Frozen-thawed embryo transfer: the potential importance of the corpus luteum in preventing obstetrical complications

Pregnancy outcomes after frozen-thawed embryo transfer using letrozole ovulation induction, natural, or programmed cycles

OBJECTIVE

To evaluate and compare pregnancy outcomes between letrozole ovulation induction, natural, and programmed frozen-thawed embryo transfer (FET) cycles in a population based in the United States.

DESIGN

Retrospective cohort study.

SETTING

Single university-affiliated infertility practice.

PATIENT(S)

A total of 3,148 FET cycles consisting of patients aged ≤45 years transferring blastocysts that were created from autologous oocytes between January 2015 and July 2021.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The primary outcome was the ongoing pregnancy rate (OPR) or live birth rate (LBR). The secondary outcomes included clinical pregnancy and clinical loss rates (CLRs).

RESULT(S)

The OPR/LBR was higher among letrozole FETs than among programmed FETs (adjusted risk ratio [aRR] 1.11, 95% confidence interval [CI] 1.02-1.21) but comparable to natural FETs (aRR 1.05, 95% CI 0.96-1.14). The OPR/LBR was comparable between natural and programmed FETs (aRR 1.06, 95% CI 0.99-1.13). The CLR was lower in the natural FET group than in the programmed FET group (aRR 0.62, 95% CI 0.46-0.84). There were no differences in CLRs between letrozole and programmed FETs and between letrozole and natural FETs. Among ovulatory women, the OPR/LBR among letrozole FETs was higher than that among programmed FETs (aRR 1.16, 95% CI 1.05-1.28). The CLR among ovulatory women was significantly lower in both letrozole FETs (aRR 0.44, 95% CI 0.22-0.87) and natural FETs (aRR 0.59, 95% CI 0.43-0.80) than in programmed FETs. Among anovulatory women, the OPR/LBR in the letrozole FET group was similar to that in the programmed FET group (aRR 0.95, 95% CI 0.79-1.13).

CONCLUSION(S)

Letrozole and natural FET clinical outcomes were improved compared with programmed FET outcomes.

Neutrophil-to-lymphocyte ratio is a predictor of biochemical miscarriage following artificial frozen embryo transfer cycles

The aim of this study is to examine the relationship between complete blood count (CBC) inflammatory markers and pregnancy outcome following artificial frozen embryo transfer cycles (AC-FET). This was a retrospective cohort study including 183 patients undergoing an AC-FET. The inflammatory markers including white blood cell count (WCC), neutrophil and lymphocyte count, neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were compared between cycles with and without clinical pregnancies. Furthermore, these markers were compared between pregnancies with and without biochemical and clinical miscarriages. NLR was significantly higher in cycles with biochemical miscarriages (p = 0.009). Receiver operating curve analysis was performed to assess the role of NLR in predicting biochemical pregnancy. The area under the curve was 0.714 (95% confidence interval; 0.578-0.850, p = 0.009). The optimal cut-off value for NLR that was associated with biochemical miscarriage was 2.48 with 63% sensitivity and 75% specificity. A logistic regression analysis was performed with biochemical miscarriage as the dependent variable. An NLR value below 2.48 was an independent variable to affect biochemical miscarriage (OR: 0.2, 95% CI 0.05-0.92, p = 0.030). NLR emerged as a reliable predictor of biochemical miscarriage in AC-FET.Impact StatementWhat is already known on this subject? NLR and PLR are novel markers of inflammation. They are related to various gynecological and obstetric conditions including spontaneous abortion, preeclampsia. These markers are also associated with assisted reproductive technology success in fresh cycles.What the results of this study add? This is the first study to investigate the association of these markers with FET cycles. Our results have shown that cycles that ended in biochemical miscarriage had a significantly higher NLR compared with cycles continuing as a clinical pregnancy. An NLR value above 2.48 was predictive of biochemical miscarriage following AC-FET.What the implications are of these findings for clinical practice and/or further research? A high NLR level might have a significant value for the identification of patients at risk of biochemical miscarriage. Future research should assess the impact of anti-inflammatory agents on pregnancy outcomes in patient populations where systemic inflammation is documented by CBC inflammatory markers.

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.

An integrative approach to uncover the components, mechanisms, and functions of traditional Chinese medicine prescriptions on male infertility

Male infertility is a major and growing health problem with an estimated global prevalence of 4.2%. The current therapy is limited by the unknown etiology of MI, emphasizing the critical requirement forward to a more efficient method or medication. Through thousands of years, Traditional Chinese Medicine (TCM) has been shown to be effective in treating MI effectively. However, the components, mechanisms and functions of TCM prescriptions on MI are still obscure, severely limiting its clinical application. In order to discover the molecular mechanism of TCM against MI, our study presents a comprehensive approach integrated data mining, network pharmacology, molecular docking, UHPLC-Q-Orbitrap HRMS, and experimental validation. Here, we begin to acquire 289 clinical TCM prescriptions for MI from a TCM hospital’s outpatient department. Then, Core Chinese Materia Medica (CCMM) was then retrieved from the TCM Inheritance Support System (TCMISS), which was utilized to discover the underlying rules and connections in clinical prescriptions. After that, 98 CCMM components and 816 MI targets were obtained from ten distinct databases. Additionally, the network pharmacology methods, including network construction, GO and KEGG pathway enrichment, PPI analysis, were utilized to reveal that kaempferol, quercetin, isorhamnetin, and beta-sitosterol are the core components of CCMM in treating MI. The mechanisms and functions of CCMM against MI are hormone regulation, anti-apoptosis, anti-oxidant stress, and anti-inflammatory. Furthermore, the strong connections between four core components and six key targets were verified using a molecular docking method. Following that, the core components of the CCMM extract were identified using UHPLC-Q-Orbitrap HRMS analysis. Finally, in vivo experiments demonstrated that CCMM and four core components could improve the density, motility, viability of sperm, lecithin corpuscle density, decrease the rate of sperm malformation and testis tissue damage, and regulate the protein expressions of AKT1, MAPK3/1, EGFR, and TNF-α in a mouse model of MI. UHPLC-Q-Orbitrap HRMS analysis and in vivo experiments further validated the results of data mining, network pharmacology, and molecular docking. Our study could uncover the components, mechanisms, and functions of TCM prescriptions against MI and develop a new integrative approach to demonstrate TCM’s multi-component, multi-target, and multi-pathway approach to disease treatment.

Endometrial thickness is an independent risk factor of hypertensive disorders of pregnancy: a retrospective study of 13,458 patients in frozen-thawed embryo transfers

BACKGROUND

Hypertensive disorders of pregnancy (HDP) are an important cause of maternal and fetal mortality, and its potential risk factors are still being explored. Endometrial thickness (EMT), as one of the important monitoring indicators of endometrial receptivity, has been confirmed to be related to the incidence of HDP in fresh embryo transfer. Our study was designed to investigate whether endometrial thickness is associated with the risk of hypertensive disorders of pregnancy in frozen-thawed embryo transfer (FET).

METHODS

This respective cohort study enrolled 13,458 women who received vitrified embryo transfer and had a singleton delivery in the Reproductive Hospital affiliated to Shandong University from January 2015 to December 2019. We set strict screening criteria and obtained the information from the hospital electronic medical system. Statistical methods including logistic regression analysis, receiver operating characteristic curve and restricted cubic spline were used to evaluate the relationship between endometrial thickness and the incidence of pregnancy-induced hypertension.

RESULTS

The incidences of HDP in a thin endometrial thickness group (< 0.8 cm) and a thick endometrial thickness group (> 1.2 cm) were significantly greater than in a reference group (0.8 cm-1.2 cm) (7.98 and 5.24% vs 4.59%, P <  0.001). A nonlinear relationship between endometrial thickness and risk of hypertensive disorders of pregnancy was examined by restricted cubic spline (P <  0.001). The thin endometrial thickness and thick endometrial thickness groups were significantly associated with the risk of HDP after adjusting for confounding variables by stepwise logistic regression analysis. Subsequently, subgroup logistic regression analysis based on endometrial preparation regimens showed that thin endometria were still significantly associated with a higher morbidity rate in the artificial cycle group, while in the natural cycle group, thick endometria were closely associated with increased morbidity.

CONCLUSION

Our study manifested that both the thin and thick endometria were associated with an increased risk of hypertensive disorders of pregnancy in frozen embryo transfer cycles. Reproductive clinicians should focus on adjusting endometrial thickness in different preparation regimens; and obstetricians should be mindful of the risk of hypertension during pregnancy, when women with thin (< 0.8 cm) or excessively thicker (> 1.2 cm) endometrial thickness achieve pregnancy through frozen-thawed embryo transfer.

Facilitators and barriers for home-based monitoring to time frozen embryo transfers in IVF among women and healthcare providers

STUDY QUESTION

What are the facilitators and barriers concerning the implementation of home-based monitoring for natural cycle frozen embryo transfer (NC-FET) from the perspectives of patients and healthcare providers in the Netherlands?

SUMMARY ANSWER

The most important facilitator was optimal pregnancy chance for both the patients and healthcare providers, and the most important barriers were the risk of missing an ovulation for the patients and laboratory capacity for the healthcare providers.

WHAT IS KNOWN ALREADY

The share of FET cycles in IVF treatments is increasing and, therefore, it is important to optimize protocols for FET. Monitoring of ovulation, which is used in NC-FET, can be hospital-based (ultrasounds and ovulation triggering) or home-based (LH urine tests). Home-based monitoring has the advantage of being the most natural protocol for FET and provides the feeling of empowerment and discretion for patients. A systematic approach for the implementation of home-based monitoring has to start with an exploration of the perspectives of all stakeholders.

STUDY DESIGN, SIZE, DURATION

Stakeholders (patients and healthcare providers) involved in the implementation process in the Netherlands participated in the present study. Patients were represented by the Dutch Patient Organisation for Couples with Fertility Problems (FREYA) and healthcare providers were represented by gynaecologists and their society (The Netherlands Society of Obstetrics and Gynaecology), embryologists and their society (The Dutch Federation of Clinical Embryology) as well as fertility doctors. A panel of experts hypothesized on barriers and facilitators for the implementation of home-based monitoring during the proposal phase of the Antarctica-2 randomized controlled trial (RCT).

PARTICIPANTS/MATERIALS, SETTING, METHODS

All stakeholders were represented during the study. Two different questionnaires were developed in order to investigate facilitators and barriers for the patients and for healthcare providers. The facilitators and barriers were ranked on a scale of 1–10 with 10 being the most important. Based on our power analysis, we aimed for a minimum of 300 completed questionnaires for the patients and a minimum of 90 completed questionnaires for the healthcare providers. Facilitators and barriers were analysed using frequencies, mean (SD) and ranking.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 311 patients filled out the questionnaire of whom 86.8% underwent FET previously. The most important facilitator for the patients was to implement the strategy with the highest chance of pregnancy (mean 9.7; 95% CI 9.6–9.7) and the most important barrier was risk of missing ovulation (mean 8.4; 95% CI 8.2–8.6). A total of 96 healthcare providers filled out the questionnaire. According to healthcare providers, patients would accept the strategy when it causes less interference with their work and private life (mean 7.5; 95% CI 7.1–8.0) and has a low risk of missing the ovulation (mean 7.6; 95% CI 7.1–8.0). The most important facilitator for the implementation of home-based monitoring for healthcare providers was optimizing cumulative pregnancy rates (mean 8.1; 95% CI 7.7–8.4) and the most important barrier was the lack of laboratory capacity and flexibility (mean 6.4; 95% CI 5.8–7.0).

LIMITATIONS, REASONS FOR CAUTION

Facilitators and barriers were selected based on expert opinion. Currently, there are no validated questionnaires that aim to assess facilitators and barriers for the implementation of treatments in fertility care.

WIDER IMPLICATIONS OF THE FINDINGS

During our study, we gained insight into barriers and facilitators for the implementation of home-based monitoring of NC-FET at an early phase. Early sharing and discussion of the results of this study with all stakeholders involved should stimulate a fast incorporation in guidelines, especially as key professionals in guideline development took part in this study. Also, based on our results, we can advise guideline developers to add tools to the guideline that may help overcome the implementation barriers.

STUDY FUNDING/COMPETING INTERESTS

The Antarctica-2 RCT is supported by a grant from the Netherlands Organisation for Health Research and Development (ZonMw 843002807). No authors have any competing interests to declare.

TRIAL REGISTRATION NUMBER

Trial NL6414 (NTR6590).

Analysis of Relevant Factors Affecting the Pregnancy Rate of Frozen-Thawed Embryo Transfer Cycle

Objective

The aim of this study is to explore the relevant factors affecting the pregnancy rate of frozen-thawed embryo transfer cycle.

Methods

The clinical data of 931 patients who underwent artificial cycle preparation for endometrial FET from April 2017 to November 2020 in the reproductive center of our hospital were retrospectively analyzed.

Results

According to the pregnancy situation, the patients were divided into 450 cases of pregnancy and 481 cases of biochemical pregnancy. The univariate analysis of FET biochemical pregnancy showed that there were statistically significant differences between pregnancy and biochemical pregnancy in terms of years of infertility, age, endometrial thickness, P level, E2/P, and the number of high-quality embryos (P < 0.05). Multivariate analysis of pregnancy showed that age <30 years was a protective factor for biochemical pregnancy and endometrial thickness <8 mm and E2/P < 0.3 were risk factors (P < 0.05).

Conclusion

The regulation of endometrial thickness and E2/P serves as the key of treatment for patients undergoing FET using artificial cycle preparation for endometrial transfer, and it contributes to improve the pregnancy rate; also, the patient's age is an important indicator influencing the pregnancy rate.

Alteration of LncRNA expression in mice placentae after frozen embryo transfer is associated with increased fetal weight

The birthweight after frozen embryo transfer (FET) was significantly higher compared with fresh embryo transfer (fresh ET), while the mechanism remains unclear. In this study, we transferred vitrified-warmed or fresh mice blastocysts into pseudopregnant recipients (n = 11 each group) produced by natural mating to avoid the influence of superovulation. The fetal weight, placental weight, placental efficiency and placental architecture were studied at E18.5. Placental RNA-Seq analysis was used to identify candidate different lncRNAs and mRNAs between the FET group and the fresh ET group. We found that the fetal weight was increased in the FET group, with increased placental efficiency and the proportion of placental function related labyrinth zone area. 554 lncRNAs and 1012 mRNAs were differentially expressed. KEGG and GO enrichment analyses showed these differentially expressed lncRNAs and their targeted mRNAs might be related to placental morphogenesis. Furthermore, the most differentially expressed 15 lncRNAs and 15 mRNAs were validated by qRT-PCR, we found the LncRNA embryonic stem cells expressed 1 (Lncenc1) was significantly decreased, and Gjb5, which played an important role in labyrinth zone development, was increased. Gjb5 protein increase was further confirmed by Western blot. Lncenc1 and Gjb5 had 48 predicted co-targeted miRNAs, while the correlation analysis of Lncenc1 and Gjb5 mRNA showed a significant inverse correlation. The results showed that FET treatment might enhance the placental function to increase mouse fetal weight via the network diagram of Lncenc1-miRNA-Gjb5.

Adverse obstetric and perinatal outcomes in 2333 singleton pregnancies conceived after different endometrial preparation protocols: a retrospective study in China

BACKGROUP

Frozen-thawed embryo transfer is rising worldwide. One adverse effect of programmed frozen embryo transfer (FET) reported in some studies is an increased risk of adverse obstetric and perinatal outcomes. Meanwhile, body mass index (BMI) also has adverse effect on obstetric and perinatal outcomes. In this study, we investigated that the influence of different endometrial preparation protocols on obstetric and perinatal outcomes and the role of BMI in it.

METHOD

This retrospective cohort study included 2333 singleton deliveries after frozen-thaw embryo transfer at our centre between 2014 and 2021, including 550 cycles with programmed FET, 1783 cycles with true natural cycle FET (tNC-FET). In further analysis according to BMI grouped by Asian criterion, group A (18.5 kg/m² ≤ BMI < 24.00 kg/m²) included 1257 subjects, group B (24 kg/m² ≤ BMI < 28.00 kg/m²) included 503 subjects and group C (BMI ≥ 28 kg/m²) included 573 subjects. Baseline characteristics of the two groups were compared and analyzed. Binary logistic regression analyses were performed to explore the association between obstetric and perinatal outcomes and endometrial preparation protocols.

RESULTS

There were no significant differences in the placenta previa, gestational diabetes mellitus(GDM), preterm premature rupture of membranes (PPROM), cesarean section (CS) and macrosomia between the tNC-FET and programmed FET groups (P > 0.05). The programmed FET cycles were associated to a higher risk of pregnancy-induced hypertension (PIH) compared with the tNC-FET cycles (7.3% vs 4.4%, crude OR 1.71[1.16-2.54]; adjusted OR 1.845[1.03-3.30]). After dividing the patients into three groups according to the BMI, The programmed FET cycles were associated to a higher risk of PIH in group C (14.4% vs 6.2%, crude OR 2.55 [1.42-4.55]; adjusted OR 4.71 [1.77-12.55]) compared with the tNC-FET cycles. But there was no statistically significant difference in group A and group B. Programmed FET group compared with the tNC-FET group, the risk of PIH increase as the body mass index increase.

CONCLUSION

This study showed a tendency toward increasing risk of PIH in programmed FET cycle compared with the tNC-FET cycle, and the risk of PIH increases as BMI increases. Increased risk of preterm birth and low birth weight is linked to increased risk of PIH.

Granulocyte-macrophage colony-stimulating factor-containing medium treatment after thawing improves blastocyst-transfer outcomes in the frozen- thawed blastocyst-transfer cycle

PURPOSE

To determine whether granulocyte-macrophage colony-stimulating factor (GM-CSF)-containing medium could improve embryo-transfer outcomes in frozen-thawed blastocyst transfer.

METHODS

Patients who underwent frozen-thawed blastocyst transfer (430 women, aged 30-39 years, 566 cycles) were analyzed. Frozen-thawed blastocysts were cultured in GM-CSF-containing medium or control medium for 3-5 h, followed by transfer to the uterus. The embryo-transfer outcomes in the two groups were measured and compared, and a propensity score matching (1:1) method was used to balance the differences in baseline characteristics. We analyzed 213 matched samples.

RESULTS

In patients who underwent frozen-thawed blastocyst transfer with GM-CSF, the percentage of human chorionic gonadotropin-positive cases, biochemical pregnancies, clinical pregnancies, ongoing pregnancies, and live birth rates was 60.6%, 7.98%, 52.6%, 42.9%, and 40.9%, respectively, as compared with 45.1%, 3.29%, 41.8%, 31.1%, and 30.5%, respectively, for the control groups. The rates of human chorionic gonadotropin positivity (odds ratio [OR]: 1.87, 95% confidence interval: [CI]: 1.27-2.75), biochemical pregnancy (2.55, 1.04-6.29), clinical pregnancy (1.54, 1.05-2.27), ongoing pregnancy (1.64, 1.13-2.41), and live birth (1.67, 1.14-2.45) were significantly higher in the GM-CSF group than the control group. The incidence of pregnancy loss (22.3% vs. 27.0%) did not significantly differ between the groups.

CONCLUSION

The use of a GM-CSF-containing medium for blastocyst-recovery culture improved the live birth rate as a result of increased implantation rate in the frozen-thawed blastocyst-transfer cycle. The use of GM-CSF-containing medium following blastocyst thawing could be an effective choice for improving the blastocyst-transfer outcomes.

Endometriosis does not seem to be an influencing factor of hypertensive disorders of pregnancy in IVF / ICSI cycles

INTRODUCTION

To evaluate whether the incidence of hypertensive disorders of pregnancy (HDP) in pregnant women was related to endometriosis (EM), ovulation and embryo vitrification technology.

METHODS

A retrospective cohort study was conducted on the clinical data of 3674 women who were treated with IVF / ICSI in the Reproductive Medicine Center of the First Affiliated Hospital of Sun Yat-sen University and maintained clinical pregnancy for more than 20 weeks. All pregnancies were followed up until the end of pregnancy. The follow-up consisted of recording the course of pregnancy, pregnancy complications, and basic situation of newborns.

RESULTS

Compared with NC-FET without EM, HRT-FET without EM was found to have a higher incidence of HDP during pregnancy (2.7% V.S. 6.1%, P<0.001); however, no significant difference was found in the incidence of HDP between NC-FET and HRT-FET combined with EM (4.0% V.S. 5.7%, P>0.05). In total frozen-thawed embryo transfer (total-FET), the incidence of HDP in the HRT cycle without ovulation (HRT-FET) was observed to be higher than that in the NC cycle with ovulation (NC-FET) (2.8% V.S. 6.1%, P<0.001). In patients with EM, no significant difference was found in the incidence of HDP between fresh ET and NC-FET (1.2% V.S. 4.0%, P>0.05).

CONCLUSION

EM does not seem to have an effect on the occurrence of HDP in assisted reproductive technology. During the FET cycle, the formation of the corpus luteum may play a protective role in the occurrence and development of HDP. Potential damage to the embryo caused by cryopreservation seems to have no effect on the occurrence of HDP.

Natural cycles achieve better pregnancy outcomes than artificial cycles in non-PCOS women undergoing vitrified single-blastocyst transfer: a retrospective cohort study of 6840 cycles

PURPOSE

To identify the optimal method for endometrial preparation in vitrified single-blastocyst transfer (VSBT) cycles.

METHODS

This was a retrospective cohort study for non-PCOS patients who underwent VSBT cycles from March 2015 to November 2019 in an academic reproductive medical center. A total of 6840 VSBT cycles were enrolled and classified into two groups according to different endometrial preparation methods.

RESULTS

The non-PCOS patients who underwent VSBT showed a significantly higher clinical pregnancy rate (61.96% vs 56.85%, p < 0.001) and live birth rate (49.09% vs 39.86%, p < 0.001), as well as a statistically lower early miscarriage rate (12.02% vs 18.08%, p < 0.001) in the natural cycle (NC) group compared with the artificial cycle (AC) group. Multivariable analysis further confirmed that NC was associated with an increased likelihood of clinical pregnancy (adjusted odds ratio (aOR) 0.852, 95% confidence interval (CI) 0.765-0.949, p = 0.004) and live birth (aOR 0.746, 95% CI 0.669-0.832, p < 0 .001), but decreased early miscarriage occurrence (aOR 1.447, 95% CI 1.215-1.724, p < 0.001) compared to AC.

CONCLUSIONS

Our study demonstrated that non-PCOS patients could benefit from NC in vitrified blastocyst transfer. Increased clinical pregnancy rate and decreased early miscarriage rate led to a significantly higher live birth rate in NC patients compared with AC with our present protocol.

Preconception ovarian reserve and placenta-mediated pregnancy complications among infertile women

RESEARCH QUESTION

Are preconception ovarian reserve markers, such as Anti-Mullerian hormone and antral follicle count, associated with preeclampsia and placenta mediated pregnancy complications among women with unexplained infertility who conceive with superovulation?

DESIGN

This is a secondary analysis of women with unexplained infertility who had a singleton live birth after enrollment in the Analysis of Multiple Intrauterine Gestations after Ovarian Stimulation (AMIGOS) trial that randomized couples to superovulation with letrozole, clomiphene, or gonadotropins with insemination for up to 4 cycles.

RESULTS

Compared to controls (N = 156), women who developed preeclampsia (N = 17) had lower Anti-Mullerian hormone levels (2.24 ± 1.20 vs. 2.89 ± 2.32, p = 0.07) and lower antral follicle count (18 ± 7.67 vs. 21 ± 11.43, p = 0.16); though these differences were not statistically significant. There was no relationship between Anti-Mullerian hormone (OR: 1.00, 95% CI: 0.76-1.25) or antral follicle count (OR: 0.98, 95% CI 0.93-1.04) with preeclampsia and between Anti-Mullerian hormone (OR: 1.00, 95% CI: 0.83-1.17) and antral follicle count (OR: 1.00, 95% CI: 0.97-1.04) with placenta medicated pregnancy complications after adjusting for age, BMI and race.

CONCLUSIONS

Preconception ovarian reserve markers are not associated with preeclampsia and placenta mediated pregnancy complications among women with unexplained infertility who conceive with superovulation with insemination.

The impact of different cycle regimens on birthweight of singletons in frozen-thawed embryo transfer cycles of ovulatory women

OBJECTIVE

To investigate whether different endometrial preparation regimens affect neonatal outcomes after frozen-thawed embryo transfer (FET).

DESIGN

Retrospective cohort study.

SETTING

Tertiary care academic medical center.

PATIENTS

A total of 3,639 patients with live-born singletons were categorized into three groups on the basis of the type of endometrial preparation regimens. Of these, 1,225, 2,136, and 278 live-born singletons were conceived through natural cycle FET, artificial cycle FET, and stimulated cycle FET, respectively.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURES

The main outcomes were the measures of birthweight including the absolute mean birthweight, Z-score, low birthweight, high birthweight (HBW), small for gestational age, and large for gestational age (LGA).

RESULTS

After controlling for a variety of covariates, singletons from the artificial cycle FET group had a higher mean birthweight and Z-score than those from the natural cycle FET group and stimulated cycle FET group. The risk of LGA infants significantly increased in the artificial cycle group (14.0%) than that in the natural cycle group (10.3%) and stimulated cycle group (7.6%). The risk of hypertensive disorders of pregnancy in the artificial cycle group (4.4%) was significantly higher than that in the natural cycle group (2.5%). The stimulated cycle FET singletons had a higher risk of low birthweight than the natural cycle FET singletons. The other perinatal outcomes, including the incidence of preterm birth, small for gestational age, and gestational diabetes mellitus, were comparable between the groups before or after adjustment for confounders.

CONCLUSIONS

Singletons from artificial cycle FET were associated with a higher risk of LGA infants, and natural cycle FET may be a better regimen for ovulatory women. Our results indicate a link between the absence of the corpus luteum and adverse perinatal outcomes, and further studies are needed to detect the underlying mechanism.

Perinatal outcomes of singleton live births after preimplantation genetic testing during single frozen-thawed blastocyst transfer cycles: a propensity score-matched study

OBJECTIVE

To determine whether singleton pregnancy achieved after preimplantation genetic testing (PGT) is associated with a higher risk of adverse perinatal outcomes than in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) singleton pregnancy.

DESIGN

A retrospective cohort study.

SETTING

A university-affiliated fertility center.

PATIENT(S)

This cohort study included singleton live births resulting from PGT (n = 232) and IVF/ICSI singleton pregnancies (n = 2,829) with single frozen-thawed blastocyst transfer. Multiple baseline covariates were used for propensity score matching, yielding 214 PGT singleton pregnancies matched to 617 IVF/ICSI singleton pregnancies.

INTERVENTION(S)

Trophectoderm biopsy.

MAIN OUTCOME MEASURE(S)

The primary outcome was gestational hypertension, and various clinical perinatal secondary outcomes related to maternal and neonatal health were measured.

RESULT(S)

Compared with IVF/ICSI singleton pregnancy, PGT singleton pregnancy was associated with a significantly higher risk of gestational hypertension (adjusted odds ratio, 2.58; 95% confidence interval, 1.32, 5.05). In the matched sample, the risk of gestational hypertension remained higher with PGT singleton pregnancy (odds ratio, 2.33; 95% confidence interval, 1.04, 5.22) than with IVF/ICSI singleton pregnancy. No statistical differences were noted in any other measured outcomes between the groups.

CONCLUSION(S)

The perinatal outcomes of PGT and IVF/ICSI singleton pregnancies were similar except for the observed potentially higher risk of gestational hypertension with PGT singleton pregnancy. However, because the data on PGT singleton pregnancies are limited, this conclusion warrants further investigation.

Comparison of Perinatal Outcomes of Letrozole-Induced Ovulation and Hormone Replacement Therapy Protocols in Patients With Abnormal Ovulation Undergoing Frozen-Thawed Embryo Transfer: A Propensity Score Matching Analysis

BACKGROUND

With the increasing use of frozen embryo transfer (FET), the best endometrial preparation protocol is continuously being discussed. The hormone replacement therapy (HRT) cycle and letrozole-induced ovulation (L-OI) cycle are available protocols for patients with abnormal ovulation. Previous comparisons of the two protocols have focused on pregnancy outcomes, with less attention to perinatal outcomes, and population heterogeneity was large; thus, convincing conclusions about which protocol is more appropriate could not be drawn.

METHODS

We performed a retrospective cohort study using propensity score matching (PSM) analysis for a population of patients undergoing FET cycles in the reproductive center of the Third Affiliated Hospital of Zhengzhou University from January 2016 to September 2020. The main outcome measures were clinical pregnancy rate, live birth rate, very preterm delivery (VPTD), preterm delivery (PTD), low birth weight (LBW), macrosomia, small for gestational age (SGA), large for gestational age (LGA), hypertensive disorders of pregnancy (HDP), gestational diabetes mellitus (GDM), premature rupture of membranes (PROM), placenta previa, and congenital abnormality.

RESULTS

A total of 8010 women were enrolled. Due to the large heterogeneity among the patients, we conducted 1:1 PSM, and 1461 women matched in each group. Compared with the HRT group, the L-OI group had a smaller proportion of thin endometrium (27.38% vs. 41.07%) and thicker endometrium on the day of embryo transfer (9.63 ± 1.82 vs. 8.91 ± 1.38). There were no significant differences in clinical pregnancy rate, early abortion rate or live birth rate between the groups. There was no significant difference in perinatal outcomes of singleton live birth, including VPTD, PTD, postterm delivery, LBW, macrosomia, SGA, LGA, GDM, HDP, placenta previa, and congenital malformation.

CONCLUSION

For women with abnormal ovulation, the pregnancy and perinatal outcomes of HRT and L-OI protocols are reassuring. It seems that both protocols are safe and effective for endometrial preparation in frozen-thawed embryo transfer in the clinic.

Optimal waiting period for frozen embryo transfer after hysteroscopic polypectomy: A propensity score matching analysis

OBJECTIVE

To evaluate the optimal waiting period for frozen-thawed embryo transfer (FET) after hysteroscopic polypectomy (HSC-P).

DESIGN

Retrospective cohort.

SETTING

University-affiliated hospital.

PATIENTS

All patients included in this research underwent hysteroscopy before the first FET cycle after whole embryo freezing. A total of 206 patients had undergone HSC-P, and 3681 patients without endometrial polyps were defined as the controls.

INTERVENTIONS

HSC-P.

MAIN OUTCOME MEASURES

The HSC-P group was divided into three subgroups based on the time interval between HSC-P and the start of an FET cycle. Subgroup 1 consisted of patients who underwent FET after their next menses, subgroup 2 after two menstrual cycles, and subgroup 3 after three or more menstrual cycles. Demographics, baseline in vitro fertilization (IVF) characteristics, and pregnancy outcomes, especially perinatal outcomes after FET were compared among the groups.

RESULTS

There were 137 patients in subgroup 1, 40 in subgroup 2, and 29 in subgroup 3. There were no differences in the baseline characteristics of the three groups. IVF-related data and FET-related data, such as endometrial thickness and ET no. Of embryoes, were similar among the three subgroups. The three subgroups showed no significant differences in implantation rate, biochemical pregnancy rate, abortion rate, clinical pregnancy rate or live birth rate. Besides, There was no significant difference in perinatal outcomes including very preterm delivery, preterm delivery, low birth weight, macrosomia, small for gestational age, large for gestational age, birth weight(g), birth-height(cm)and Apgar Scores.

CONCLUSIONS

Compared with FET after their next menses, FET after two or more menstrual cycles after HSC-P does not necessarily produce superior outcomes.

Effects of different frozen embryo transfer regimens on abnormalities of fetal weight: a systematic review and meta-analysis

BACKGROUND

Reported increases in maternal and perinatal morbidity (including macrosomia, large for gestational age (LGA), cesarean section, hemorrhage and hypertensive disorders of pregnancy) following frozen embryo transfer (FET) cycles may be associated with the lack of a corpus luteum seen in programmed FET. Given the growing number of studies comparing outcomes between natural FET and programmed FET cycles, a meta-analysis would prove useful to detect the presence of abnormalities in fetal birth weight in patients undergoing natural and programmed FET cycles.

OBJECTIVE AND RATIONALE

The aim of this study was to provide a systematic review and meta-analysis of the effects of natural versus programmed methods of endometrial preparation for FET cycles on fetal weight and the risks of LGA and macrosomia.

SEARCH METHODS

A literature search using MEDLINE, SCOPUS, EMBASE and clinicaltrials.gov was conducted for published research comparing neonatal outcomes in natural FET and programmed FET cycles. Primary outcomes of interest were fetal weight, macrosomia and LGA. Studies were included if the following criteria were met: study contained cohorts of NFET and programmed FET with outcome data of birth weight, large for gestational data and/or macrosomia. The data are presented as average weight and odds ratio (OR) with 95% confidence interval (CI) with fixed- or random-effects meta-analysis between cohorts of NFET and programmed FET cycles. Bias was assessed using Newcastle-Ottawa quality assessment scale for the 14 included studies. Multiple subgroup analyses were performed to assess for effect of the true natural cycle (defined as no ovulation trigger medication use) and the day of embryo transfer on fetal weight parameters compared with programmed cycle FET.

OUTCOMES

A total of 879 studies were identified, with 15 meeting inclusion the criteria. The studies varied with respect to country of origin, definition of natural cycle FET and type of progesterone supplementation used. The included studies had similar gestational ages at the time of birth. Programmed FET cycles resulted in a higher fetal weight compared with natural FET cycles (mean difference 47.38 gp = 0.04). Programmed FET cycles were also at higher risk for macrosomia (OR 1.15, 95% CI 1.06-1.26) and LGA (OR 1.10, 95% CI 1.02-1.19) compared with natural FET cycles. Subgroup analyses demonstrated that programmed FET cycles resulted in a higher fetal weight compared with true natural FET (mean difference 62.18 gp = 0.0001) cycles. Cleavage stage embryo transfers had an increased risk of LGA (OR 1.27, 95% CI 1.00-1.62) and an increased risk of macrosomia (OR 1.25, 95% CI 1.08-1.44) in programmed FET cycles compared with natural FET cycles. Blastocyst transfer in programmed FET cycles resulted in no difference in risk of macrosomia but an increased risk of LGA (OR 1.13, 95% CI 1.06-1.21) compared with natural FET cycles.

WIDER IMPLICATIONS

Programmed endometrial preparation for FET cycles had a significant effect, causing increased fetal birth weight and increased risks of LGA and macrosomia. The numbers of studies in the subgroup analyses were too low to determine reliable results. Further prospective randomized trials are needed to determine whether the changes seen in the observational trials are indeed accurate.

Pregnancy Outcomes After Frozen-Thawed Embryo Transfer in the Absence of a Corpus Luteum

Background: Nowadays, frozen-thawed embryo transfer (FET) cycles represent a high proportion of fertility treatments worldwide. Recent studies suggest differences in pregnancy outcomes depending on the FET treatment protocol used. The reason for this is still unclear, but the number of corpora lutea (CL) at conception is discussed as a possible factor. This study aims to investigate whether maternal and neonatal outcomes for pregnancies following FET lacking a CL differ from FET with one or more CL in order to explore a potential link between CL absence and adverse pregnancy outcomes.

Methods: The study was designed as a retrospective, multi-center observational study with two cohorts after singleton live birth [0 CL cohort (FET in a programmed cycle, n = 114) and ≥ 1 CL cohort (FET in a natural or stimulated cycle, n = 68)]. Participants completed a questionnaire on the outcome of pregnancy and birth records were analyzed in a descriptive way. Multivariable logistic and linear regressions were performed in order to explore associations between CL absence and pregnancy outcomes. The strength of the agreement between the information in the survey and the diagnoses extracted from the files was assessed by Cohen's Kappa.

Results: The risk of hypertensive disorders of pregnancy was higher after FET in the absence of a CL compared to FET with CL presence (aOR 5.56, 95% CI 1.12 – 27.72). Birthweights and birthweight percentiles were significantly higher in the 0 CL group. CL absence was a predictor of higher birthweight (adjusted coefficient B 179.74, 95% CI 13.03 – 346.44) and higher birthweight percentiles (adjusted coefficient B 10.23, 95%, 95% CI 2.28 – 18.40) particularly in female newborns of the 0 CL cohort. While the strength of the agreement between the reported information in the survey and the actual diagnoses extracted from the files was good for the majority of outcomes of interest it was fair in terms of hypertension (κ = 0.38).

Conclusion: This study supports observations suggesting a potential link between a lack of CL at conception and adverse maternal and neonatal outcomes. Further investigations on causes and pathophysiological relationships are yet to be conducted.

Live birth rates after natural cycle versus hormone replacement therapy for single euploid blastocyst transfers: a retrospective cohort study

RESEARCH QUESTION

Is there any difference in live birth rate between the natural cycle and hormone replacement therapy (HRT) endometrial preparation protocols for women with regular menstrual cycles undergoing their first single vitrified-warmed euploid blastocyst transfer?

DESIGN

This was a retrospective cohort study that enrolled 722 women who underwent vitrified-warmed euploid blastocyst transfer at assisted reproductive technology (ART) centre of The First Affiliated Hospital of Zhengzhou University, from January 2013 to December 2019. Univariate and multivariate logistic regression models were used to analyse the relationship between the endometrial preparation protocols and live birth rates. Stratified analyses and sensitivity analyses were performed to ensure the reliability and stability of the results.

RESULTS

A total of 722 single vitrified-warmed euploid blastocyst transfer cycles were included. Overall, the live birth rates were 50.00% (110/220) in the natural cycle group and 47.61% (239/502) in the HRT group. Multiple logistic regression analyses showed that there was no significant association (adjusted odds ratio 0.82; 95% confidence interval 0.56-1.20; P = 0.313) between natural cycle and HRT protocols and the live birth rate. Interaction analysis showed that there was no significant difference in live birth rates between the two groups for any subgroup after adjusting for confounding factors.

CONCLUSIONS

For single vitrified-warmed euploid blastocyst transfer, natural cycle and HRT endometrial preparation protocols result in similar live birth rates among women with regular menstrual cycles. Further studies are needed into the effects of endometrial preparation protocols on pregnancy outcomes.

Obstetric and Perinatal Complications Associated with Assisted Reproductive Techniques - Review

Recently, the use of assisted reproductive techniques (ART) has witnessed a significant increase worldwide. Although most of these pregnancies have a good prognosis, studies show that ART is associated with a risk of obstetric and perinatal complications, compared to pregnancies conceived spontaneously. It is considered that the risk is directly proportional to the number of transferred embryos, thus multiple pregnancies are an independent risk factor that supports the large-scale implementation of single embryo transfer protocols. Simultaneously, studies report obstetric and perinatal complications in singleton pregnancies obtained after ART and it is not possible to establish whether parental or procedural factors are the causal determinants. The purpose of this article is to summarize the risk of maternal-fetal complications associated with ART.

Serum luteal phase progesterone in women undergoing frozen embryo transfer in assisted conception: a systematic review and meta-analysis

OBJECTIVE

To investigate the association between luteal serum progesterone levels and frozen embryo transfer (FET) outcomes.

DESIGN

Systematic review and meta-analysis.

SETTING

Not applicable.

PATIENT(S)

Women undergoing FET.

INTERVENTION(S)

We conducted electronic searches of MEDLINE, PubMed, CINAHL, EMBASE, the Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Web of Science, ClinicalTrials.gov, and grey literature (not widely available) from inception to March 2021 to identify cohort studies in which the serum luteal progesterone level was measured around the time of FET.

MAIN OUTCOME MEASURE(S)

Ongoing pregnancy or live birth rate, clinical pregnancy rate, and miscarriage rate.

RESULT(S)

Among the studies analyzing serum progesterone level thresholds <10 ng/mL, a higher serum progesterone level was associated with increased rates of ongoing pregnancy or live birth (relative risk [RR] 1.47, 95% confidence interval [CI] 1.28 to 1.70), higher chance of clinical pregnancy (RR 1.31, 95% CI 1.16 to 1.49), and lower risk of miscarriage (RR 0.62, 95% CI 0.50 to 0.77) in cycles using exclusively vaginal progesterone and blastocyst embryos. There was uncertainty about whether progesterone thresholds ≥10 ng/mL were associated with FET outcomes in sensitivity analyses including all studies, owing to high interstudy heterogeneity and wide CIs.

CONCLUSION(S)

Our findings indicate that there may be a minimum clinically important luteal serum concentration of progesterone required to ensure an optimal endocrine milieu during embryo implantation and early pregnancy after FET treatment. Future clinical trials are required to assess whether administering higher-dose luteal phase support improves outcomes in women with a low serum progesterone level at the time of FET.

PROSPERO NUMBER

CRD42019157071.

Letrozole-induced frozen embryo transfer cycles are associated with a lower risk of hypertensive disorders of pregnancy among women with polycystic ovary syndrome

BACKGROUND

Observational retrospective data suggest that an artificial cycle frozen embryo transfer may be associated with a higher risk of hypertensive disorder of pregnancy than a natural cycle frozen embryo transfer among women with regular ovulatory cycles. The corpus luteum, which is not present in the artificial frozen cycles, is at least partly responsible for this poor obstetrical outcome. However, an artificial cycle is the most frequently used regimen for women with polycystic ovary syndrome undergoing frozen embryo transfer. Whether the risk of hypertensive disorder of pregnancy could be mitigated by employing physiological frozen embryo transfer protocols that lead to the development of a corpus luteum in patients with polycystic ovary syndrome remains unknown.

OBJECTIVE

This study aimed to investigate the impact of letrozole use during frozen embryo transfer cycles on obstetrical and perinatal outcomes of singleton and twin pregnancies compared with artificial frozen cycles among women with polycystic ovary syndrome.

STUDY DESIGN

This retrospective cohort study involved women with polycystic ovary syndrome who had undergone artificial frozen cycles or letrozole-stimulated frozen cycles during the period from 2010 to 2018 at a tertiary care center. The primary outcome was the incidence of hypertensive disorder of pregnancy. A multivariable logistic regression analysis was performed to control for the relevant confounders.

RESULTS

A total of 2427 women with polycystic ovary syndrome were included in the final analysis. Of these women, 1168 underwent artificial cycles and 1259 underwent letrozole treatment, of which 25% of women treated with letrozole alone and 75% of women receiving letrozole combined with gonadotropins. After controlling for maternal characteristics and treatment variables, no significant difference was noticed regarding gestational diabetes mellitus, abnormal placentation, and preterm premature rupture of membranes between groups in both singleton and twin pregnancies. For birth outcomes, the prevalence rates of preterm birth, perinatal death, and birthweight outcomes were all comparable between groups in both singletons and twins. However, singleton pregnancies resulting from letrozole-stimulated cycles had a lower risk of hypertensive disorder of pregnancy than those conceived by artificial cycles (adjusted odds ratio, 0.63; 95% confidence interval, 0.40-0.98). Furthermore, a decreased risk of hypertensive disorder of pregnancy was seen among women with twin deliveries resulting from letrozole-stimulated cycles vs artificial cycles (adjusted odds ratio, 0.52; 95% confidence interval, 0.30-0.87). In addition, the cesarean delivery rate was significantly lower for singletons but not for twins in the letrozole group compared with pregnancies from the artificial cycle group (adjusted odds ratio, 0.63; 95% confidence interval, 0.50-0.78, and adjusted odds ratio, 1.20; 95% confidence interval, 0.65-2.23, respectively).

CONCLUSION

In women with polycystic ovary syndrome undergoing frozen embryo transfer, letrozole use for endometrial preparation was associated with a lower risk of hypertensive disorder of pregnancy than artificial cycles for endometrial preparation. Our findings provided a foundation that the increased risk of hypertensive disorder of pregnancy associated with frozen embryo transfer might be mitigated by utilizing physiological endometrial preparation protocols that lead to the development of a corpus luteum, such as a mild ovarian stimulation cycle for oligo- or anovulatory women.

Secretory products of the corpus luteum and preeclampsia

BACKGROUND

Despite significant advances in our understanding of the pathophysiology of preeclampsia (PE), there are still many unknowns and controversies in the field. Women undergoing frozen-thawed embryo transfer (FET) to a hormonally prepared endometrium have been found to have an unexpected increased risk of PE compared to women who receive embryos in a natural FET cycle. The differences in risk have been hypothesized to be related to the absence or presence of a functioning corpus luteum (CL).

OBJECTIVE AND RATIONALE

To evaluate the literature on secretory products of the CL that could be essential for a healthy pregnancy and could reduce the risk of PE in the setting of FET.

SEARCH METHODS

For this review, pertinent studies were searched in PubMed/Medline (updated June 2020) using common keywords applied in the field of assisted reproductive technologies, CL physiology and preeclampsia. We also screened the complete list of references in recent publications in English (both animal and human studies) on the topics investigated. Given the design of this work as a narrative review, no formal criteria for study selection or appraisal were utilized.

OUTCOMES

The CL is a major source of multiple factors regulating reproduction. Progesterone, estradiol, relaxin and vasoactive and angiogenic substances produced by the CL have important roles in regulating its functional lifespan and are also secreted into the circulation to act remotely during early stages of pregnancy. Beyond the known actions of progesterone and estradiol on the uterus in early pregnancy, their metabolites have angiogenic properties that may optimize implantation and placentation. Serum levels of relaxin are almost undetectable in pregnant women without a CL, which precludes some maternal cardiovascular and renal adaptations to early pregnancy. We suggest that an imbalance in steroid hormones and their metabolites and polypeptides influencing early physiologic processes such as decidualization, implantation, angiogenesis and maternal haemodynamics could contribute to the increased PE risk among women undergoing programmed FET cycles.

WIDER IMPLICATIONS

A better understanding of the critical roles of the secretory products of the CL during early pregnancy holds the promise of improving the efficacy and safety of ART based on programmed FET cycles.

Natural cycle versus hormone replacement cycle for transferring vitrified-warmed embryos in eumenorrhoeic women. A retrospective cohort study

OBJECTIVE

To compare pregnancy, miscarriage and live birth rates and cycle monitoring parameters between Natural Cycle (NC-FET) and Hormone replacement cycle (HRC-FET) in eumenorrhoeic women undergoing vitrified-warmed autologous embryo transfer.

STUDY DESIGN

Single-centre retrospective cohort study analyzed 173 NC-FET and 507 HRC-FET cycles with transfer of day2/3/5/6 embryos. Natural cycle monitoring occurred with serial ultrasound with the first day of the scan determined by the shortest cycle frequency. Serum progesterone was ordered when ultrasound was ambiguous in ascertaining ovulation. For HRC-FET oral estradiol valerate was used in fixed or escalating doses with maximum daily dose of 12 mg. Transdermal estradiol gel was added when desired endometrial thickness was not achieved. Vaginal progesterone was introduced with Endometrial thickness(ET)> = 7 mm. Embryos were transferred after stage-appropriate progesterone exposure. Luteal support was given with vaginal progesterone in NC-FET and vaginal and oral progesterone in HRC-FET. Primary outcome was live-birth-rate. Secondary outcomes were ET, length-of-estrogenic-phase, numbers-of-ultrasounds&hormone-monitoring, pregnancy&miscarriage rate. The odds ratio for live-birth was adjusted for age, embryo number, previous-live-births, previous-losses, past-negative-ET-cycles, IVF-indication and embryo-developmental-stage. Quantitative variables were compared using unpaired-t-test and qualitative variables with chi-square test. Two tailed p-value < 0.05 was considered significant. Binary logistic regression was used to calculate adjusted odds for live-births.

RESULTS

The two cohorts were comparable in age, infertility-duration, previous-live-births, previous-losses, past-negative-ET-cycles, IVF-indication and embryo-developmental-stage. Length-of-estrogenic-phase was significantly shorter for NC-FET than HRC-FET 14.32 ± 2.83vs.18.18 ± 4.48; p = 0.0001) as was mean ultrasound-monitoring-scans (2.73 ± 0.95vs. 3.3 ± 1.04; p = 0.0001). Mean-endometrial-thickness (8.75 ± 1.83vs. 8.5 ± 1.25; p = 0.25) and mean-hormonal-tests (1.75 ± 1.28 vs. 1.88 ± 0.69; p = 0.09) did not differ significantly between NC-FET vs HRC-FET. Significantly higher live births took place in NC-FET vs. HRC-FET (87/173 = 50.3%vs.204/507 = 40.2%;p = 0.026). No significant difference was found in pregnancy rate (66.5% vs. 58%; p = 0.058) or in the pregnancy loss rate (24.3%vs30.6%; p = 0.23). The odds ratio for live-births adjusted for relevant variables was 1.48 (1.03-2.13) in NC-FET compared to HRC-FET.

CONCLUSIONS

NC-FET is a superior method of endometrial preparation compared to HRC-FET in eumenorrhoeic women since it has a shorter estrogenic phase, reduces patient visits to the hospital and improves live birth rates. Future adequately powered studies should look at antenatal and perinatal outcomes, patient satisfaction rates and cost-effectiveness in the two endometrial preparation regimes.

An Integrated Analysis of Network Pharmacology, Molecular Docking, and Experiment Validation to Explore the New Candidate Active Component and Mechanism of Cuscutae Semen-Mori Fructus Coupled-Herbs in Treating Oligoasthenozoospermia

PURPOSE

One of the most common types of male infertility is recognized as oligoasthenozoospermia (OA), characterized by low sperm count and quality in males. As a traditional Chinese medicine (TCM), Cuscutae Semen-Mori Fructus coupled-herbs (CSMFCH) has been known to act a curative effect on OA for thousands of years. Nevertheless, the substantial basis and molecular mechanism of CSMFCH in treating OA remain elusive.

METHODS

Herein, an integrated approach, including network pharmacology, molecular docking, and experiment validation, was utilized to reveal the new candidate active component and mechanism of CSMFCH in treating OA.

RESULTS

The results show that kaempferol is the most significant bioactive component of CSMFCH on OA. The mechanism and targets of CSMFCH against OA are relevant to hormone regulation, oxidant stress, and reproductive promotion. In order to validate network pharmacology results, molecular docking and experiment validation were conducted. In detail, molecular docking was employed to verify the strong binding interactions between kaempferol and the core targets. UHPLC-Q-Orbitrap-MS was used to identify kaempferol in the CSMFCH extract. In vitro and in vivo experiments further proved CSMFCH and kaempferol could enhance the mouse Leydig (TM3) and mouse Sertoli (TM4) cell viability, improve the male reproductive organ weights, sperm quality, and decrease testis tissue damage in the OA mouse model induced by CP.

CONCLUSION

Our results not only identify the new candidate active component of CSMFCH in treating OA but also provide new insights into the mechanisms of CSMFCH against OA.

Frozen Embryo Transfer and Preeclampsia Risk

Worldwide, the use of Assisted Reproductive Technology (ART) has been steadily rising over recent years. With the continuous improvements in cryopreservation techniques and the growing practice of single embryo transfer, the proportion of frozen embryo transfer (FET) cycles has been increasing, therefore raising concern about the safety of this ART technique to both mothers and infants. This review aims to summarize the current evidence regarding the risk of preeclampsia in singleton pregnancies achieved by autologous FET compared to fresh embryo transfer, and to discuss the influence of different protocols used for endometrium preparation in frozen cycles on the risk of this obstetric complication. Several studies have reported a higher risk of hypertensive disorders, including preeclampsia, in pregnancies following FET compared with fresh embryo transfer. Recently, artificial FET cycles, which preclude the development of a corpus luteum, were shown to be associated with an increased preeclampsia risk in comparison with natural and stimulated cycles. Importantly, no difference was found between FET in a modified natural cycle and spontaneous conception. It has been proposed that the absence of the corpus luteum in artificial cycles may, at least partly, contribute to the observed increased risk of preeclampsia. Indeed, the corpus luteum secretes vasoactive hormones, such as relaxin, which are not replaced in artificial cycles, thereby compromising maternal cardiovascular adaptations to pregnancy, resulting in an increased risk of preeclampsia. If these findings are confirmed by a randomized controlled trial, natural, modified natural or stimulated cycles might be preferred over artificial cycles in eligible patients.

Influence of Placental Abnormalities and Pregnancy-Induced Hypertension in Prematurity Associated with Various Assisted Reproductive Technology Techniques

OBJECTIVE

Assisted reproductive technology (ART)-treated women exhibit increased risk of premature delivery compared to fertile women. We evaluated whether ART treatment modalities increase prematurity and whether placental abnormalities and pregnancy-induced hypertensive (PIH) disorders mediate these risks.

METHOD(S)

This retrospective study of ART-treated and fertile deliveries (2004-2017) used an ART-cycle database linked to Massachusetts birth certificates and hospital discharges. Outcomes of late preterm birth (LPTB: 34-36 weeks gestation) and early preterm birth (EPTB: <34 weeks gestation) were compared with term deliveries (≥37 weeks gestation) in ART-treated (linked to the ART database) and fertile (no indicators of infertility or ART) deliveries. ART treatments with autologous oocyte, donor oocyte, fresh or frozen embryo transfer (FET), intracytoplasmic sperm injection (ICSI) and no-ICSI were separately compared to the fertile group. Adjusted odds ratios (AOR) were calculated with multivariable logistic regression: placental abnormalities or PIH were quantified in the pathway as mediators.

RESULTS

There were 218,320 deliveries: 204,438 fertile and 13,882 ART-treated. All treatment types increased prematurity (AOR 1.31-1.58, LPTB; AOR 1.34-1.48, EPTB). Placental abnormalities mediated in approximately 22% and 38% of the association with LPTB and EPTB, respectively. PIH mediated 25% and 33% of the association with LPTB and EPTB in FET and donor oocyte cycles, more than other treatments (<10% LPTB and <13% EPTB).

CONCLUSIONS

ART-treatment and all ART modalities increased LPTB and EPTB when compared with fertile deliveries. Placental abnormalities modestly mediated associations approximately equally, while PIH was a stronger mediator in FET and donor oocyte cycles. Reasons for differences require exploration.

Role of arterial impairment in preeclampsia: should the paradigm shift?

Preeclampsia is a worldwide pregnancy complication with serious short- and long-term maternal and neonatal consequences. Our understanding of preeclampsia pathophysiology has significantly evolved over the last decades with the recognition that impaired arterial function and structure may occur early in the course of pregnancy, preceding the clinic-humoral syndrome and driving long-term cardiovascular disease risk in the future of these patients. Although an early abnormal placentation may be the inciting event for a large proportion of cases, there is growing evidence that challenges the placental hypothesis in all affected women, since placental histopathology lesions thought to be characteristic are neither sensitive nor specific markers for the disorder. Recent hemodynamic investigations and studies on left ventricular function and structure in women with preeclampsia further challenge this universal paradigm and propose that placental dysfunction could be secondary to a maternal cardiovascular maladaptation to pregnancy in certain patients. Supporting this hypothesis, certain vascular features, which are characteristically enhanced in normal pregnancy allowing a healthy vascular adaptation, are absent in preeclampsia and comparable to the nonpregnant population. However, arterial biomechanics in preeclampsia may only not cope with hemodynamic demands of pregnancy but also impose additional detrimental loads to the maternal heart ("impaired left-ventricle-aorta coupling") and transmit pressure and flow disturbances into the fetoplacental circulation ("impaired large arteries-microcirculation coupling"). In this review, we analyze the major role of the arterial dysfunction in the cardiovascular maladaptation hypothesis of preeclampsia, shed light on its potential etiopathogenic link, and discuss the complementary nature of the placental and cardiovascular theories.

Frozen-thawed embryo transfers: time to adopt a more "natural" approach?

The increasing use of frozen-thawed embryo transfer (FET) cycles has magnified the focus on endometrial preparation protocols in assisted reproduction. Emerging evidence suggests that natural cycle (NC) FETs are associated with improved outcomes, and that providers should consider increasing the utilization of NC FET at the expense of the currently favored artificial cycle (AC) FET as primary method for endometrial preparation.

Lower risk of adverse perinatal outcomes in natural versus artificial frozen-thawed embryo transfer cycles: a systematic review and meta-analysis

This systematic review of literature and meta-analysis of observational studies reports on perinatal outcomes after frozen embryo transfer (FET). The aim was to determine whether natural cycle frozen embryo transfer (NC-FET) in singleton pregnancies conceived after IVF decreased the risk of adverse perinatal outcomes compared with artificial cycle frozen embryo transfer (AC-FET). Thirteen cohort studies, including 93,201 cycles, met the inclusion criteria. NC-FET was associated with a lower risk of hypertensive disorders in pregnancy (HDP) (RR 0.61, 95% CI 0.50 to 0.73), preeclampsia (RR 0.47, 95% CI 0.42 to 0.53), large for gestational age (LGA) (RR 0.93, 95% CI 0.90 to 0.96) and macrosomia (RR 0.82, 95% CI 0.69 to 0.97) compared with AC-FET. No significant difference was found in the risk of gestational hypertension and small for gestational age. Secondary outcomes assessed were the risk of preterm birth (RR 0.83, 95% CI 0.79 to 0.88); post-term birth (RR 0.48, 95% CI 0.29 to 0.80); low birth weight (RR 0.84, 95% CI 0.80 to 0.89); caesarean section (RR 0.84, 95% CI 0.77 to 0.91); postpartum haemorrhage (RR 0.39, 95% CI 0.35 to 0.45); placental abruption (RR 0.61, 95% CI 0.38 to 0.98); and placenta accreta (RR 0.18, 95% CI 0.10 to 0.33). All were significantly lower with NC-FET compared with AC-FET. In assessing safety, NC-FET significantly decreased the risk of HDP, preeclampsia, LGA, macrosomia, preterm birth, post-term birth, low birth weight, caesarean section, postpartum haemorrhage, placental abruption and placenta accreta. Further randomized controlled trials addressing the effect of NC-FET and AC-FET on maternal and perinatal outcomes are warranted. Clinicians should carefully monitor pregnancies achieved by FET in artificial cycles prenatally, during labour and postnatally.

Time from oocyte retrieval to frozen embryo transfer in the natural cycle does not impact reproductive or neonatal outcomes

OBJECTIVE

To determine if the time from oocyte retrieval to frozen embryo transfer (FET) in the natural cycle affects reproductive or neonatal outcomes.

DESIGN

Retrospective cohort.

SETTING

Not applicable.

PATIENT(S)

Five hundred and seventy-six consecutive freeze-all cycles from January 2011 to December 2018 followed by natural cycle FET of a single blastocyst.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Primary outcome of live birth; secondary outcomes of preterm delivery (24-37 weeks) and small for gestational age (SGA) with a multivariable logistic regression performed with adjustment for age, infertility diagnosis, ovulatory trigger type, and preimplantation genetic testing (PGT).

RESULT(S)

Before adjustment for confounding, we found a statistically significantly different live-birth rate (57.7% vs. 48.6%) for natural cycle FET occurring in the first versus second menstrual cycle, respectively. In a multivariate analysis, performing a natural cycle FET of a single blastocyst in the second compared with the first menstrual cycle did not statistically significantly impact the odds of live-birth rate. After adjustment for age, diagnosis, and ovulatory trigger type, only PGT was associated with statistically significantly increased odds of live birth compared with no PGT. There were no differences in the incidence of SGA (male, 6.6% vs. 2.3%; female, 9.8% vs. 11.1%) or preterm delivery (1.6% vs. 5.6%) between both groups.

CONCLUSION(S)

Performing a natural cycle FET of a single blastocyst in the second compared with the first menstrual cycle after ovarian stimulation did not statistically significantly impact the odds of live birth or neonatal outcomes.

Fresh versus frozen embryo transfers in assisted reproduction

BACKGROUND

In vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) treatments conventionally consist of a fresh embryo transfer, possibly followed by one or more cryopreserved embryo transfers in subsequent cycles. An alternative option is to freeze all suitable embryos and transfer cryopreserved embryos in subsequent cycles only, which is known as the 'freeze all' strategy. This is the first update of the Cochrane Review on this comparison.

OBJECTIVES

To evaluate the effectiveness and safety of the freeze all strategy compared to the conventional IVF/ICSI strategy in women undergoing assisted reproductive technology.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group Trials Register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, and two registers of ongoing trials from inception until 23 September 2020 for relevant studies, checked references of publications found, and contacted study authors to obtain additional data.

SELECTION CRITERIA

Two review authors (TZ and MZ) independently selected studies for inclusion, assessed risk of bias, and extracted study data. We included randomised controlled trials comparing a 'freeze all' strategy with a conventional IVF/ICSI strategy including a fresh embryo transfer in women undergoing IVF or ICSI treatment.

DATA COLLECTION AND ANALYSIS

The primary outcomes were cumulative live birth rate and ovarian hyperstimulation syndrome (OHSS). Secondary outcomes included effectiveness outcomes (including ongoing pregnancy rate and clinical pregnancy rate), time to pregnancy and obstetric, perinatal and neonatal outcomes.

MAIN RESULTS

We included 15 studies in the systematic review and eight studies with a total of 4712 women in the meta-analysis. The overall evidence was of moderate to low quality. We graded all the outcomes and downgraded due to serious risk of bias, serious imprecision and serious unexplained heterogeneity. Risk of bias was associated with unclear blinding of investigators for preliminary outcomes of the study during the interim analysis, unit of analysis error, and absence of adequate study termination rules. There was an absence of high-quality evidence according to GRADE assessments for our primary outcomes, which is reflected in the cautious language below. There is probably little or no difference in cumulative live birth rate between the 'freeze all' strategy and the conventional IVF/ICSI strategy (odds ratio (OR) 1.08, 95% CI 0.95 to 1.22; I² = 0%; 8 RCTs, 4712 women; moderate-quality evidence). This suggests that for a cumulative live birth rate of 58% following the conventional strategy, the cumulative live birth rate following the 'freeze all' strategy would be between 57% and 63%. Women might develop less OHSS after the 'freeze all' strategy compared to the conventional IVF/ICSI strategy (OR 0.26, 95% CI 0.17 to 0.39; I² = 0%; 6 RCTs, 4478 women; low-quality evidence). These data suggest that for an OHSS rate of 3% following the conventional strategy, the rate following the 'freeze all' strategy would be 1%. There is probably little or no difference between the two strategies in the cumulative ongoing pregnancy rate (OR 0.95, 95% CI 0.75 to 1.19; I² = 31%; 4 RCTs, 1245 women; moderate-quality evidence).  We could not analyse time to pregnancy; by design, time to pregnancy is shorter in the conventional strategy than in the 'freeze all' strategy when the cumulative live birth rate is comparable, as embryo transfer is delayed in a 'freeze all' strategy. We are uncertain whether the two strategies differ in cumulative miscarriage rate because the evidence is very low quality (Peto OR 1.06, 95% CI 0.72 to 1.55; I² = 55%; 2 RCTs, 986 women; very low-quality evidence) and cumulative multiple-pregnancy rate (Peto OR 0.88, 95% CI 0.61 to 1.25; I² = 63%; 2 RCTs, 986 women; very low-quality evidence). The risk of hypertensive disorders of pregnancy (Peto OR 2.15, 95% CI 1.42 to 3.25; I² = 29%; 3 RCTs, 3940 women; low-quality evidence), having a large-for-gestational-age baby (Peto OR 1.96, 95% CI 1.51 to 2.55; I² = 0%; 3 RCTs, 3940 women; low-quality evidence) and a higher birth weight of the children born (mean difference (MD) 127 g, 95% CI 77.1 to 177.8; I² = 0%; 5 RCTs, 1607 singletons; moderate-quality evidence) may be increased following the 'freeze all' strategy. We are uncertain whether the two strategies differ in the risk of having a small-for-gestational-age baby because the evidence is low quality (Peto OR 0.82, 95% CI 0.65 to 1.05; I² = 64%; 3 RCTs, 3940 women; low-quality evidence).

AUTHORS' CONCLUSIONS

We found moderate-quality evidence showing that one strategy is probably not superior to the other in terms of cumulative live birth rate and ongoing pregnancy rate. The risk of OHSS may be decreased in the 'freeze all' strategy. Based on the results of the included studies, we could not analyse time to pregnancy. It is likely to be shorter using a conventional IVF/ICSI strategy with fresh embryo transfer in the case of similar cumulative live birth rate, as embryo transfer is delayed in a 'freeze all' strategy. The risk of maternal hypertensive disorders of pregnancy, of having a large-for-gestational-age baby and a higher birth weight of the children born may be increased following the 'freeze all' strategy. We are uncertain if 'freeze all' strategy reduces the risk of miscarriage, multiple pregnancy rate or having a small-for-gestational-age baby compared to conventional IVF/ICSI.

Increased obstetric and neonatal risks in artificial cycles for frozen embryo transfers?

RESEARCH QUESTION

What are the obstetric and neonatal risks for women conceiving via frozen-thawed embryo transfer (FET) during a modified natural cycle compared with an artificial cycle method.

DESIGN

A follow-up study to the ANTARCTICA randomized controlled trial (RCT) (NTR 1586) conducted in the Netherlands, which showed that modified natural cycle FET (NC-FET) was non-inferior to artificial cycle FET (AC-FET) in terms of live birth rates. The current study collected data on obstetric and neonatal outcomes of 98 women who had a singleton live birth. The main outcome was birthweight; additional outcomes included hypertensive disorder of pregnancy, premature birth, gestational diabetes, obstetric haemorrhage and neonatal outcomes including Apgar scores and admission to the neonatal ward or the neonatal intensive care unit and congenital anomalies.

RESULTS

Data from 82 out of 98 women were analysed according to the per protocol principle. There was no significant difference in the birthweights of children born between groups (mean difference -124 g [-363 g to 114 g]; P = 0.30). Women who conceived by modified NC-FET have a decreased risk of hypertensive disorders of pregnancy compared with AC-FET (relative risk 0.27; 95% CI 0.08-0.94; P = 0.031). Other outcomes, such as rates of premature birth, gestational diabetes or obstetric haemorrhage and neonatal outcomes, were not significantly different.

CONCLUSIONS

The interpretation is that modified NC-FET is the preferred treatment in women with ovulatory cycles undergoing FET when the increased risk of obstetrical complications and potential neonatal complications in AC-FET are considered.

Network pharmacology integrated molecular docking reveals the bioactive components and potential targets of Morinda officinalis-Lycium barbarum coupled-herbs against oligoasthenozoospermia

Oligoasthenozoospermia (OA) is one of the most common types of male infertility affecting sperm count and sperm motility. Unfortunately, it is difficult for existing drugs to fundamentally improve the sperm quality of OA patients, because the pathological mechanism of OA has not been fully elucidated yet. Morinda officinalis-Lycium barbarum coupled-herbs (MOLBCH), as traditional Chinese Medicines, has been widely used for treating OA over thousands of years, but its molecular mechanism is still unclear. For this purpose, we adopted a comprehensive approach integrated network pharmacology and molecular docking to reveal the bioactive components and potential targets of MOLBCH against OA. The results showed that MOLBCH alleviated apoptosis, promoted male reproductive function, and reduced oxidant stress in the treatment of OA. Ohioensin-A, quercetin, beta-sitosterol and sitosterol were the key bioactive components. Androgen receptor (AR), Estrogen receptor (ESR1), Mitogen-activated protein kinase 3 (MAPK3), RAC-alpha serine/threonine-protein kinase (AKT1), Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were the core potential targets. PI3K/Akt signaling pathway, prostate cancer, AGE-RAGE signaling pathway in diabetic complications were the most representative pathways. Moreover, molecular docking was performed to validate the strong binding interactions between the obtained core components and targets. These observations provide deeper insight into the pathogenesis of OA and can be used to design new drugs and develop new therapeutic instructions to treat OA.

Endometrium preparation and perinatal outcomes in women undergoing single-blastocyst transfer in frozen cycles

OBJECTIVE

To investigate the association of endometrium preparation with perinatal outcomes.

DESIGN

Retrospective cohort study.

SETTING

University-affiliated fertility center.

PATIENT(S)

Twenty-one thousand six hundred and forty-eight women who underwent frozen single-blastocyst transfer from January 2013 to March 2019.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Cesarean delivery, preterm delivery (PTD), vaginal PTD, very preterm delivery (VPTD), postterm delivery, low birth weight (LBW), macrosomia, small for gestational age (SGA), large for gestational age (LGA), hypertensive disorders of pregnancy (HDP), gestational diabetes mellitus (GDM), premature rupture of membrane (PROM), placenta previa, and congenital abnormality.

RESULT(S)

Compared with natural cycles, hormone replacement cycles were associated with an increased risk of PTD, VPTD, cesarean delivery, macrosomia, PROM, and HDP. There was a trend toward an increased risk of vaginal PTD and LGA in hormone replacement cycles. Stimulated cycles were associated with an increased risk of postterm delivery and GDM. There was no statistically significant difference in the rate of SGA, placenta previa, or congenital abnormality among the three endometrium preparation methods.

CONCLUSION(S)

Hormone replacement cycles are associated with an increased risk of PTD, VPTD, cesarean delivery, LBW, macrosomia, PROM, and HDP. Stimulated cycles are associated with an increased risk of postterm delivery and GDM.

Adverse obstetric and perinatal outcomes in 1,136 singleton pregnancies conceived after programmed frozen embryo transfer (FET) compared with natural cycle FET

OBJECTIVE

To investigate whether obstetric and perinatal outcomes in pregnancies differ after different frozen embryo transfer (FET) protocols.

DESIGN

Register-based cohort study.

SETTING

Not applicable.

PATIENT(S)

All singleton deliveries after assisted reproductive technology in Denmark from 2006 to 2014. Data consisted of 1,136 deliveries after frozen in vitro fertilization. Frozen embryo transfer cycles were grouped by type of FET protocol: programmed FET (n = 357); modified natural cycle FET (n = 611); and true natural cycle FET (n = 168).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Obstetric outcomes (hypertensive disorders in pregnancy, preterm prelabor rupture of membranes, placenta previa, placental abruption, induction of labor, postpartum hemorrhage, and cesarean section) and perinatal outcomes (post-term birth, preterm birth, birth weight, small for gestational age, large for gestational age).

RESULT(S)

The risk of hypertensive disorders in pregnancy, postpartum hemorrhage, and cesarean section was significantly higher after programmed FET compared with natural cycle FET (modified natural cycle FET and true natural cycle FET). A higher risk of birth weight > 4,500 g was observed in the programmed FET group compared with natural cycle FET.

CONCLUSION(S)

This study shows that obstetric and perinatal outcomes are adversely affected in programmed FET cycles. Hence, when possible, an endometrial preparation with the creation of a corpus luteum should be considered. Properly sized randomized controlled trials of FET in programmed cycle versus natural cycle including perinatal outcomes are warranted in the future.

CLINICAL TRIAL REGISTRATION NUMBER

ISRCTN11780826.

Should the modified natural cycle protocol for frozen embryo transfer be modified? A prospective case series proof of concept study

OBJECTIVE

Modified natural cycles for frozen embryo transfer utilize an ovulation trigger which assists in embryo transfer scheduling and simplifies cycle monitoring. There have been conflicting results with this protocol and modifications may be sought. We wanted to ascertain whether a modified natural protocol for frozen embryo transfer without triggered ovulation but with luteal progesterone support disconnecting the timing of embryo transfer from the timing of the LH surge can achieve a high pregnancy rate.

STUDY DESIGN

Candidates for frozen embryo transfer of 48-h cleavage cell embryos were recruited from May 2016 to April 2018. The patients were monitored for endometrial growth, follicle formation and estradiol, progesterone, and LH hormone levels. After meeting the predetermined criteria, embryo transfer was scheduled. The patients began progesterone treatment 48 h before embryo transfer, regardless of identification of the LH surge if ovulation had not commenced. The predetermined primary outcome was the biochemical pregnancy rate while the secondary outcome included the clinical pregnancy rate and the ongoing pregnancy rate. Patients were monitored to the eighth week of pregnancy, but data was collected from the medical records to provide the live birth rate as well.

RESULTS

Fifty-six women were screened. Eleven women declined or did not meet the inclusion criteria. Three had anovulatory cycles and were excluded. Forty-two women were included in the statistical analysis. The implantation rate was 42.9 % [95 %CI 29.3 %-56.4 %). Of the 42 participants, 25 (59.5 %) conceived [95 % CI 44.0 %-75 %]. Two pregnancies ended in first trimester miscarriage leaving 23 (54.7 %) ongoing pregnancies [95 % CI 39.1 %-70.5 %]. One patient experienced a late abortion such that the live birth rate was 22 of 42 patients or 52.4 % [95 % CI 36.4 %-68.0 %].

CONCLUSION

The proposed modified natural protocol which utilizes progesterone luteal support but does not trigger ovulation, maintains a high pregnancy rate while providing flexibility regarding the day of transfer disconnected from the day of the LH surge. This was a prospective, proof of concept study. This protocol may be suitable for smaller or public in-vitro fertility units whose resources are limited and facilities are not available daily. The high pregnancy and live birth rate that we found provides confidence that this protocol can be part of the armament of protocols the clinician may offer to his patients. Larger studies should confirm these findings.

Frozen-thawed embryo transfer is an independent risk factor for third stage of labor complications

PURPOSE

Third stage of labor complications are more prevalent following singleton vaginal deliveries of gestations conceived through in vitro fertilization (IVF) and fresh embryo transfer. This study aimed to evaluate these complications in pregnancies conceived through frozen-thawed embryo transfer (FET), in which endometrial preparation differs from fresh cycles.

METHODS

A cohort study of all singleton pregnancies conceived through IVF-FET who delivered vaginally at a tertiary medical center during 2007-2017. The study group consisted of 88 IVF-FET gestations (cases) that were matched to 176 spontaneous pregnancies based on age, gravidity, parity and gestational week at delivery (controls). The association between mode of conception and third stage of labor complication rate was examined.

RESULTS

Baseline characteristics were similar between groups, except for a lower prevalence of induction of labor in the control group (23.3% vs. 36.3%, p = 0.03). The rate of post-partum hemorrhage (PPH), manual lysis and revision of the uterine cavity were all higher in pregnancies conceived through IVF-FET versus spontaneously (13.6% vs. 5.7%, p = 0.018; 17% vs. 2.3%, p < 0.001; and 21.6% vs. 6.8%, p < 0.001, respectively). Multivariate analysis adjusting for age, previous cesarean section, induction of labor, neonatal weight and use of analgesia demonstrated that deliveries following IVF-FET were independently associated with an increased risk for third stage of labor complications (estimated OR = 3.45, p = 0.0002).

CONCLUSION

IVF-FET is an independent risk factor for PPH, need for manual lysis and revision of the uterine cavity. Precautionary measures should be undertaken in the third stage in deliveries following IVF-FET, even if no other risk factors are present.

Live Birth Rate of Frozen-Thawed Single Blastocyst Transfer After 6 or 7 Days of Progesterone Administration in Hormone Replacement Therapy Cycles: A Propensity Score-Matched Cohort Study

BACKGROUND

Progesterone administration before transfer in hormone replacement treatment (HRT) is crucial to pregnancy outcomes in frozen-thawed blastocyst transfer (FET), but the optimal progesterone duration is inconsistent. The objective of this study was to investigate live birth rate (LBR) of different progesterone duration before blastocyst transfer in HRT-FET cycles.

METHOD

In this retrospective cohort study, patients underwent first HRT-FET (including suppression HRT) from January 2016 to December 2019 were included. Logit-transformed propensity score matching (PSM) was performed to assess covariates. The primary outcome was live birth rate after 28 weeks' gestation. Basing on different duration of progesterone before transfer, patients were classified into P6-protocol (blastocyst transfer performed on the sixth day), or P7-protocol (blastocyst transfer performed on the seventh day). Subgroup analyses were conducted as follows: age stratification (-35, 35-38, 38-), development days of blastocyst (D5 or D6), blastocyst quality (high-quality or poor-quality), and endometrial preparation protocols (HRT or suppression HRT).

RESULT

After case matching with propensity score methods, a total of 1,400 patients were included finally: 700 with P6-protocol and 700 with P7-protocol. Significantly higher live birth rate (38.43% versus 31.57%, respectively, P = 0.01) and clinical pregnant rate (50.43% versus 44.14%, respectively, P = 0.02) were observed in P6-protocol than those of P7-protocol. First-trimester abortion rates (18.13% versus 20.71%, P = 0.40) and ectopic pregnancy rates (2.27% versus 1.94%, P = 0.77) were similar between P6- and P7-groups. Preterm birth rate, low birth weight rate, newborn sex proportion, neonatal malformation rate were comparable between groups. Significantly higher LBRs were observed in patients with: age under 35, D5 blastocyst transfer, high-quality blastocyst transfer, and undergoing HRT cycles combined P6-protocol.

CONCLUSION

Frozen-thawed blastocyst transfer on the sixth day of progesterone administration in first HRT cycle is related to higher live birth rate compared with transfer on the seventh day, especially among patients aged under 35, D5 blastocyst and/or high-quality blastocyst transfer.

Maternal and Neonatal Complications in Patients With Diminished Ovarian Reserve in In-Vitro Fertilization/Intracytoplasmic Sperm Injection Cycles

BACKGROUND

Diminished ovarian reserve (DOR) is one of the most intractable clinical issues in human reproduction and is reported to be associated with raised risk of recurrent pregnancy loss and aneuploid blastocysts. In this study, we aimed to explore whether DOR was also associated with maternal and neonatal complications in in-vitro fertilization/intracytoplasmic sperm injection cycles.

METHODS

A retrospective cohort study including women below 40 years of age who achieved singleton live birth after fresh embryo transfer in in-vitro fertilization/intracytoplasmic sperm injection cycles in a single center from January 2012 to June 2019 was conducted. Participants with DOR, defined as basal follicle-stimulating hormone (FSH) ≥ 10IU/L and antimullerian hormone (AMH) < 1.2ng/ml, were enrolled as the study group. The controls were 1:2 matched by age and body mass index with FSH < 10IU/L and AMH ≥ 1.2ng/ml. Maternal and neonatal complications were compared between the DOR group and the controls.

RESULTS

A total of 579 women, 193 in the DOR group and 386 matched as controls, were included in this study. Compared to controls, the incidence of hypertensive disorders of pregnancy was significantly increased in the DOR group (5.7% vs. 2.1%, P = 0.021). DOR patients also presented slightly higher incidences of preterm birth (10.9% vs. 7.5%, P = 0.174) and low birthweight (6.2% vs. 5.4%, P = 0.704) yet without statistical significances. The incidences of gestational diabetes mellitus and placenta previa were comparable between the two groups.

CONCLUSION

Compared to women with normal ovarian reserve, women with diminished ovarian reserve might have elevated incidence of hypertensive disorders of pregnancy. Patients with diminished ovarian reserve might need more strict antenatal care.

Endometrial function in women with polycystic ovary syndrome: a comprehensive review

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility. An endometrial component has been suggested to contribute to subfertility and poor reproductive outcomes in affected women.

OBJECTIVE AND RATIONALE

The aim of this review was to determine whether there is sufficient evidence to support that endometrial function is altered in women with PCOS, whether clinical features of PCOS affect the endometrium, and whether there are evidence-based interventions to improve endometrial dysfunction in PCOS women.

SEARCH METHODS

An extensive literature search was performed from 1970 up to July 2020 using PubMed and Web of Science without language restriction. The search included all titles and abstracts assessing a relationship between PCOS and endometrial function, the role played by clinical and biochemical/hormonal factors related to PCOS and endometrial function, and the potential interventions aimed to improve endometrial function in women with PCOS. All published papers were included if considered relevant. Studies having a specific topic/hypothesis regarding endometrial cancer/hyperplasia in women with PCOS were excluded from the analysis.

OUTCOMES

Experimental and clinical data suggest that the endometrium differs in women with PCOS when compared to healthy controls. Clinical characteristics related to the syndrome, alone and/or in combination, may contribute to dysregulation of endometrial expression of sex hormone receptors and co-receptors, increase endometrial insulin-resistance with impaired glucose transport and utilization, and result in chronic low-grade inflammation, immune dysfunction, altered uterine vascularity, abnormal endometrial gene expression and cellular abnormalities in women with PCOS. Among several interventions to improve endometrial function in women with PCOS, to date, only lifestyle modification, metformin and bariatric surgery have the highest scientific evidence for clinical benefit.

WIDER IMPLICATIONS

Endometrial dysfunction and abnormal trophoblast invasion and placentation in PCOS women can predispose to miscarriage and pregnancy complications. Thus, patients and their health care providers should advise about these risks. Although currently no intervention can be universally recommended to reverse endometrial dysfunction in PCOS women, lifestyle modifications and metformin may improve underlying endometrial dysfunction and pregnancy outcomes in obese and/or insulin resistant patients. Bariatric surgery has shown its efficacy in severely obese PCOS patients, but a careful evaluation of the benefit/risk ratio is warranted. Large scale randomized controlled clinical trials should address these possibilities.

The effect of letrozole versus artificial hormonal endometrial preparation on pregnancy outcome after frozen-thawed embryos transfer cycles: a randomized clinical trial

BACKGROUND

Considering that clinical trial studies are limited in polycystic ovary syndrome (PCOS) patients, and there is no consensus on an optimum endometrial preparation protocol for frozen embryo transfer (FET), the present study was designed as a randomized clinical trial to compare the reproductive outcomes following stimulated cycles with letrozole plus human menopausal gonadotropin (HMG) for endometrial preparation compared with routine AC-FET.

METHODS

This randomized controlled trial was carried out on infertile PCOS patients who underwent IVF/ICSI and FET cycles in Arash Women's Hospital affiliated to Tehran University of Medical Sciences between September 2018 and January 2020. PCOS diagnosis was based on the Rotterdam criteria. Eligible patients were randomly allocated into two groups: stimulated cycle with letrozole plus (HMG) (intervention group) and routine artificial hormonal endometrial preparation (control group).

RESULTS

One hundred seventy-seven infertile patients were recruited for participation in the study. Of these, 57 women were excluded due to non-eligibility for entering the study, and a total of 120 patients were randomly assigned to two study groups. After follow up, the cycle outcomes of 57 patients in the intervention group and 59 patients in the control group were compared. The data analysis showed that the two groups did not have significant differences in fundamental and demographic characteristics. After the intervention, there were no significant differences in implantation rate, chemical, ectopic, and clinical pregnancy rates between groups. Moreover, the rates of miscarriage and ongoing pregnancy were similar between groups (P > 0.05).

CONCLUSIONS

We found similar pregnancy outcomes with two endometrial preparation methods. Noting that each treatment centre should select the most beneficial and cost-effective method with the least adverse effects for patients, letrozole preparations for FET could be incorporated into possible options; however, establishing this approach as first-line treatment is premature in light of current evidence, and future randomized clinical trials with larger sample sizes are required for widespread application.

TRIAL REGISTRATION

The study was also registered in the Iranian Registry of Clinical Trials on March 20th, 2020. ( IRCT20090526001952N12 at www.irct.ir , registered retrospectively).

Optimal time interval between hysteroscopic polypectomy and frozen-thawed blastocyst transfer: A retrospective study

The optimal timing of frozen-thawed blastocyst transfer following hysteroscopic polypectomy is an important and unanswered clinical question. In this study, we conducted a retrospective survey of cases from an infertility center at an academic hospital. We reviewed the charts of all patients who received in-vitro fertilization and frozen-thawed blastocyst transfers (FBT) at the center from January 2009 to November 2019. One hundred and two patients with prior diagnosis of endometrial polyp that were treated with hysteroscopic polypectomy before received their first FBT at the center were identified as cases. Patients without prior diagnosis of endometrial polyp, and who received their first FBT at the center were defined as controls. Controls were enrolled at a 1-to-1 ratio to the cases. The cases and controls did not show differences in baseline characteristics, endometrial thickness, or the number of good blastocysts transferred. The clinical pregnancy rates and live birth rates were similar. Regarding the optimal interval between polypectomy and FBT, a cut-off of 120 days was identified from the ROC curve. A stratified analysis showed that when FBT was performed within an interval of 120 days after polypectomy, there were higher biochemical pregnancy rates (73.2%, 45.2%; OR 3.3; P = .007) and clinical pregnancy rates (64.8%, 41.9%; OR 2.54; P = .032), when compared with intervals greater than 120 days. There were no significant differences in implantation and live birth rates. In conclusion, pregnancy rates following FBT in patients who had received prior endometrial polypectomy were comparable to pregnancy rates after FBT in patients without endometrial polyp. Subgroup analysis showed that an interval greater than 120 days between hysteroscopic polypectomy and FBT was associated with decreased pregnancy rates. Patients who wish to receive embryo transfer after polypectomy should wait no longer than 120 days.