Vol 48 (6) ◽

pp. 030006052091847

Author(s):

Qianrong Qi ◽

Jin Luo ◽

Yaqin Wang ◽

Qingzhen Xie

Keyword(s):

Pregnancy Rate ◽

Embryo Transfer ◽

Live Birth ◽

Pregnancy Outcomes ◽

Polycystic Ovarian Syndrome ◽

Gonadotropin Releasing Hormone ◽

Clinical Pregnancy ◽

Frozen Embryo Transfer ◽

Gonadotropin Releasing Hormone Agonist ◽

Ovarian Syndrome

Objective This study aimed to compare the pregnancy outcomes between women receiving frozen embryo transfer (FET) with hormone replacement treatment (HRT) with and without gonadotropin-releasing hormone agonist (GnRHa) pretreatment. Methods All consecutive women undergoing HRT cycles (2936 cycles) or HRT with GnRHa pretreatment (HRT + GnRHa, 303 cycles) at our reproductive center between January 2015 and December 2017 were analyzed retrospectively. Results The average age was higher in the HRT + GnRHa compared with the HRT group (34.0 ± 4.8 vs. 31.3 ± 4.4). However, the pregnancy outcomes were comparable between the two groups. The clinical pregnancy rate was significantly increased in younger women (≤35 years) in the HRT + GnRHa group compared with the HRT group (56.8% vs. 48.7%), but the live birth rates were similar in the two groups (44.2% vs. 38.4%). The HRT + GnRHa protocol significantly increased the clinical pregnancy rate (55.6% vs. 43.2%) and live birth rate (43.5% vs. 33.5%) compared with the HRT group among women with endometriosis, and significantly decreased the abortion rate in women with polycystic ovarian syndrome (3.1% vs. 16.4%). Conclusions GnRHa pretreatment may improve pregnancy outcomes in women with endometriosis and polycystic ovarian syndrome.

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Effect of Blastocyst Morphology and Developmental Speed on Transfer Strategy for Grade “C” Blastocyst in Vitrified-Warmed Cycles

10.21203/rs.3.rs-143382/v1 ◽

2021 ◽

Author(s):

Yuxia He ◽

Shiping Chen ◽

Jianqiao Liu ◽

Xiangjin Kang ◽

Haiying Liu

Keyword(s):

Pregnancy Rate ◽

Live Birth ◽

Pregnancy Outcomes ◽

Multiple Pregnancy ◽

Poor Quality ◽

Clinical Pregnancy ◽

Neonatal Outcomes ◽

Blastocyst Transfer ◽

Blastocyst Development ◽

Multiple Pregnancy Rate

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Self-Reported Inability to Cry as a Symptom of Anhedonic Depression in Outpatients with a Major Depressive Disorder

Psychological Reports ◽

10.2466/02.09.13.15.pr0.108.3.874-882 ◽

2011 ◽

Vol 108 (3) ◽

pp. 874-882 ◽

Cited By ~ 4

Author(s):

Roberta Steer

Keyword(s):

Logistic Regression ◽

Major Depressive Disorder ◽

Regression Analysis ◽

Depressive Disorder ◽

Multiple Logistic Regression Analysis ◽

The Other ◽

Multiple Logistic Regression ◽

Major Depressive ◽

Dsm Iv ◽

Anhedonic Depression

To ascertain whether self-reported inability to cry would be associated with symptoms of anhedonic depression, the 21-item Beck Depression Inventory-II was administered to 1,050 outpatients diagnosed with a DSM-IV-TR major depressive disorder. 219 (21%) patients reported on the BDI-II Crying item that they were unable to cry, and 831 (79%) patients reported they were able to cry. Only BDI-II Loss of Interest was significantly associated with the inability to cry after the other BDI-II symptoms were controlled for using a multiple logistic-regression analysis. The inability to cry was discussed as an indicator of anhedonic depression.

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P–359 Blastocyst quality, transfer difficulty and endometrial thickness affect clinical pregnancy after frozen embryo transfer (FET) of euploid blastocysts in the upper uterine cavity

Human Reproduction ◽

10.1093/humrep/deab130.358 ◽

2021 ◽

Vol 36 (Supplement_1) ◽

Author(s):

A Bayram ◽

N D Munck ◽

A Abdala ◽

I Elkhatib ◽

A El-Damen ◽

...

Keyword(s):

Pregnancy Rate ◽

Embryo Transfer ◽

Pregnancy Outcomes ◽

Endometrial Thickness ◽

Uterine Cavity ◽

Small Sample ◽

Clinical Pregnancy ◽

Clinical Pregnancy Rate ◽

Endometrial Preparation ◽

Blastocyst Quality

Abstract Study question Which factors affect the clinical pregnancy rate (CPR) after single euploid frozen embryo transfers (FET), when the blastocyst is transferred in the upper uterine cavity area? Summary answer Blastocyst quality, embryo transfer difficulty and endometrial thickness affect the CPR in FET. What is known already There is a limited understanding of the factors affecting success rates after FET. The most important factors influencing implantation rates are patient characteristics, type of endometrial preparation, embryo quality and transfer difficulty. It has been shown that the position of the euploid blastocyst, measured as distance from the fundus (DFF) of the uterine cavity (mm), affects the implantation potential. Although the ideal location within the uterine cavity is still being debated in very heterogeneous patient populations, most studies have found that the highest pregnancy rates are obtained when the embryo is placed in the upper area of the uterine cavity. Study design, size, duration This single center retrospective cohort study included a total of 603 single euploid FET cycles, in the upper half of the uterine cavity, between January 2019 and November 2020 in ART Fertility Clinic Abu Dhabi, UAE. Participants/materials, setting, methods Trophectoderm biopsy samples were subjected to Next Generation Sequencing to screen the ploidy state. Vitrification and warming were performed using the Cryotop method (Kitazato, Biopharma). The full length of the uterine cavity and the longitudinal distance between the fundal endometrial surface and the air bubble after transfer were measured. Main results and the role of chance The patients were on average 33.9 (19–46) years old. The FET was performed in a natural cycle (NC) (n = 278) or hormone replacement therapy (HRT) (n = 325). Of the 603 transfers which had been performed in the upper half of the uterus, 412 (68.3%) resulted in a pregnancy and 311 (51.5%) in a clinical pregnancy. After bivariate analysis, the clinical pregnancy rate was significantly higher for high quality blastocysts (grade 1–2 versus 3–4) (p < 0.001), after easy embryo transfers (p = 0.001) and for higher endometrial thickness (p = 0.027). After performing a multivariate logistic regression analysis to consider the effect of all explanatory variables (age, Anti Müllerian hormone, body mass index, endometrial thickness, quality of the blastocyst, difficulty of the transfer [requirement of additional instrumentation], presence of mucus or blood on the transfer catheter, day 5 or day 6 biopsy, FET endometrial preparation), the clinical pregnancy was affected by the endometrial thickness: OR 1.20 [1.05–1.37], p = 0.007; transfer difficulty: OR 0.44 [0.25–0.79], p = 0.006; blastocyst quality 3: OR 0.38 [0.18–0.79], p = 0.01 and blastocyst quality 4: OR 0.15 [0.06–0.37], p < 0.0001. Age did not affect the clinical pregnancy after transferring a single euploid blastocyst: OR 1.03 [1.00–1.06], p = 0.052. Limitations, reasons for caution The limitation of this study was its retrospective nature and the small sample size. Other parameters may be important in live birth outcomes. Wider implications of the findings: Optimization of clinical pregnancy outcomes after FET depends on multiple factors. Even after transfer of euploid blastocysts in the upper uterine cavity, the endometrial thickness, transfer difficulty and blastocyst quality will still affect the clinical pregnancy outcomes. Trial registration number NA

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