Major Factors Affecting the Live Birth Rate After Frozen Embryo Transfer Among Young Women

Inverse association of prepregnancy systolic blood pressure and live birth rate in normotensive women undergoing in vitro fertilization/intracytoplasmic sperm injection

OBJECTIVE

To explore whether maternal baseline systolic blood pressure (SBP) and diastolic blood pressure (DBP) affect pregnancy outcomes particularly in normotensive women (SBP, 90-139 mm Hg; DBP, 60-89 mm Hg) and hypertensive women undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI).

DESIGN

Retrospective cohort study.

SETTING

Maximum care hospital for reproductive medicine.

PATIENT(S)

This study included 73,462 patients who underwent IVF/ICSI at the Reproductive and Genetic Hospital of CITIC-Xiangya between January 1, 2016, and November 30, 2020, selected on the basis of pre-established criteria. Analysis was limited to the first transfer cycle of the first stimulation cycle.

INTERVENTION

Baseline SBP and DBP.

MAIN OUTCOME MEASURE(S)

The primary outcome focused on the live birth rate (LBR), with the secondary outcomes including clinical pregnancy rate, ectopic pregnancy rate, first-trimester miscarriage rate, second- or third-trimester fetal loss, and delivery/neonatal/maternal outcomes. Analytic methods included Poisson regression, linear regression, linear mixed-effect model, and restricted cubic spline analysis as appropriate.

RESULT(S)

For normotensive women, a 10-mm Hg increase in SBP was associated with an adjusted relative risk of 0.988 (95% confidence interval, 0.981-0.995) for live birth likelihood. However, DBP was not significantly associated with LBR after adjustments. The secondary outcomes indicated that increases in SBP and DBP were associated with higher risks of first-trimester miscarriage, gestational diabetes mellitus, and gestational hypertension in the normotensive subset. Sensitivity analyses confirmed these associations between SBP/DBP and LBR, consistent with the main findings even under stricter guidelines and after adjusting for multiple confounders. Subgroup analyses showed variation in the impact of blood pressure on LBR across different demographics and conditions. Consistent with earlier studies on blood pressure and birth outcomes, we found a 10-mm Hg increase in SBP was associated with a 5.4% (adjusted relative risk per 10 mm Hg, 0.946; 95% confidence interval, 0.907-0.986) reduction in LBR in the hypertensive subgroup.

CONCLUSION(S)

Systolic blood pressure impacted LBR outcomes in normotensive women who underwent IVF/ICSI, which suggests the need for reconsidering blood pressure management guidelines for reproductive-age women, focusing on reproductive health in addition to cardiovascular risk.

Large-scale retrospective analysis of methodological factors affecting pregnancy rates after embryo transfer for in vitro fertilization

This study aimed to investigate the impact of methodological factors on pregnancy rates after embryo transfer (ET) for in vitro fertilization. This retrospective cross-sectional study was conducted between September 2020 and April 2022. A total of 2048 patients who underwent ultrasonography-guided first frozen embryo transfer (FET) or a fresh ET cycle due to infertility were included in the study. The effects of age, ET protocol (frozen or fresh), preimplantation genetic testing, number of embryos transferred (NET), and embryo fundus distance on pregnancy rate were investigated. The mean age of pregnant patients (31.51 ± 5.28) was significantly lower than that of non-pregnant patients (35.34 ± 6.39) (P < .001). Multiple regression analysis showed that women with lower age (P < .001), higher NET (P < .001), higher embryo fundus distance (P < .001), FET (P < .001), and preimplantation genetic testing (P = .012) had a significantly higher likelihood of pregnancy. Appropriate transfer depth, younger age, euploid embryo transfer, FET, and a higher NET can increase the likelihood of pregnancy. However, multiple factors must be considered when deciding the best protocol for a particular patient, including patient preference, costs and timing.

Screening the predictors for live birth failure in women after the first frozen embryo transfer based on the Lasso algorithm: a retrospective study

This study aimed to screen factors related to live birth outcomes of women with first frozen embryo transfer (FET). The enrolled women were divided into training and validation cohorts. The least absolute shrinkage and selection operator (Lasso) regression algorithm of machine learning and the multiple regression model were then used to screen factors relevant to live birth failure (LBF) for the training dataset. A nomogram risk prediction model was established on the basis of the screened factors, and the consistency index (C-index) and calibration curve were derived for evaluating the model. The validation cohort was utilized to validate the nomogram model further. In total, 2083 women who accepted the first FET in our hospital were included and 44 factors were initially screened in this study. On the basis of the training cohort, the screened risk factors via multiple regression analysis with odds ratio (OR) values were female age (OR: 3.092, 95%CI: 1.065-4.852), body mass index (BMI; OR: 1.106, 95%CI: 1.015-1.546), caesarean section (OR: 1.909, 95%CI: 1.318-2.814), number of high-quality embryos (OR: 0.698, 95%CI: 0.599-0.812), and endometrial thickness (OR: 0.957, CI: 0.904-0.980). The nomogram model was generated based on five predictors. Furthermore, favourable results with C-indexes and calibration curves close to ideal curves indicated the accurate predictive ability of the nomogram. Female age, BMI, caesarean section, number of high-quality embryos, and endometrial thickness were independent predictors for LBF. The five factors of the risk assessment model may help to identify LBF with high accuracy in women who accept FET.

Clinical and laboratory parameters associated with pregnancy outcomes in patients undergoing frozen euploid blastocyst transfer

RESEARCH QUESTION

Which factors impact on clinical pregnancy rate (CPR) and live birth rates (LBR) in euploid frozen embryo transfer (eFET) cycles?

DESIGN

Retrospective observational study including 1660 eFET cycles with 2439 euploid blastocysts, from November 2016 to December 2020. The impact of clinical and laboratory parameters on CPR, biochemical miscarriage rate (BMR), clinical miscarriage rate (CMR) and LBR was evaluated.

RESULTS

CPR per transfer was 63.4%, LBR per transfer 51.6%. CPR and LBR were significantly higher when double embryo transfer (DET) was performed (71.6% versus 57.7%, P < 0.001; 55.2% versus 49.1%, P = 0.016, respectively). However, pregnancy loss was significantly higher in the DET group (28.8% versus 22.8%, P = 0.02). When patients were classified by body mass index (BMI), no differences were observed for CPR, but CMR was lower (P < 0.001) and LBR higher (p = 0.031) for the normal BMI group. The natural cycle protocol revealed lower CMR (P < 0.001) and lower pregnancy loss (P < 0.001); subsequently, higher LBR (57.6%, 48.8%, 45.0%, P = 0.001) compared with hormonal replacement protocol and stimulated cycle. Day of trophectoderm biopsy affected CPR (P < 0.001) and LBR (P < 0.001), yet no differences were observed for BMR, CMR or pregnancy loss. The multivariate analysis showed that day 6/7 embryos had lower probabilities for pregnancy; overweight and obesity had a negative impact on LBR, and natural cycle improved LBR (adjusted odds ratio 1.445, 95% confidence interval 0.519-0.806).

CONCLUSIONS

Day of biopsy affected CPR, while BMI and endometrial preparation protocol were associated with LBR in eFET. DET should be discouraged as it will increase the risk of pregnancy loss. Women with higher BMI should be aware of the higher risk of pregnancy loss and lower LBR even though a euploid blastocyst is transferred.

Is the length of time between endometrial scratching and embryo transfer important for pregnancy success? An observational study

OBJECTIVE

This study sought to evaluate the influence of time (early <90 days and late >90 days) and endometrial injury on pregnancy success.

METHODS

This is a retrospective study in which all infertile women who underwent at least one in vitro fertilization cycle at Clinica Gera between 2010 and 2015 were considered for inclusion. We included patients with a normal ovarian reserve and regular menses at intervals of up to 30 days. A total of 315 patient files were reviewed, and the study group was composed of patients who faced fertility issues and had male-caused infertility or idiopathic infertility. Also, women with male or unknown cause of infertility who have performed endometrial biopsy and have undergone embryo transfer up to 180 days after this procedure between 2010 and 2015 were included. The patients were divided into two groups according to the interval between biopsy and embryo transfer: group 1 (early-an interval of <90 days) and group 2 (late-an interval of >90 days and up to 180 days).

RESULTS

The results were superior for the group with an interval of less than 90 days relative to the group with an interval of more than 90 days (p<0.04). The pregnancy rates for group 1 and group 2 were 58.5% and 43.4%, respectively. The odds ratio for pregnancy success was 1.63 (95% confidence interval: 1.04 to 2.55).

CONCLUSION

The early transfer of embryos (<90 days) may produce better results with a high rate of pregnancy. Further studies are necessary to identify the mechanism involved in this phenomenon.

Association of the Cumulative Live Birth Rate with the Factors in Assisted Reproductive Technology: A Retrospective Study of 16,583 Women

The cumulative live birth rate (CLBR) can better reflect the overall treatment effect by successive treatments, and continuous rather than categorical variables as exposure variables can increase the statistical power in detecting the potential correlation. Therefore, the dose-response relationships might find an optimal dose for the better CLBR, offering evidence-based references for clinicians. To determine the dose-response relationships of the factors and the optimal ranges of the factors in assisted reproductive technology (ART) associated with a higher CLBR, this study retrospectively analyzed 16,583 patients undergoing the first in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) from January 2017 to January 2019. Our study demonstrated the optimal ranges of age with a higher CLBR were under 32.10 years. We estimated the CLBR tends to increase with increased levels of AMH at AMH levels below 1.482 ng/mL, and the CLBR reaches a slightly high level at AMH levels in the range from 2.58-4.18 ng/mL. The optimal ranges of basal FSH with a higher CLBR were less than 9.13 IU. When the number of cryopreserved embryos was above 1.055 and the number of total transferred embryos was 2, the CLBR was significantly higher. In conclusion, there is a non-linear dose-response relationship between the CLBR with age, AMH, basal FSH, and the number of cryopreserved embryos and total transferred embryos. We proposed the optimal ranges of the five factors that were correlated with a higher CLBR in the first oocyte retrieval cycle, which may help consultation at IVF clinics.

Frozen-thawed embryo transfer in modified natural cycles: a retrospective analysis of pregnancy outcomes in ovulatory women with vs. without spontaneous luteinizing hormone surge

Background

Timing of frozen embryo transfer (FET) in natural endometrial preparation cycles is often based on luteinizing hormone (LH) surge. However, some patients do not show spontaneous LH surge despite follicular maturation. The objective of this study was to evaluate the impact of spontaneous LH surge on pregnancy outcomes in modified natural cycles (mNC).

Methods

This retrospective analysis included 1897 FET cycles with modified natural endometrial preparation in normo-ovulatory women between January 1, 2015, to December 31, 2019, at our center: 920 cycles with spontaneous LH surge (≥ 20 IU/L) and 977 without. For cleavage embryos, FET was conducted 4 and 5 days after hCG injection in women with and without LH surge, respectively. For blastocysts, FET was conducted 6 and 7 days after hCG injection in women with and without LH surge, respectively. Multivariate regression was conducted to examine the factors associated with live birth.

Results

Live birth rate was 43.7% in patients with spontaneous LH surge vs. 43.8% in women without LH surge (P = 0.961). The two groups also had similar implantation rate (36.2% vs. 36.7%, P = 0.772), biochemical pregnancy rate (54.8% vs. 55.4%, P = 0.796) and clinical pregnancy rate (50.9% vs. 51.7%, P = 0.721). In multivariate regression, live birth was not associated with LH surge (aOR, 0.947, 95% CI, 0.769, 1.166).

Conclusion

Pregnancy outcomes were similar in mNC-FET in cycles with vs. without spontaneous LH surge if FET timing is adjusted.

Higher baseline alanine aminotransferase level is associated with lower live birth rate after freeze-thawed embryo transfer

OBJECTIVE

The aim of this retrospective analysis was to explore whether an elevated ALT level before pregnancy is associated with a reduction in live birth rate after IVF-FET.

DESIGN

Retrospective observational study.

SETTING

Shiyan People's Hospital, China between January 2019 and December 2019.

PATIENTS

Women aged ≤ 40 years.

INTERVENTION(S)

Freeze-thawed embryo transfer (FET).

MAIN OUTCOME MEASURE(S)

The live birth rate, which was defined as the delivery of a live baby after 24 weeks of gestation.

RESULTS

The analysis included 365 FET cycles. There was a significant difference between groups in the live birth rate (p < .05), which was highest for the low ALT tertile and lowest for the high ALT tertile. Multiple regression analysis with adjustment for multiple potential confounders revealed that the odds of live birth were decreased for each one standard deviation increase in ALT (OR = 0.56, 95%CI = 0.42-0.75, p < .0001) and lower for the high ALT tertile than for the low ALT tertile (OR = 0.38, 95%CI = 0.19-0.75, p = .0055). Smooth curve fitting showed an inverse relationship between ALT and live birth rate.

CONCLUSION

Our findings indicate that relatively small elevations in baseline serum ALT level can have a clinically relevant impact on the success of FET.

Increased risk of abortion after frozen-thawed embryo transfer in women with polycystic ovary syndrome phenotypes A and D

Polycystic ovary syndrome (PCOS) is associated with adverse pregnancy outcomes, including an increased risk of abortion, premature delivery, and even neonatal outcomes. After removing the effect of COH on patients, studying the pregnancy outcomes of patients with different PCOS phenotypes after FET may better reflect the impact of different PCOS phenotypes on ART outcomes. Data of 8903 patients who underwent FET between January 2017 and October 2019 were retrospectively collected and evaluated. All patients were divided into a control group and four phenotype groups based on Rotterdam criteria. The main outcomes were pregnancy outcomes after FET. We found significantly higher abortion (P = 0.010) and lower ongoing pregnancy (P = 0.023) rates for women with PCOS phenotypes A and D compared to those in the control group. After adjusting for potential confounders, PCOS phenotypes A and D were associated with an elevated risk of abortion (adjusted OR, 1.476, P = 0.016; adjusted OR, 1.348, P = 0.008, respectively). The results of this study suggest that when performing FET, clinicians should individually manage women with PCOS phenotypes A and D to reduce the rate of abortion and increase the rate of LB, and achieve better pregnancy outcomes.

Transcutaneous electrical acupoint stimulation improves endometrial receptivity resulting in improved IVF-ET pregnancy outcomes in older women: a multicenter, randomized, controlled clinical trial

OBJECTIVE

To examine the effects and mechanisms of transcutaneous electrical acupoint stimulation (TEAS) on pregnancy outcomes in women undergoing in vitro fertilization (IVF)-embryo transfer (ET).

DESIGN, SETTING, AND PARTICIPANTS

This efficacy study was a multicenter, randomized, controlled clinical trial (RCT) in women receiving IVF-ET. The mechanistic study was a single-center RCT.

INTERVENTIONS

The participants received TEAS vs. no TEAS treatment.

MAIN OUTCOME MEASURES

In the efficacy study, the primary outcomes were the rates of clinical pregnancy, embryo implantation, and live birth. In the mechanistic study, sex hormones and endometrial protein expression were examined.

RESULTS

Ultimately, 739 participants were enrolled (367 and 372 in the TEAS and control groups, respectively). The clinical pregnancy rate was higher in the TEAS group than in the controls (55.1% vs. 46.7%, P = 0.03). There were no significant differences in embryo implantation, biochemical pregnancy, and live birth rates between the two groups (all P > 0.05) in the study population. In women > 35 years, the clinical pregnancy rates, embryo implantation rates and live birth rates in the TEAS and control groups were 48.9% vs. 23.7% (P = 0.004),30.8 vs. 13.9% (P = 0.001) and 34.0% vs. 19.7% (P = 0.06) respectively. In the mechanistic study with 120 participants, on the theoretical embryo implantation day, better developed endometrial pinopodes, elevated endometrial integrin α1β1/αVβ3, leukemia inhibitory factor, and elevated serum progesterone levels were found in the TEAS group compared with controls.

CONCLUSION

TEAS significantly improved the clinical pregnancy rate in women undergoing IVF-ET, especially in women of older age. It might be due to improved endometrial receptivity.

TRIAL REGISTRATION

ChiCTR-TRC-13003950.

Influence of Maternal Age on the Relationship Between Endometrial Thickness and Ongoing Pregnancy Rates in Frozen-Thawed Embryo Transfer Cycles: A Retrospective Analysis of 2,562 Cycles

Background

In frozen-thawed embryo transfer (FET) cycles, endometrial thickness (EMT) has been used routinely as the main clinical monitoring index. However, the current findings are conflicting.

Method

This was a single-center retrospective study of 2,054 couples (2,562 cycles) who underwent FET (including cleavage stage embryos and blastocysts) between January 2017 and August 2020 in the reproductive centers of First Affiliated Hospital of Xinjiang Medical University. The primary outcome measure was the ongoing pregnancy rate (OPR); the secondary outcome was the clinical pregnancy rate.

Results

After stratified analysis and adjusting for confounders such as maternal age, duration of infertility, number of high-quality embryos transferred, endometrial preparation protocol, number of transfer cycles, and stages of embryo transferred, we found a curvilinear relationship between EMT and the OPR in women < 35 years of age. For women with EMT ≤ 8 mm, the OPR increased by 150% for cleavage stage embryo transfer for every 1 mm increase in the EMT; similarly, it increased by 97% for blastocyst stage FET. However, there was a linear relationship between EMT and OPR in women aged ≥ 35 years. When blastocysts were transferred, for every 1 mm increase in the EMT the OPR increased significantly by 12%. But OPR after frozen-thawed cleavage stage embryos transfer did not increase significantly with increased EMT.

Conclusions

Our study showed that the OPR increased significantly with increased EMT between young women aged < 35 years with EMT ≤ 8 mm and older women who underwent transfer of blastocysts.

Randomized controlled trial of astaxanthin impacts on antioxidant status and assisted reproductive technology outcomes in women with polycystic ovarian syndrome

PURPOSE

Polycystic ovary syndrome (PCOS), the most common endocrinopathy in women, is typically accompanied by a defective oxidative defense system. Here, we investigated the effect of astaxanthin (AST) as a powerful antioxidant on the oxidative stress (OS) response and assisted reproductive technology (ART) outcomes in PCOS patients.

METHODS

In this double-blind, randomized, placebo-controlled trial, PCOS patients were randomly assigned into two groups. The intervention group received 8 mg AST, and the control group received the placebo daily for 40 days. The primary outcomes were the serum and follicular fluid (FF) levels of the OS biomarkers and the expression levels of the specific genes and proteins in the oxidative stress response pathway. The secondary outcomes were considered ART outcomes.

RESULTS

According to our findings, a 40-day course of AST supplementation led to significantly higher levels of serum CAT and TAC in the AST group compared to the placebo group. However, there were no significant intergroup differences in the serum MDA and SOD levels, as well as the FF levels of OS markers. The expression of Nrf2, HO-1, and NQ-1 was significantly increased in the granulosa cells (GCs) of the AST group. Moreover, the MII oocyte and high-quality embryo rate were significantly increased in the AST group compared to the placebo group. We found no significant intergroup difference in the chemical and clinical pregnancy rates.

CONCLUSION

AST treatment has been shown to increase both serum TAC levels and activation of the Nrf2 axis in PCOS patients' GCs.

TRIAL REGISTRATION

ClincialTrials.gov Identifier: NCT03991286.

Comparison of Stimulated Cycles with Low Dose r-FSH versus Hormone Replacement Cycles for Endometrial Preparation Prior to Frozen-Thawed Embryo Transfer in Young Women with Polycystic Ovarian Syndrome: A Single-Center Retrospective Cohort Study from China

Objective

The principal purpose of this study was to compare reproductive outcomes for stimulated cycles (STC) and hormone replacement cycles (HRC) for endometrial preparation before frozen-thawed embryo transfer (FET) in young women with polycystic ovary syndrome (PCOS).

Methods

We conducted a retrospective study of 1434 FET cycles from January, 2017 to March, 2020 in our reproductive center, in which stimulated and hormone replacement cycles were used for endometrial preparation. Pregnancy outcomes of couples undergoing routine STC-FET or HRC-FET were analyzed by propensity score matching (PSM) and multivariable logistic regression analyses.

Results

Data on 1234 HRC protocols (86% of the total) and 200 STC protocols (14%) were collected. After PSM, 199 patients were included in both groups, respectively. There was no significant difference in positive pregnancy rate (52.7% vs 54.8%, p=0.763), clinical pregnancy rate (51.8% vs 52.8%, p=0.841), live birth rate (45.2% vs 43.7%, p=0.762), pregnancy loss rate (9.7% vs 16.2%, p=0.164) and ectopic pregnancy rate (1.5% vs 0.5%, p=0.615) between STC and HRC protocols. Subsequent multivariate logistic regression analysis also yielded similar results.

Conclusion

STC for endometrial preparation had similar pregnancy outcomes compared with HRC protocols. Evidence is available which shows that for young women with PCOS in preparation for FET, HRC could be a reasonable choice for patients who are unwilling to accept injections. However, STC may reduce unnecessary anxiety and operational costs and offer more flexibility for patients. Eventually, we must embrace the concepts of individualization, securitization, and optimization in the clinic.

The effect of endometrial thickness on live birth outcomes in women undergoing hormone-replaced frozen embryo transfer

Objective

To determine the impact of endometrial thickness on live birth outcomes and obstetric complication rate after hormone-replaced frozen embryo transfer.

Design

Retrospective cohort study.

Setting

Large, urban, academic fertility center.

Patients

All patients with a singleton live birth after single euploid embryo transfer (by array comparative genomic hybridization or next-generation sequencing) in a hormone-replaced frozen embryo transfer cycle between January 2017 and December 2018 were reviewed.

Interventions

None.

Main Outcome measures

The primary outcomes were birth weight and obstetric complication rate.

Results

A total of 492 patients were included. The median endometrial thickness was 8.60 mm (range, 6.0-20.0). The median gestational age at live birth was 39.4 weeks with a median birth weight of 3,345.2 g. Endometrial thickness was significantly correlated with birth weight. When patients were dichotomized into groups (those with an endometrial thickness of <7 mm and those with an endometrial thickness of >7 mm), neonates born from endometria with a thickness of <7 mm were born earlier (37.3 vs. 39.4 weeks and born with lower birth weights (2,749.9 vs. 3,345.2 g). It should be noted that only seven patients had an endometrium measuring <7 mm. Moreover, 7.1% (n = 35) of patients had an obstetric complication. Endometrial thickness was not significantly associated with obstetric complications, even with adjustments for age and medical history.

Conclusions

Endometrial thickness may be a valuable predictor of placental health and birth weight. Further study is required to examine the relationship with individual obstetric complications, as our study may not have been powered to observe differences in obstetric complication rate, as well as the relationship between endometrial thickness and outcomes in natural frozen embryo transfer cycles.