Number of embryos transferred could possibly be associated with angular pregnancy in in vitro fertilization-embryo transfer

OBJECTIVE

The probability of embryo implantation in an abnormal location is significantly higher in assisted reproductive technology (ART) than in natural pregnancies. Angular pregnancy is an eccentric intrauterine pregnancy with embryo implantation in the lateral superior angle of the uterine cavity. Cycle-level factors associated with angular pregnancy in patients conceived with ART needed to be explored.

METHODS

A total of 11 336 clinical pregnancies cycles were included. Angular pregnancy rate was compared among groups according to the type of embryos transferred. Among them, 53 cases of angular pregnancy and 159 cases of normal intrauterine pregnancy were screened out using propensity score matching. Risk factors of angular pregnancy were explored.

RESULTS

The angular pregnancy rate was 0.31% (14/4572) in the day 5 blastocyst transfer group, 0.58% (39/6764) in non-day 5 embryo transfer group, with 0.55% (29/5280) in day 3 embryo transfer and 0.67% (10/1484) in the day 6 blastocyst group, respectively. A multifactor regression analysis was performed and indicated that the number of embryos transferred was significantly associated with angular pregnancy (P = 0.031, OR, 2.23, 95% CI: 1.09-4.68).

CONCLUSION

Multiple embryo transfer could possibly be associated with an increased incidence of angular pregnancy in patients conceived with ART.

The effect of an extended culture period on birth weight among singletons born after single or double vitrified embryo transfer

Aim

To evaluate the effect of an extended culture period on birth weight among singletons born after vitrified-warmed embryo transfer.

Methods

A retrospective cohort study was performed among 12400 women who gave birth to 1015, 1027, 687, and 9671 singletons after single blastocyst transfer, single cleavage-stage embryo transfer, double blastocyst transfer, and double cleavage-stage embryo transfer, respectively.

Results

The unadjusted birth weight of singletons born after vitrified blastocyst transfer were heavier than those born after cleavage-stage transfer (β=30.28, SE=13.17, P=0.022), as were the adjusted birth weights (β=0.09, SE=0.03, P=0.007). In addition, there was a 37% increased odd of having an infant with high birth weight after vitrified blastocyst transfer compared with vitrified cleavage stage transfer (OR=1.37, 95% CI:1.07-1.77).

Conclusion

The unadjusted and adjusted birth weight and odds of having an infant with high birth weight significantly increased after blastocyst transfer compared with cleavage-stage embryo transfer in vitrified-warmed cycles.

Benefits of Blastocyst Transfer With at Least Three Good-Quality Cleavage-stage Embryos in Women of Advanced Maternal Age: A Retrospective Analysis

OBJECTIVES

Limited studies on the benefits of blastocyst transfer in advanced maternal age (AMA) (≥40 years) have been reported. Our objective was to find whether blastocyst-stage embryo transfer improves pregnancy and live birth rates in women ≥40 years who have 3 or more good-quality cleavage-stage embryos.

METHODS

All fresh in vitro fertilization-intracytoplasmic sperm injection cycles performed from January 2020 to December 2021 in AMA women that progressed to transfer were considered for analysis. We compared fresh and cumulative ongoing pregnancy rates in AMA women of those who had a cleavage-stage transfer, while meeting the criteria for extended culture (≥3 high-quality embryos, group 1), and those who underwent blastocyst transfer (group 2). Demographic parameters, stimulation, embryology, fresh and cumulative ongoing pregnancy rates, and clinical miscarriage rates were compared.

RESULTS

During the study period, 255 cycles were analyzed including group 1 (n = 99) and group 2 (n = 156). Group 1 participants were older and had a greater number of embryos for transfer. Fresh and cumulative ongoing pregnancy rates per transfer were higher in group 2 compared to group 1 (23.4% vs. 13.1%, P = 0.04; 25.5% vs. 14.1%, P = 0.03), while overall miscarriage rates were higher in group 1 than group 2 (51.7% vs. 25%, P = 0.01).

CONCLUSIONS

Blastocyst culture provides a benefit to AMA women who have at least 3 good-quality embryos on day 3 resulting in significantly higher fresh and cumulative ongoing pregnancy rates and lower miscarriage compared to cleavage-stage transfers.

Effect of Elevated Progesterone Levels on hCG Trigger Day on Clinical Pregnancy Outcome in Short-Acting GnRHa Downregulated Cycles

Background

Previous studies suggested higher serum progesterone (P) levels were strongly associated with a lower clinical pregnancy rate (CPR) for in vitro fertilization-embryo transfer (IVF-ET). However, the effect of increased serum P levels on the day of human chorionic gonadotropin (hCG) administration on clinical outcomes in short-acting gonadotropin-releasing hormone agonist (GnRHa) downregulated IVF-ET cycles remains unclear.

Methods

We conducted a retrospective cohort study from January 2017 to December 2021, which included a total of 1664 patients receiving their first short-acting GnRHa IVF-ET cycles at our reproductive medicine centre of Nanjing Drum Tower Hospital. The smooth curve fitting and interaction analysis were employed to analyse the association between the CPR and the serum P levels with different embryo types (cleavage-stage embryo or blastocyst). In addition, total cycles were grouped according to different P levels on the trigger day of hCG administration for further analysis.

Results

The CPR of patients with increased serum P level (higher than 1.5 ng/mL) on the hCG day did not decrease. A smoothing curve fitting showed that the CPR did not change obviously with the increase in serum P levels. Subgroup analysis of different types of embryos transferred showed that no correlation was observed between the CPR and serum P levels on the day of hCG administration in cleavage-stage embryo transfer cycles. However, the CPR of patients receiving blastocyst transfer showed a downward trend with the increase in serum P levels. At the same time, an interaction analysis also confirmed that the CPR of blastocyst transfer was more likely to be affected by elevated serum P levels on the hCG day.

Conclusion

In the luteal phase short-acting GnRHa downregulated IVF-ET cycles, the elevated serum P levels on the hCG day did not affect the CPR of cleavage-stage embryo transfer but reduced the CPR of blastocyst transfer.

Factors affecting male-to-female ratio at birth in frozen-thawed embryo transfer cycles: a large retrospective cohort study

Background

ICSI (intracytoplasmic sperm injection) leads to a reduced male-to-female ratio at birth, whereas blastocyst transfer results in an increased male-to-female ratio. However, limited knowledge exists regarding the impact of these factors on the live birth rate for each gender. This study aimed to investigate the influence of patient characteristics and treatment parameters on the live birth rate for each gender, as well as the ultimate male-to-female ratio at birth in frozen-thawed embryo transfer (FET) cycles.

Method

This retrospective cohort study involved a total of 28,376 FET cycles and 9,217 subsequent deliveries, spanning from January 2003 to December 2015. The study consisted of two parts. First, logistic regression models were constructed to determine the factors influencing the male-to-female ratio among babies born after FET. Second, we aimed to investigate the mechanisms underlying this sex ratio imbalance by analyzing data from all transfer cycles. Generalized estimated equations were employed to assess the impact of risk factors on rates of male and female live births separately.

Results

ICSI resulted in a lower proportion of male offspring compared to in vitro fertilization (IVF) (50.1% vs. 53.7%, aOR: 0.87, 95% CI: 0.80-0.96). Conversely, blastocyst transfer yielded a higher proportion of male offspring than cleavage-stage embryo transfer (58.7% vs. 51.6%, aOR: 1.32, 95% CI: 1.17-1.48). Analysis of all cycles indicated that ICSI resulted in a reduced likelihood of male live birth in comparison to IVF (19.8% vs. 21.6%, aOR: 0.90, 95% CI: 0.83-0.97). However, the transfer of blastocysts rather than cleavage-stage embryos not only increased the chance of male live birth (26.9% vs. 20.2%, aOR: 1.70, 95% CI:1.56-1.85) but also facilitated female live birth (20.3% vs. 19.3%, aOR: 1.26, 95% CI: 1.15-1.39).

Conclusion

ICSI was associated with a reduction in the male-to-female sex ratio and a lower rate of male live births, while blastocyst transfer was associated with an increased male-to-female sex ratio at birth and a higher rate of male live births.

Sequential embryo transfer versus double cleavage-stage embryo or double blastocyst transfer in patients with recurrent implantation failure with frozen-thawed embryo transfer cycles: a cohort study

Background

Recurrent implantation failure (RIF) is more common among patients receiving assisted reproductive treatment. Many efforts have been made to increase the incidence of clinical pregnancy among patients with RIF. The effect of the sequential transfer procedure, a two-step interval transfer of a cleavage-stage embryo followed by a blastocyst in one transfer cycle, on the clinical outcomes of RIF patients remains controversial.

Methods

In total, 1774 frozen-thawed embryo transfer (FET) cycles in RIF patients were included. Of these cycles, 302 were sequential embryo transfer (ET) cycles, 979 were double day 3 cleavage-stage ET cycles, and 493 were double blastocyst ET cycles. The primary outcomes were the rates of implantation, clinical pregnancy and multiple pregnancy, and the secondary outcomes were the rates of hCG positive, early miscarriage and ectopic pregnancy.

Results

The implantation, hCG positive, and clinical pregnancy rates in the sequential ET group (32.1%, 58.9%, 50.7%) were significantly higher than those in the day 3 cleavage-stage ET group (24.9%, 46.5%, 40.4%) and were similar to those in the blastocyst transfer group (30.1%, 56.4%, 47.1%). The early miscarriage rate in the blastocyst transfer group was significantly higher than that in the cleavage-stage ET group (17.2% vs. 8.1%, P <0.05), while the ectopic pregnancy rate in the blastocyst transfer group was significantly lower than that in the cleavage-stage ET group (0.4% vs. 3.0%, P <0.05). The multiple pregnancy rate in the sequential ET group was significantly lower than that in the cleavage-stage ET group (17.0% vs. 25.5%, P <0.05) and the blastocyst transfer group (17.0% vs. 27.6%, P <0.05). When cycles of blastocyst culture failure were excluded, the clinical pregnancy rate was significantly higher (55.7% vs. 47.1%, P <0.05), and the early miscarriage rate and multiple pregnancy rate were significantly lower (8.5% vs. 17.2%, 17.7% vs. 27.6%; P <0.05, respectively) in the sequential ET group than in the double blastocyst ET group.

Conclusions

Sequential embryo transfer in FET cycles could improve the clinical outcomes of patients with RIF.

Dynamic peripheral blood microRNA expression landscape during the peri-implantation stage in women with successful pregnancy achieved by single frozen-thawed blastocyst transfer

STUDY QUESTION

What are the dynamic expression features of plasma microRNAs (miRNAs) during the peri-implantation period in women with successful pregnancy via single frozen-thawed blastocyst transfer?

SUMMARY ANSWER

There is a significant change in the plasma miRNA expression profile before and after blastocyst transfer, during the window of implantation.

WHAT IS KNOWN ALREADY

The expression of miRNAs in peripheral blood has indicative functions during the peri-implantation period. Nevertheless, the dynamic expression profile of circulating miRNAs during the peri-implantation stage in women with a successful pregnancy has not been studied.

STUDY DESIGN SIZE DURATION

Seventy-six women treated for infertility with a single frozen-thawed blastocyst transfer in a natural cycle were included in this study. Among them, 57 women had implantation success and a live birth, while 19 patients experienced implantation failure. Peripheral blood samples were collected at five different time points throughout the peri-implantation period, including D0 (ovulation day), D3, D5, D7, and D9 in this cycle of embryo transfer. The plasma miRNAs in women with blastocyst transfer were isolated, sequenced, and analyzed.

PARTICIPANTS/MATERIALS SETTING METHODS

Peripheral blood samples were collected in EDTA tubes and stored at -80°C until further use. miRNAs were isolated from blood, cDNA libraries were constructed, and the resulting sequences were mapped to the human genome. The plasma miRNAs were initially analyzed in a screening cohort (n = 34) with successful pregnancy. Trajectory analysis, including a global test and pairwise comparisons, was performed to detect dynamic differentially expressed (DE) miRNAs. Fuzzy c-means clustering was conducted for all dynamic DE miRNAs. The correlation between DE miRNAs and clinical characteristics of patients was investigated using a linear mixed model. Target genes of the miRNAs were predicted, and functional annotation analysis was performed. The expression of DE miRNAs was also identified in a validation set consisting of women with successful (n = 23) and unsuccessful (n = 19) pregnancies.

MAIN RESULTS AND THE ROLE OF CHANCE

Following small RNA sequencing, a total of 2656 miRNAs were determined as valid read values. After trajectory analysis, 26 DE miRNAs (false discovery rate < 0.05) were identified by the global test, while pairwise comparisons in addition identified 20 DE miRNAs. A total of seven distinct clusters representing different temporal patterns of miRNA expression were discovered. Nineteen DE miRNAs were further identified to be associated with at least one clinical trait. Endometrium thickness and progesterone level showed a correlation with multiple DE miRNAs (including two of the same miRNAs, hsa-miR-1-3p and hsa-miR-6741-3p). Moreover, the 19 DE miRNAs were predicted to have 403 gene targets, and there were 51 (12.7%) predicted genes likely involved in both decidualization and embryo implantation. Functional annotation for predicted targets of those clinically related DE miRNAs suggested the involvement of vascular endothelial growth factor and Wnt signaling pathways, as well as responses to hormones, immune responses, and cell adhesion-related signaling pathways during the peri-implantation stage.

LARGE SCALE DATA

The raw miRNA sequence data reported in this article have been deposited in the Genome Sequence Archive (GSA-Human: HRA005227) and are publicly accessible at https://ngdc.cncb.ac.cn/gsa-human/browse/HRA005227.

LIMITATIONS REASONS FOR CAUTION

Although the RNA sequencing results revealed the global dynamic changes of miRNA expression, further experiments examining the clinical significance of the identified DE miRNAs in embryo implantation outcome and the relevant regulatory mechanisms involved are warranted.

WIDER IMPLICATIONS OF THE FINDINGS

Understanding the dynamic landscape of the miRNA transcriptome could shed light on the physiological mechanisms involved from ovulation to the post-implantation stage, as well as identifying biomarkers that characterize stage-related biological process.

STUDY FUNDING/COMPETING INTERESTS

The study was funded by the Major clinical research project of Tangdu Hospital (2021LCYJ004) and the Discipline Platform Improvement Plan of Tangdu Hospital (2020XKPT003). The funders had no influence on the study design, data collection, and analysis, decision to publish, or preparation of the article. There are no conflicts of interest to declare.

The Relationship between Number of Supernumerary Blastocysts Cryopreserved and Probability of a Live Birth Outcome after Single Fresh Blastocyst Transfer: Analysis of over 10 Thousand Cycles

The ability to predict the likelihood of a live birth after single fresh embryo transfer is an important part of fertility treatment. While past studies have examined the likelihood of live birth based on the number of oocytes retrieved and cleavage-stage embryos available, the odds of a live birth based on the number of supernumerary blastocysts cryopreserved following a fresh embryo transfer has not been rigorously studied. We performed a retrospective analysis, stratified by age, on patients undergoing their first fresh autologous single day 5 blastocyst transfer to assess relationship between the likelihood of a live birth and number of supernumerary blastocysts cryopreserved. In patients aged <35 years and 35-39 years old, the likelihood of a live birth increased linearly between 1 and 6 supplementary blastocysts and non-linearly if 10 or more blastocysts were cryopreserved. When aged 40 years and above, the likelihood of a live birth increased linearly up to 4 cryopreserved blastocysts and then non-linearly if 10 or more blastocysts were cryopreserved. The present study demonstrated a non-linear relationship between the number of supernumerary blastocysts cryopreserved and the likelihood of a live birth after single blastocyst transfer in the first autologous fresh IVF/ICSI cycle across different age groups.

Odds and Predictors of Monozygotic Twinning in a Multicentre Cohort of 25,794 IVF Cycles

The rate of monozygotic twinning (MZT) has seen a gradual increase in recent years. Numerous parameters involved in ART procedures are blamed for this surge, even though the exact explanation is as yet unknown. Our study's objectives were to determine the risk variables for monozygotic twinning after ART and to estimate their prevalence. We examined 25,794 IVF cycles for the incidence of monozygotic twinning in this observational analysis. Our study, which was carried out across seven tertiary IVF centres over the course of four years, found an overall MZT rate of 0.37% per embryo transfer procedure and 0.88% of all pregnancies. Monozygotic twinning was more commonly seen in fresh single-embryo transfer (SET) and blastocyst transfer cycles. Larger multicentre studies are needed to explore the potential risk variables.

Higher miscarriage rate in subfertile women with endometriosis receiving unbiopsied frozen-warmed single blastocyst transfers

Background: Assisted reproductive technology treatment is recommended to overcome endometriosis-associated infertility but current evidence is controversial. Endometriosis is associated with lower antral follicle count (AFC) and oocyte yield but similar clinical outcomes compared to controls. Unaffected ovarian stimulation response and embryological outcomes but lower clinical pregnancy and live birth rates and higher miscarriage rates have been reported, implying direct impact on endometrial receptivity. With evidence emerging on the benefit of frozen-warmed and blastocyst stage transfer, we investigated ART outcomes in endometriosis using homogeneous case-control groups. Methods: This is a retrospective observational case-control study including n = 66 frozen-warmed unbiopsied single blastocyst transfers of patients with endometriosis and n = 96 of women exhibiting idiopathic sterility. All frozen-warmed transfers followed artificial endometrial preparation. Results: In control women, the mean number of oocytes recovered at oocyte pick up was higher compared to women with endometriosis (15.3 ± 7.1 vs. 12.7 ± 5.2, p = 0.025) but oocyte maturation index (mature oocytes/total oocytes at oocyte pick up) was significantly higher for endometriosis (48.2% vs. 34.0%, p = 0.005). The same was shown for the subgroup of 44 endometriosis patients after endometrioma surgery when compared with controls (49.1% vs. 34.0%, p = 0.014). Clinical pregnancy rate was not higher in endometriosis but was close to significance (47.0% vs. 32.3%, p = 0.059) while live birth rate was comparable (27.3% vs. 32.3%, p = 0.746). Miscarriage rate was higher in the endometriosis group (19.7% vs. 7.3%, p = 0.018). A significantly higher AFC was observed in the control group in comparison with the endometriosis group (16.3 ± 7.6 vs. 13.4 ± 7.0, p = 0.014). Live birth rate did not differ when comparing all endometriosis cases (p = 0.746), ASRM Stage I/II and Stage III/IV (p = 0.348 and p = 0.888) with the control group but the overall pregnancy rate was higher in ASRM Stage I/II (p = 0.034) and miscarriage rate was higher in ASRM Stage III/IV (p = 0.030) versus control. Conclusion: Blastocyst transfers in women with endometriosis originate from cycles with lower AFC but higher share of mature oocytes than in control women, suggesting that endometriosis might impair ovarian reserve but not stimulation response. A higher miscarriage rate, independent of blastocyst quality may be attributed to an impact of endometriosis on the endometrium beyond the timing of implantation.

Letrozole-induced endometrial preparation improved the pregnancy outcomes after frozen blastocyst transfer compared to the natural cycle: a retrospective cohort study

Background

Letrozole treatment is considered an effective option in endometrial preparation for frozen embryo transfers in patients with ovulation disorders or irregular menstruation; however, the effectiveness of letrozole-induced endometrial preparation remains unclear in ovulatory patients. Furthermore, there is no comparative study reporting on pregnancy complications and congenital anomalies after frozen embryo transfers comparing natural and letrozole-assisted cycles. This study examined whether letrozole-induced endometrial preparation affected pregnancy outcomes, perinatal outcomes, and congenital anomalies after single vitrified-warmed blastocyst transfers (SVBTs) in ovulatory patients, as compared with the natural cycle.

Methods

This historic cohort study included only patients with unexplained infertility. Overall, 14,611 patients who underwent SVBTs between July 2015 and June 2020, comprising both natural and letrozole-assisted cycles, were included. Multiple covariates that impact outcomes were used for propensity score matching; 1,911 patients in the letrozole group were matched to 12,700 patients in the natural group, and the clinical records of 1,910 patients in each group were retrospectively analysed. Cycle characteristics, pregnancy outcomes (clinical pregnancy, ongoing pregnancy, and live birth), and incidence of pregnancy complications and congenital anomalies were statistically compared between the two groups.

Results

Multivariate logistic regression analysis showed that letrozole administration during SVBT cycles significantly improved the live birth rate (P = 0.0355). Gestational age, birth length, birth weight, and infant sex, as well as the incidence of pregnancy complications and birth defects, were statistically comparable between the two groups. Furthermore, multivariate logistic regression analysis revealed that the perinatal outcomes were not affected by letrozole-induced endometrial preparation.

Conclusions

Letrozole-induced endometrial preparation improved the live birth rate compared with the natural cycle, without adverse effects on perinatal outcomes and congenital anomalies after SVBTs. Therefore, letrozole-induced endometrial preparation might be a safe and more effective strategy, especially for patients with insufficient luteal function.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-05174-0.

Blastocyst Transfer: A Risk Factor for Gestational Diabetes Mellitus in Women Undergoing In Vitro Fertilization

BACKGROUND

The risk of developing gestational diabetes mellitus (GDM) is higher in women undergoing assisted reproductive treatment than in women conceiving spontaneously.

OBJECTIVES

To determine whether the GDM risk after day-3 embryo transfer differs from the GDM risk after day-5 blastocyst transfer.

METHODS

Prospective observational study in women becoming pregnant after first fresh embryo or blastocyst transfer.

RESULTS

A total of 1579 women got pregnant and had live birth; 1300 women got day-3 embryo transfer only, whereas 279 women received at least 1 blastocyst. Of 1579 women, 252 developed GDM. Age, body mass index, baseline estradiol, baseline high-density lipoprotein, and progesterone on the day of human chorionic gonadotropin injection were not different in women receiving day-3 embryos only vs women receiving at least 1 blastocyst. The number and quality of retrieved oocytes were not different in women receiving day-3 embryo transfer from those receiving blastocysts. Our study confirmed already established GDM risk factors such as age and body mass index, baseline estradiol, and high-density lipoprotein, as well as progesterone after ovarian stimulation. We furthermore demonstrate that the GDM incidence in women receiving day-5 blastocyst transfer was significantly higher than those who received day-3 embryo transfer (21.15% vs 14.85%; P = 0.009). Considering confounding factors, we likewise saw that blastocyst transfer was an independent procedure-related GDM risk factor [P = 0.009, Exp (B): 1.56, 95% CI: 1.12-2.18].

CONCLUSION

Blastocyst transfer after in vitro fertilization/intracytoplasmic sperm injection increases the risk of developing GDM.

Obstetric and perinatal risks in 4601 singletons and 884 twins conceived after fresh blastocyst transfers: a Nordic study from the CoNARTaS group

STUDY QUESTION

Are obstetric and perinatal outcomes in pregnancies after fresh blastocyst transfer (BT) comparable with those born after fresh cleavage stage transfer (CT) and spontaneous conception (SC)?

SUMMARY ANSWER

Fresh BT is associated with a higher risk of placental and perinatal complications.

WHAT IS KNOWN ALREADY

BT optimizes the selection of top-quality embryos and increases pregnancy and live birth rates per transfer compared to CT. However, concerns have been raised as extended culture duration may increase obstetric complications and impair perinatal outcomes. Previous studies have shown a higher risk of preterm birth (PTB) among infants born after BT compared with CT. Pregnancies after BT are also prone to a higher risk of same-sex twins after single embryo transfer (SET).

STUDY DESIGN, SIZE, DURATION

A retrospective register-based cohort study used data from Denmark, Norway and Sweden including three cohorts: 56 557 singletons and 16 315 twins born after fresh IVF/ICSI cycles and 2 808 323 SC singletons in Denmark (birth years 1997-2014), Norway (2010-2015) and Sweden (2002-2015). Of the fresh IVF/ICSI singletons, 4601 were born after BT and 51 956 after CT. The twin cohort consisted of 884 fresh IVF/ICSI children born after BT and 15 431 fresh IVF/ICSI children born after CT.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Data were obtained from a large Nordic cohort of children born after ART and SC initiated by the Committee of Nordic ART and Safety (CoNARTaS). The CoNARTaS cohort was established by cross-linking National ART-, Medical Birth-, and National Patients Registers using the unique personal identification number, allocated to every citizen in the Nordic countries. Obstetric and perinatal outcomes after BT, CT and SC were compared using logistic regression analysis. For perinatal outcomes, we calculated gestational age based on the date of oocyte pick-up (OPU) and in sensitivity analyses on data from Denmark and Norway, we also calculated gestational age based on the second-trimester ultrasonography (US) scan. Risk of pregnancies with same-sex twins after SET was used as a proxy for risk of monozygotic twins. Adjustments were made for child's sex, birth year, parity (0 or >1), maternal age, body mass index, smoking, educational level, fertilization method (IVF/ICSI), the number of aspirated oocytes, SET and country. Information on educational level and the number of aspirated oocytes was not available for Norway. Children born after frozen embryo transfer were not included. The birth cohorts were restricted according to the year in which BT was introduced in the different countries.

MAIN RESULTS AND THE ROLE OF CHANCE

A higher risk of placenta previa was found in singleton pregnancies after BT compared with CT (adjusted odds ratio [aOR] 2.11 [95% CI 1.76; 2.52]). Singletons born after BT had a higher risk of PTB (aOR 1.14 [95% CI 1.01; 1.29]) compared with CT singletons, when estimated based on OPU. Furthermore, an altered male/female ratio (aOR 1.13 [95% CI 1.06; 1.21]) with more males following BT compared with CT was seen. Risk of same-sex twins after SET was higher after single BT compared with single CT (aOR 1.94 [95% CI 1.42; 2.60]).

LIMITATIONS, REASONS FOR CAUTION

Residual confounding cannot be excluded, in particular related to duration and cause of infertility that we could not adjust for due to lack of reliable data.

WIDER IMPLICATIONS OF THE FINDINGS

Extended embryo culture to the blastocyst stage has the potential to compromise obstetric and perinatal outcomes in fresh cycles. These results are important since an increasing number of IVF/ICSI treatments are performed as BT.

STUDY FUNDING/COMPETING INTEREST(S)

NORDFORSK (project no: 71450). The Research Fund of Rigshospitalet, Copenhagen University Hospital. ReproUnion Collaborative study, co-financed by the European Union, Interreg V ÖKS. Grants from Swedish state under the agreement between the Swedish government and the county councils, the ALF-agreement (LUA/ALF 70940), Hjalmar Svensson Research Foundation. The Research Council of Norway through its Centres of Excellence funding scheme, project number 262700. None of the authors has any conflicts of interests to declare regarding this study.

TRIAL REGISTRATION NUMBER

ISRCTN11780826.

The effect of Day 3 cell number on pregnancy outcomes in vitrified-thawed single blastocyst transfer cycles

STUDY QUESTION

Does cell number on Day 3 have an impact on pregnancy outcomes in vitrified-thawed single blastocyst transfer cycles?

SUMMARY ANSWER

A low Day 3 cell number (≤5 cells) was independently associated with decreased live birth rate (LBR) during single blastocyst transfer cycles in young women.

WHAT IS KNOWN ALREADY

Day 3 cell number is an effective predictor of IVF success rates when transferring cleavage stage embryos. However, the association between Day 3 blastomere number and pregnancy outcomes after blastocyst transfer is still unknown.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study of 3543 patients who underwent frozen-thawed single blastocyst transfers from January 2013 to June 2018 at a tertiary-care academic medical center.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients were grouped into six groups according to the Day 3 cell number: ≤4 cells, 5 cells, 6 cells, 7 cells, 8 cells and >8 cells. The primary outcome measure was LBR. A logistic regression analysis was performed to explore the independent association between Day 3 blastomere number and LBR after adjustment for some potential confounders.

MAIN RESULTS AND THE ROLE OF CHANCE

In women <35 years old, the LBR varied significantly according to Day 3 cell number, with the rate of 31.2%, 34.4%, 41.9%, 45.1%, 48.1% and 48.2% for the ≤4-cell, 5-cell, 6-cell, 7-cell, 8-cell and >8-cell groups, respectively (P < 0.001). This significant difference was also observed in the high- and low-quality blastocyst subgroups of young women. However, for women ≥35 years old, the rate of live birth was similar between groups. Furthermore, after accounting for confounding factors, the LBR was significantly decreased in the ≤4-cell (adjusted odds ratio (aOR): 0.62, 95% CI: 0.48-0.80, P < 0.001) and 5-cell (aOR: 0.73, 95% CI: 0.57-0.92, P = 0.009) groups as compared to the 8-cell group. Likewise, the blastocysts arising from ≤4-cell (aOR: 0.73, 95% CI: 0.57-0.93, P = 0.010) or 5-cell (aOR: 0.77, 95% CI: 0.61-0.97, P = 0.024) embryos were associated with lower clinical pregnancy rate than those from 8-cell embryos. No significant differences were observed in biochemical pregnancy rate and miscarriage rate.

LIMITATIONS, REASONS FOR CAUTION

A limitation of the current study was its retrospective design. Future prospective studies are needed to confirm our findings.

WIDER IMPLICATIONS OF THE FINDINGS

Our observations suggested that a low Day 3 cell number was related to decreased LBR after blastocyst transfer in young women, which provided vital information for clinicians in selecting blastocyst during IVF treatment.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the National Natural Science Foundation of China (NSFC) (31770989 to Y.W.; 81671520 to Q.C.) and the Shanghai Ninth People's Hospital Foundation of China (JYLJ030 to Y.W.). The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Effect of Day 3 and Day 5/6 Embryo Quality on the Reproductive Outcomes in the Single Vitrified Embryo Transfer Cycles

Objective

To explore the live birth rate and neonatal outcome after single vitrified blastocyst transfer versus single vitrified cleavage-stage embryo transfer at different grades of embryo quality.

Methods

A retrospective cohort study including 6077 single vitrified-thawed embryo transfer cycles was performed in the time-period from January 2013 to December 2018.

Results

After controlling for potential confounding variables, there are 161% increased odds of a live birth after transfer of single good quality embryo at day 5, 152% increased odds of a live birth after transfer of single poor quality embryo at day 5, 60% increased odds of a live birth after transfer of single good quality embryo at day 6 compared with transfer of single good quality embryo at day 3. Results from the generalized estimated equation regression showed significant relationship of unadjusted birth weight with development stage of embryo and embryo quality (good quality embryo on day 5 vs. Good quality embryo on day 3:β=108.55, SE=34.89, P=0.002; good quality embryo on day 6 vs. Good quality embryo on day 3:β=68.80, SE=33.75, P=0.041). However, no significant differences were seen in birth weight between transfer single poor quality embryo on day 5, 6 and transfer single good quality embryo on day 3.

Conclusion

A significant increase in live birth rate and birth weight after transfer of single good quality embryo on day 5 and day 6 compared with transfer of single good quality embryo on day 3 in the vitrified embryo transfer cycles.

Incidence and risk factors for velamentous umbilical cord insertion in singleton pregnancies after assisted reproductive technology

AIM

Assisted reproductive technology (ART) is gaining popularity worldwide. However, it is associated with increased incidence of velamentous umbilical cord insertion (VCI) in the placenta, resulting in adverse perinatal outcomes. This study aimed to identify the risk factors that might affect the incidence of VCI in pregnancies after ART treatment.

METHODS

We retrospectively analyzed the records of 906 singleton pregnancies via ART; all women delivered in our facility. Three ART-related variables and infant sex were examined: (1) fertilization method (conventional in vitro fertilization or intracytoplasmic sperm injection), (2) type of embryo at the time of transfer (fresh or frozen-thawed), (3) developmental stage of embryo at the time of transfer (cleavage stage or blastocyst), and (4) infant sex (male or female). Logistic regression analysis was used to assess the impact of these variables on the incidence of VCI.

RESULTS

Of 906 cases, 55 had VCI (incidence rate, 6.1%). After adjusting for potential confounders, blastocyst stage of development (adjusted odds ratio [aOR]: 4.3, 95% confidence interval [CI]: 1.9-12.7) and female sex (aOR: 2.2, 95% CI: 1.2-3.9) emerged as independent risk factors for the development of VCI. The fertilization method and type of embryo at the time of transfer did not affect the incidence of VCI.

CONCLUSIONS

Blastocyst stage of development and female sex pose a higher risk for developing VCI. Thus, more attention should be paid to pregnancies achieved by blastocyst and with a female fetus to detect VCI proactively and safeguard the health of both mother and fetus/neonate.

Effect of platelet-rich plasma on pregnancy outcomes in infertile women with recurrent implantation failure: a randomized controlled trial

METHODS

This study was directed to assess the efficacy of autologous platelet-rich plasma (PRP) on pregnancy rate in recurrent implantation failure. Between 2016 and 2019, a total of 98 women who unsuccessful to be pregnant after three or more high-quality embryo transfers undergoing frozen-thawed embryo transfer with or without an intrauterine infusion of platelet-rich plasma. Thus, 0.5 ml of platelet-rich plasma at 4-6 times higher concentration than peripheral blood infused intrauterine 48 h before embryo transfer. A control group underwent standard protocol.

RESULTS

There were no significant differences between the two groups in terms of age, body mass index and duration and cause of infertility and total transferred embryos and kind of treatment protocol, but secondary infertility and endometrial thickness 96 h before embryo transfer, was more in the intervention group. The clinical pregnancy (48.3% versus 23.26; p = .001) and ongoing pregnancy (46.7% versus 11.7%; p = .001) and implantation rate (58.3% versus 25%; p = .001) was more significant in the intervention group rather than controls. In conclusion, intrauterine infusion of platelet-rich plasma 48 h before freeze-thawed embryo transfer may have more effectiveness in in vitro fertilization (IVF) outcomes in recurrent implantation failure.

Disposition of embryos from women who only produced morphologically poor embryos on day three

Background

The presence of only morphologically poor embryos (MPEs) on day3 is common in autologous in vitro fertilization (IVF), particularly among p Tel: 886-7-7317123 Ext. 8916. Fax: 886-7-7322915.atients who have advanced maternal age or are poor responders. However, there are limited data regarding the disposition of embryos from patients who only produced MPEs on day3. The present study was designed to investigate the possible benefits of extended culturing MPEs. Try to detect whether the extended culture (day4 or day5 culture) can improve the live birth rate per cycle?

Methods

This retrospective, observational, single-center, cohort study examined 224 IVF/intracytoplasmic sperm injection (ICSI) cycles between January 2010 and June 2015, in which women only produced MPEs on day3. A total of 544 MPEs were analyzed. The defines a day3 embryo as an MPE if it fails to develop to eight cells, blastomeres of equal size, and less than 20% cytoplasmic fragments. Of the 224 cycles, 89 (39.7%) underwent fresh embryo transfer on day3, and 135 (60.3%) underwent extended culture. Of the 135 extended cultures, 54 cycles (40.0%) experienced day4, or day5 embryo transfer, 16 cycles (11.9%) had all embryos frozen, and 65 cycles (48.1%) had total embryo arrest.

Results

Analysis of patient baseline demographic data, cycle characteristics, and cycle outcomes for day3 transfer group and extended culture group indicated that a higher body mass index in the day3 transfer group was the only significant difference (p = 0.006). Both fresh transfer groups had low live birth rates (LBRs) (4.5% vs. 7.4% p = 0.46). After extended culture, 65 cycles (48.1%) were cancelled because the embryos exhibited developmental arrest and 70 cycles (51.9%) grew to day4 or day5. Thirteen frozen embryo transfer (FET) cycles and 22 frozen blastocysts derived from MPEs were thawed. There were more high-quality embryos (p < 0.001), higher implantation rates (IRs) (p = 0.038), and higher LBRs (p = 0.042) for embryos that underwent FET cycles. MPES in extended culture transfer have favorable survival than MPES in day3 transfer.

Conclusion

The extended culture of MPEs in fresh transfer cycles did not increase the LBR. However, younger females with the extended culture of MPEs followed by FET resulted in significantly higher LBRs and may be a feasible strategy to improve outcomes for patients with poor embryo quality. However, day3 embryo transfer may be a better choice if a fresh transfer is unrestricted and avoid the cycle cancellation. Extended culture may decrease to the transfer of developmental potential arrest embryos to patients.

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.

Time-lapse technology for embryo culture and selection

Culturing of human embryos in optimal conditions is crucial for a successful in vitro fertilisation (IVF) programme. In addition, the capacity to assess and rank embryos correctly for quality will allow for transfer of the potentially 'best' embryo first, thereby shortening the time to pregnancy, although not improving cumulative pregnancy and live birth rates. It will also encourage and facilitate the implementation of single embryo transfers, thereby increasing safety for mother and offspring. Time-lapse technology introduces the concept of stable culture conditions, in connection with the possibility of continuous viewing and documenting of the embryo throughout development. However, so far, even when embryo quality scoring is based on large datasets, or when using the time-lapse technology, the morphokinetic scores are still mainly based on subjective and intermittent annotations of morphology and timings. Also, the construction of powerful algorithms for widespread use is hampered by large variations in culture conditions between individual IVF laboratories. New methodology, involving machine learning, where every image from the time-lapse documentation is analysed by a computer programme, looking for patterns that link to outcome, may in the future provide a more accurate and non-biased embryo selection.

Comparative study on the pregnancy outcomes of in vitro fertilization-embryo transfer between patients with different ovarian responses (a STROBE-compliant article)

There have been few studies on large-sample data of cleavage-stage embryo and blastocyst transfers. We compared the pregnancy outcomes of patients with different ovarian responses after the transfer of different numbers of embryos in different developmental stages.Patients were divided into 3 groups including low response group, medium response group, and high response group according to different ovarian responses. Patients in each group were further divided into 4 subgroups including group A: transfer of 1 D3 embryo, group B: transfer of 2 D3 embryos; group C: transfer of 1 D5 blastocyst; and group D: transfer of 2 D5 blastocysts.In low ovarian responders, the implantation rate, clinical pregnancy rate and live birth rate were significantly lower in the group A than in the groups B and C. In medium ovarian responders, the implantation rate was significantly higher, but the multiple pregnancy rate was significantly lower in the group C than in the group B. The multiple pregnancy rate was significantly higher in the group D than in the group C. In high ovarian responders, the implantation rate was significantly lower, but the multiple pregnancy rate was significantly higher in the group B than in group C.Based on the above results, the single blastocyst transfer is preferable for the patients with different ovarian responses.

Birthweight of singletons born after cleavage-stage or blastocyst transfer in fresh and warming cycles

STUDY QUESTION

Does extended culture to the blastocyst stage affect singleton birthweight after either fresh or vitrified-warmed embryo transfer?

SUMMARY ANSWER

Singleton birthweight z-scores did not vary significantly after a fresh blastocyst transfer, whereas the additional effect of vitrification remains inconclusive.

WHAT IS KNOWN ALREADY

Observational studies have associated extended culture with an increased risk of preterm birth and low birthweight. On the contrary, in terms of birthweight and gestational age, singletons born after vitrification have been associated with a better perinatal outcome when compared to those born following a fresh transfer.

STUDY DESIGN, SIZE, DURATION

Our post-hoc cohort analysis on neonatal outcomes included 447 liveborn singletons was derived from a recent retrospective analysis on cumulative live birth rates after cleavage-stage and blastocyst transfers. These babies were born following a fresh single cleavage-stage transfer (FCT Day 3, n = 113), fresh single blastocyst transfer (FBT Day 5, n = 218), vitrified-warmed cleavage-stage transfer (VCT Day 3, n = 58) or vitrified-warmed blastocyst transfer (VBT Day 5, n = 58).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Singleton birthweight was the primary outcome measure. Gestational age and gender of the newborn were accounted for by using birthweight z-scores in a multivariable linear regression analysis, adjusting for other confounders (maternal age, BMI, parity and smoking behaviour). Vanishing twins were excluded from the analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

A significantly lower z-score was observed after blastocyst transfer compared to cleavage-stage transfer in the vitrified-warmed Day 5 group (P = 0.013), a difference not observed in the fresh transfer groups (P = 0.32). Following multivariable regression analysis [adjusted regression coefficient (95% confidence interval)], the FCT and FBT groups showed no significant influence on the birthweight z-scores after fresh transfer [-0.19 (-0.44; 0.05)], but the transfer of vitrified blastocysts (VBT) was associated with a lower birthweight [-0.52 (-0.90; -0.15)] compared with the transfer of vitrified cleavage-stage embryos (VCT).

LIMITATIONS, REASONS FOR CAUTION

The present cohort was relatively small, especially in the vitrified-warmed subgroups. Pregnancy-associated factors possibly influencing birthweight (such as diabetes, hypertension, pre-eclampsia) were also not accounted for in the analysis.

WIDER IMPLICATIONS OF THE FINDINGS

Different ART procedures, including extended culture and vitrification, may hold potential safety issues. These results require further confirmation in future larger studies.

STUDY FUNDING/COMPETING INTEREST(S)

None.

TRIAL REGISTRATION NUMBER

N/A.

Endogenous progesterone levels could predict reproductive outcome in frozen embryo replacement cycles supplemented with synthetic progestogens: A retrospective cohort study

PURPOSE

A retrospective, cohort study was conducted between 2009 and 2017 in a private infertility center to determine the predictive value of endogenous estrogen (E2) and progesterone (P4) levels in hormone-replacement frozen embryo replacement (FER) treatment cycles.

METHODS

A total of 120 consecutive, infertile patients who became pregnant after FER cycles were analyzed (age: 37.4 ± 4.4 years). Electively vitrified blastocysts were created during natural cycle IVF or mild ovarian stimulation treatments and subsequently transferred through delayed vitrified-thawed blastocyst transfer cycles supplemented with estrogens and a combination of synthetic progestogens. Serum E2 and progesterone P4 levels were intensively monitored every five days (from the day after embryo transfer until 9w1d of pregnancy) and compared among patients with a subsequent live birth (n = 76) or first-trimester pregnancy loss (n = 44).

RESULTS

Endogenous placental activity started as early as 5-6th pregnancy week differing significantly according to pregnancy outcome. For P4, the exponential rise from 6w2d onwards allowed distinguishing between failing and successful conceptions. For P4, lower quartiles of the live birth group did not intersect with upper quartiles of the miscarriage group.

CONCLUSIONS

Innovative FER protocols incorporating synthetic progestogens allow the correct measurement of endogenous placental activity and could help to monitor early first-trimester ART pregnancies.

Single fresh blastocyst transfer or single cryopreserved-thawed blastocyst transfer: which is preferable for infertile patients in IVF/ICSI cycles? A meta-analysis

PURPOSES

Nowadays, an increasing number of studies have proposed single embryo transfer (SET), especially single blastocyst transfer (SBT). To compare the clinical outcomes of single fresh blastocyst transfer (BT) and single cryopreserved-thawed BT in patients undergoing in vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI) cycles.

METHODS

The PubMed, Embase, and Cochrane Library databases were searched from the start dates until February 2018. The primary outcomes were clinical pregnancy rate (CPR) and embryo implantation rate (IR). The secondary outcomes were multiple pregnancy rate (MPR), live birth rate (LBR), and miscarriage rate (MR). Using the Mantel-Haenszel random effects model to analyze summary risk ratio (RR) with 95% confidence intervals (CIs). Statistical heterogeneity scores were assessed with the standard Cochrane's Q test and I² statistic.

RESULTS

In total, eight studies (two prospective studies, six retrospective studies) were included in our analysis. There was no statistically significant difference regarding clinical pregnancy (RR = 1.18, 95% CI = 0.91-1.55) and embryo implantation (RR = 1.04, 95% CI = 0.77-1.41). Regarding secondary outcomes, there was no significant difference regarding miscarriage (RR = 0.79, 95% CI = 0.60-1.03) and multiple pregnancy (RR = 1.23, 95% CI = 0.75-2.04). However, single fresh BT is associated with an increased live birth (RR = 1.28, 95% CI = 1.05-1.57) compared with single cryopreserved-thawed BT.

CONCLUSIONS

In summary, this meta-analysis supports the hypothesis that single cryopreserved BT might not be the best choice compared with single fresh BT in patients undergoing IVF/ICSI cycles.

Fresh versus frozen-thawed blastocyst transfer in high responders

OBJECTIVE

This study aimed to investigate and compare the pregnancy and live birth rates in IVF cycles of frozen-thawed embryo transfers and fresh embryo transfers in a group of women with a high risk of Ovarian hyperstimulation syndrome (OHSS).

MATERIAL AND METHODS

The study group consisted of 254 women with a high level of response to controlled ovarian hyperstimulation. The patients who received fresh cycle embryo transfers with calcium infusions are referred to as the Fresh Ca+ group, and those without the calcium therapy are called the Fresh Ca- group; and we used correspondingly similar terminology for the Frozen group.

RESULTS

We observed no statistically significant differences between the cycles of fresh and frozen-thawed embryo transfers in patients with a high risk of OHSS in terms of implantation, clinical pregnancy, and live birth rates. Furthermore, these implantation, clinical pregnancy and live birth rates were not different in the cycles with or without calcium treatment. There was no statistical difference in the OHSS rates between the fresh and frozen-thawed cycles; although, the OHSS rates were less in the two calcium infusion groups (Fresh Ca+ and Frozen-thawed Ca+) than in the without-calcium group. There was no OHSS development in the subjects of the Frozen-thawed Ca+ group.

CONCLUSION

Our study results suggest that fresh and frozen-thawed embryo transfers have similar IVF results in patients with a high risk of OHSS. Calcium infusion is beneficial in preventing OHSS without altering pregnancy rates. Both IVF protocols with calcium infusion can safely be applied in high-responder patients without lowering success rates.

No influence of the indication of freeze-all strategy on subsequent outcome to frozen-thawed embryo transfer cycle

BACKGROUND

Freezing all embryos generated during an IVF/ICSI attempt is used increasingly as a strategy to optimize results. We investigated whether we could find differences in outcome between subpopulations of patients undergoing the so-called "freeze all" procedure.

METHODS

Non-interventional, observational, retrospective study of 131 freeze-all cycles performed between July 2015 and December 2016 at the University Hospital of Ghent (Belgium). Freeze-all indications were categorized in 4 groups: group 1, high progesterone level (PE) on the day of hCG administration defined as >1.5 ng/ml (n= 50); group 2, risk of Ovarian Hyperstimulation Syndrome (OHSS) (n=38); group 3, partner donation in lesbian couples (n=23) and group 4, a miscellany of other reasons (n=20). Clinical pregnancy with fetal heart beat after the first thawed embryo transfer (ET) after ovum pick-up and cumulative clinical pregnancy rate per attempt were used as primary outcome variables.

RESULTS

Clinical pregnancy rate (CPR) with fetal heart beat in the first thawed ET and cumulative clinical pregnancy rate per cycle (CCPR) were not statistically different between the four groups. In the group of PE a cumulative clinical pregnancy rate was observed of 40,5%, this in comparison to the 3 other groups involving risk of OHSS (66,7%), partner donation (61,1%) and other reasons (57,1%). More rFSH was used in the group with Progesterone elevation (PE) (P=0.04), as described earlier in the literature.

CONCLUSION

Our findings indicate comparable (cumulative) clinical pregnancy rates per attempt between the four groups of freeze-all indications.

The impact of single versus double blastocyst transfer on pregnancy outcomes: A prospective, randomized control trial

OBJECTIVE

To determine if elective single blastocyst transfer (e-SBT) compromises pregnancy outcomes compared to double blastocyst transfer (DBT) in patients with favorable reproductive potential.

METHODS

This Randomized Control Trial included 50 patients with SBT (Group 1) and 50 patients with DBT (Group 2). All women were <35 years and had favorable reproductive potential. Randomization criterion was two good quality blastocysts on day 5. Patients who did not get pregnant or who miscarried underwent subsequent frozen cycles with transfer of two blastocysts (if available) in both groups.

RESULTS

No significant difference was observed in the majority of the demographic data, infertility etiology, ovarian stimulation characteristics and embryology data between the two groups. There was a significantly lower clinical pregnancy (61.2% vs 80.0%), and delivery (49.0% vs 70.0%) rates, but no difference in implantation (59.2% vs 54.0%), miscarriage, or ectopic pregnancy rates between Group 1 and Group 2, respectively. There was a significantly higher multiple pregnancy rate in Group 2 (35.0%) compared to Group 1 (0%) [P=0.000]. When fresh and first frozen cycles were combined, there was a significantly lower cumulative clinical pregnancy (77.6% vs 96.0%, P=0.007) and delivery (65.3% vs 86.0%, P=0.016) rates in Group 1 compared to Group 2 respectively.

CONCLUSIONS

In patients with favorable reproductive potential, although e-SBT appears to reduce clinical pregnancy and live-birth rates, excellent pregnancy outcomes are achieved. Clinicians must weigh the benefits of DBT against the risk associated with multiple pregnancies in each specific patient before determining the number of blastocysts to be transferred.

Effects of endometrial injury on frozen-thawed blastocyst transfer in hormone replacement cycles

Aim

To evaluate whether local endometrial injury would improve the pregnancy rates after frozen‐thawed blastocyst transfer in cycles with hormone replacement.

Methods

Seventy‐seven patients who were aged <40 years with a history of at least three unsuccessful embryo transfers and who underwent frozen‐thawed blastocyst transfer during hormone replacement cycles between February and June, 2013 were studied. They were allocated into two groups based on the last digit of their clinical record number: an experimental group (n=22), excluding patients who withheld consent or who were unable to undergo treatment, and a control group (n=55). In the experimental group, the endometrium was scratched once with an endometrial sampler during the luteal phase of the cycle preceding the embryo transfer.

Results

There was no significant difference in the baseline characteristics between the groups. The clinical pregnancy rate was 6% in the experimental group and 22% in the control group. Among these, the ongoing pregnancy rate was 100% in the experimental group and 50% in the control group.

Conclusion

Endometrial injury might increase the pregnancy rates after frozen‐thawed blastocyst transfer and decrease the risk of miscarriage in patients with a history of unsuccessful embryo transfers.

Effect of premature serum progesterone rise on embryo transfer outcomes and the role of blastocyst culture and transfer in assisted reproductive technology cycles with premature progesterone rise

OBJECTIVE

In 1991, researchers reported that a modest preovulatory increase in serum progesterone levels is associated with lower pregnancy rates and higher incidence of pregnancy loss in in vitro fertilization (IVF). We wonder whether embryo transfer (ET) in assisted reproductive technology (ART) cycles in patients with premature progesterone rise (PPR) have a negative impact on the clinical pregnancy rates (CPRs) and/or live birth rates (LBRs) in our series. Consequently, will blastocyst transfer reverse the negative impact?

MATERIALS AND METHODS

This noninterventional, retrospective, observational tertiary center study was conducted between January 2010 and December 2012. All fresh ET cycles with serum progesterone levels measured (n = 599) on the day of hCG administration were analyzed.

RESULTS

Sera lutenizing hormone (LH), E2, and progesterone (P) were measured and analyzed. The CPRs of cycles in patients with p ≤ 1.5 ng/mL (low) versus those with p > 1.5 ng/mL (high) were 37.04% versus 41.03% [odds ratio (OR) = 1.18, 95% confidence interval (CI): 0.728-1.920; p = 0.50). The LBRs of cycles in patients with low progesterone level versus those with PPR were 30.52% versus 34.62% (OR = 1.21, 95% CI: 0.729-1.992; p = 0.47). No statistically significant association was detected. We further analyzed the outcomes according to different stages of ET and found that blastocyst (D5) ET significantly increase the LBRs as compared with cleavage stage (D2/D3) ET in the PPR group (44.44% versus 21.43%; p = 0.043).

CONCLUSION

PPR did not significantly compromise the clinical outcomes in this series. However, shifting to blastocyst transfer probably could increase the live birth in cycles with PPR.

Preimplantation genetic screening: who benefits?

OBJECTIVE

To compare IVF outcomes between women undergoing frozen transfers of blastocysts verified as euploid by preimplantation genetic screening (PGS) with patients undergoing fresh nonbiopsied blastocyst transfers.

DESIGN

Retrospective cohort study.

SETTING

Academic medical center.

PATIENT(S)

All patients undergoing IVF-PGS cycles between January 2010 and November 2014 were included (n = 274). Patients were compared with a control group consisting of all fresh blastocyst transfers that occurred during the same period (n = 863).

INTERVENTION(S)

Patients underwent IVF-PGS with 24-chromosome screening. Patients with euploid embryos had transfer of one to two embryos in a subsequent frozen ET cycle.

MAIN OUTCOME MEASURE(S)

Implantation, clinical intrauterine gestation (CIG), miscarriage, biochemical pregnancy (BC), and live birth (LB) rates were compared.

RESULT(S)

Odds ratios (ORs) were estimated for outcomes in women undergoing PGS versus controls. Among patients ≤37 years old, there were no differences in CIG and LB rates for single (adjusted ORs [aORs], 1.20 [95 %confidence interval {CI}, 0.66-2.21]; 1.21 [95% CI, 0.66-2.2]) and double ETs (aORs, 1.09 [95% CI, 0.54-2.18]; 0.87 [95% CI, 0.44-1.7]). BC and miscarriage rates were also similar. For patients >37 years old, CIG and LB rates were increased for single (aORs, 3.86 [95% CI, 1.25-11.9]; 8.2 [95% CI, 2.28-29.5]) and double ETs (aORs, 9.91 [95% CI, 2.0-49.6]; 8.67 [95% CI, 2.08-36.2]) with no difference in BC and miscarriage rates. A per-retrieval analysis of the >37 group failed to demonstrate any difference in CIG or LB rates.

CONCLUSION(S)

Among patients ≤37, IVF-PGS does not improve CIG, LB, and miscarriage rates. IVF-PGS in women >37 improved CIG and LB rates. However, per cycle, the PGS advantage in this age group does not persist.

Freeze-all at the blastocyst or bipronuclear stage: a randomized clinical trial

OBJECTIVE

To compare outcomes for patients randomized to have all embryos cryopreserved at the blastocyst stage or at the bipronuclear stage with subsequent post-thaw culture to the blastocyst stage.

DESIGN

Randomized controlled trial.

SETTING

Private fertility center.

PATIENT(S)

This study included 140 women, age 18-40 years, with at least eight antral follicles, and day 3 FSH <10 IU/L undergoing IVF.

INTERVENTION(S)

After oocyte retrieval, subjects were randomized to have entire embryo cohorts cryopreserved at either the bipronuclear stage (2PN Cryo group) or at the blastocyst stage (Blast Cryo group).

MAIN OUTCOME MEASURE(S)

Ongoing pregnancy (viable fetal heart motion at 10 weeks' gestation) per oocyte retrieval through the first transfer attempt.

RESULT(S)

No significant differences were observed between the two study groups in age at retrieval, body mass index, antral follicle count, day 3 FSH level, or IVF cycle parameters. No significant differences were observed in ongoing pregnancy rate per retrieval (62.0%; 95% confidence interval [CI], 50.3%-72.4%) in the 2PN Cryo group; and 55.1%; 95% CI, 42.6%-67.1% in the Blast Cryo group), implantation rate (60.0% vs. 62.7%), ongoing pregnancy rate per thaw (62.0% vs. 59.4%), ongoing pregnancy rate per transfer (67.7% vs. 69.1%), and the cumulative ongoing pregnancy rate per retrieval from all thaws to date of embryos derived from the study retrieval cycle (64.8% vs. 60.9%).

CONCLUSION(S)

Freeze-all at the blastocyst stage or at the bipronuclear stage has similar efficacy and IVF outcomes. The choice between them may depend primarily on logistical factors.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01247987.

Intrauterine administration of human chorionic gonadotropin does not improve pregnancy and life birth rates independently of blastocyst quality: a randomised prospective study

BACKGROUND

Successful embryo implantation depends on a well-timed maternal-embryonic crosstalk. Human chorionic gonadotropin (hCG) secreted by the embryo is known to play a key role in this process and to trigger a complex signal transduction cascade allowing the apposition, attachment, and invasion of the embryo into the decidualized uterus. Production of hCG was reported to be dependent on blastocyst quality and several articles suggested that intrauterine hCG injection increases pregnancy and implantation rates in IVF patients. However, no study has as yet analysed birth rates as final outcome. Our objective was to determine whether clinical outcome after blastocyst transfer can be improved by intrauterine injection of hCG and whether this is dependent on blastocyst quality.

METHODS

A prospective randomised study was conducted in two settings. In cohort A, hCG application was performed two days before blastocyst transfer. In cohort B, the administration of hCG occurred just prior to embryo transfer on day 5. For both cohorts, patients were randomised to either intrauterine hCG application or to the control group that received culture medium. Clinical outcome was analysed according to blastocyst quality of transferred embryos.

RESULTS

The outcome of 182 IVF-cycles (cohort A) and 1004 IVF-cycles (cohort B) was analysed. All patients received a fresh autologous blastocyst transfer on day five. Primary outcomes were pregnancy rates (PR), clinical pregnancy rates (cPR), miscarriage rates (MR), and live birth rates (LBR). No improvement of clinical outcome after intrauterine hCG administration on day 3 (cohort A) or day 5 (cohort B) was found, independently of blastocyst quality transferred. The final outcome in cohort A: LBR after transfer of top blastocysts was 50.0 % with hCG and 53.3 % in the control group. With non-top blastocysts, LBR of 17.1 % (hCG) and 18.2 % (control) were observed (n.s.). In cohort B, LBR with top blastocysts was 53.3 % (hCG) and 48.4 % (control), with non-top blastocysts it came to 28.7 % (hCG) and 35.0 % (control). The differences between the groups were statistically not significant. Furthermore, we investigated a possible benefit of hCG administration in correlation with female age. In both age groups (<38 years and ≥ 38 years) we found similar LBR after treatment with hCG vs. medium. A LBR of 47.1 % vs. 48.7 % was obtained in the younger group and 26.6 % vs. 30.8 % in the older group.

CONCLUSIONS

In contrast to previous studies indicating a substantial benefit from intrauterine hCG application in cleavage stage embryo transfers, in our study we could not find any evidence for improvement of clinical outcome in blastocyst transfer cycles, neither with top nor with non-top quality morphology.

Extended embryo culture is not associated with increased adverse obstetric or perinatal outcome

OBJECTIVE

We sought to compare obstetric and perinatal outcomes of singletons born after extended embryo culture and a single blastocyst stage embryo vs a single cleavage stage embryo transfer.

STUDY DESIGN

This was a retrospective cohort study of 1543 fresh single embryo transfers using nondonor oocytes in women ≤40 years old from December 2008 through December 2012 at the reproductive unit of McGill University Health Center. The main outcome measures were perinatal outcomes including birthweight, low birthweight, small for gestational age, preterm delivery, preeclampsia, placental abruption, and neonatal complications. Covariates were maternal age, body mass index, smoking, cause of infertility, parity, and sex of the baby.

RESULTS

Transfers of 693 fresh single cleavage embryos and 850 fresh single blastocysts resulting in 564 pregnancies and 381 singleton deliveries were analyzed. Blastocyst transfer resulted in a higher clinical pregnancy rate (50.1% and 19.9%) and live birth rate (33.5% and 13.8%) compared to cleavage embryo transfer, respectively (P < .001). Multivariate analyses for pregnancy revealed no increased risk of maternal or neonatal complications in pregnancies resulting from extended embryo culture.

CONCLUSION

Live births resulting from extended embryo culture and a single blastocyst transfer are not associated with increased adverse obstetric and perinatal outcome compared to live births from a single cleavage embryo transfer in women ≤40 years old.

Effect of in vitro culture period on birthweight of singleton newborns

STUDY QUESTION

Does prolonged in vitro culture influence newborn birthweight?

SUMMARY ANSWER

The absolute mean birthweight and gestational age- and gender-adjusted birthweight (Z scores) of singletons born from blastocyst transfer are higher than singletons born from Day 3 transfer.

WHAT IS KNOWN ALREADY

An increased proportion of large-for-gestational age (LGA) newborns occurs after blastocyst transfer compared with Day 2 transfer, and Z scores for newborns after blastocyst transfer are higher than newborns after transfer on Day 2 or Day 3.

STUDY DESIGN, SIZE AND DURATION

This study was a retrospective analysis of newborn birthweight, including 2929 singletons at the Reproductive Medical Center of Peking University Third Hospital between January 2009 and June 2012. The number of singletons after Day 3 transfer was 2833 and the number of singletons after blastocyst transfer (Day 5-6) was 96.

PARTICIPANTS/MATERIALS, SETTING, AND METHODS

Only cycles with fresh embryo transfer were included. Patients ≤40 years of age with a BMI < 30 kg/m(2) were analyzed. Only data from singleton newborns born alive after the 20th week of gestation were included in the data analysis. Patients with more than one fetal sac diagnosed by ultrasound but who delivered singletons were excluded. Patients who received PGD and cycles with donor oocytes were excluded. Multiple linear regression analysis was performed to determine the significance of individual factors on absolute birthweight of singleton newborns. The absolute birthweight and Z scores of singletons were compared.

MAIN RESULTS AND THE ROLE OF CHANCE

Multiple linear regression analysis indicated that maternal age, maternal BMI, paternal BMI, type of infertility, gestational age, infant gender and culture period were significantly associated with birthweight. The absolute birthweight for singletons resulting from blastocyst transfer was significantly greater than singletons resulting from Day 3 transfer (3465.31 ± 51.36 versus 3319.82 ± 10.04 g respectively, P = 0.009). The Z scores for singletons after blastocyst transfer were significantly higher than singletons after Day 3 transfer (0.347 versus 0.029 respectively, P = 0.016).

LIMITATIONS AND REASONS FOR CAUTION

In our clinic, blastocyst culture is mainly offered to patients with unsuccessful IVF cycles but also to patients with uterine malformations, and therefore this protocol introduced a potential selection bias in our study. Moreover, as certain culture media are associated with fetal overgrowth, the media used may be also a confounding factor, even though the absolute birthweights of singletons were comparable.

WIDER IMPLICATIONS OF THESE FINDINGS

Our study suggests that a prolonged (5-6 days) in vitro culture period has a significant effect on the mean absolute birthweight and Z scores of singleton newborns. The effect of prolonged in vitro culture on epigenetic changes in the embryo needs further study.

STUDY FUNDING/COMPETING INTEREST(S)

National Natural Science Foundation of China for Young Scholars (81300483). The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

Not applicable.

Factors associated with monozygosity in assisted reproductive technology pregnancies and the risk of recurrence using linked cycles

OBJECTIVE

To evaluate factors associated with monozygosity (MZ) (number of fetal heartbeats on early ultrasound greater than the number of embryos transferred) and the risk of recurrence in subsequent pregnancies using a national assisted reproduction database.

DESIGN

Historical cohort study.

SETTING

Clinic-based data.

PATIENT(S)

197,327 pregnancies (including 2,824 with evidence of MZ) from cycles reported to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System (SART CORS) between 2004 and 2010.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Evidence of MZ, adjusted odds ratios and their 95% confidence intervals computed from logistic regression models.

RESULT(S)

In the univariate analysis, the risk of MZ was increased with ovulation disorders, donor oocytes, gonadotropin-releasing hormone agonist (GnRH-a) suppression, assisted hatching (AZH), and day 5-6 transfer, and was decreased with higher follicle-stimulating hormone (FSH) doses (≥3,000 IU). In the multivariate analysis, the risk of MZ was increased with GnRH-a suppression, AZH, and decreased with intracytoplasmic sperm injection (ICSI) and higher FSH dose. The interaction showed that although MZ was more likely with day 5-6 embryos, AZH had a minimal nonsignificant effect, whereas in day 2-3 embryos, AZH had a substantial statistically significant effect. Only one woman had a recurrence of MZ in a subsequent assisted reproduction pregnancy, which is consistent with randomness.

CONCLUSION(S)

The risk of MZ was higher with fresh day 5-6 embryos, donor oocytes, GnRH-a suppression, lower FSH doses, and AZH (particularly with day 2-3 embryos).

Melatonin promotes the in vitro development of pronuclear embryos and increases the efficiency of blastocyst implantation in murine

When a defect occurs in the in vitro development of a pronuclear embryo, the interruption of the subsequent implantation limits the success of assisted conception. This common problem remains to be solved. In this study, we observed that melatonin at its physiological concentration (10(-7)  m) significantly promoted the in vitro development of murine pronuclear embryos. This was indicated by the increased blastocyst rate, hatching blastocyst rate, and blastocyst cell number with melatonin treatment. In addition, when these blastocysts were implanted into female recipient mice, the pregnancy rates (95.0% versus control 67.8%), litter sizes (4.1 pups/litter versus control 2.7 pups/litter), and postnatal survival rates of offspring (96.84% versus control 81.24%) were significantly improved compared with their non-melatonin-treated counterparts. Mechanistic studies revealed that melatonin treatment upregulates gene expression of the antioxidant enzyme, superoxide dismutase (SOD), and the anti-apoptotic factor bcl-2 while downregulating the expression of pro-apoptotic genes p53 and caspase-3. Due to these changes, melatonin treatment reduces ROS production and cellular apoptosis during in vitro embryo development and improves the quality of blastocysts. The implantation of blastocysts with higher quality leads to more healthy offspring and increased pup survival.

Bivariate analysis of basal serum anti-Müllerian hormone measurements and human blastocyst development after IVF

BACKGROUND

To report on relationships among baseline serum anti-Müllerian hormone (AMH) measurements, blastocyst development and other selected embryology parameters observed in non-donor oocyte IVF cycles.

METHODS

Pre-treatment AMH was measured in patients undergoing IVF (n = 79) and retrospectively correlated to in vitro embryo development noted during culture.

RESULTS

Mean (+/- SD) age for study patients in this study group was 36.3 ± 4.0 (range = 28-45) yrs, and mean (+/- SD) terminal serum estradiol during IVF was 5929 +/- 4056 pmol/l. A moderate positive correlation (0.49; 95% CI 0.31 to 0.65) was noted between basal serum AMH and number of MII oocytes retrieved. Similarly, a moderate positive correlation (0.44) was observed between serum AMH and number of early cleavage-stage embryos (95% CI 0.24 to 0.61), suggesting a relationship between serum AMH and embryo development in IVF. Of note, serum AMH levels at baseline were significantly different for patients who did and did not undergo blastocyst transfer (15.6 vs. 10.9 pmol/l; p = 0.029).

CONCLUSIONS

While serum AMH has found increasing application as a predictor of ovarian reserve for patients prior to IVF, its roles to estimate in vitro embryo morphology and potential to advance to blastocyst stage have not been extensively investigated. These data suggest that baseline serum AMH determinations can help forecast blastocyst developmental during IVF. Serum AMH measured before treatment may assist patients, clinicians and embryologists as scheduling of embryo transfer is outlined. Additional studies are needed to confirm these correlations and to better define the role of baseline serum AMH level in the prediction of blastocyst formation.

Elective cryopreservation of all day 5 blastocysts is more effective than using day 6 blastocysts for improving pregnancy outcome in stimulated cycles

Aim:  To evaluate the efficacy of cryopreservation of all blastocysts for future transfers in stimulated cycles. Methods:  We carried out fresh blastocyst transfer cycles on day 5 (n = 290) or day 6 (n = 119) and thawed blastocyst transfer cycles that were frozen on day 5 (n = 136), day 6 (n = 71) or day 6 electively (n = 21). We retrospectively compared the clinical outcome of fresh blastocyst transfers with thawed blastocyst transfers according to the day of blastocyst transfer or freezing. Results:  The clinical implantation rates in women with stimulated cycles were significantly higher after the transfer of thawed blastocysts compared with the transfer of fresh blastocysts (day 5, P < 0.0005; day 6, P < 0.00005). Although the implantation rate of fresh day 6 transfer cycles was lower than that of elective day 6 frozen-thawed cycles, this difference was not statistically significant (P = 0.17). Conclusions:  Thawed blastocysts demonstrated a better potential for implantation when compared with fresh blastocysts in stimulated cycles. We concluded that elective cryopreservation of all blastocysts on day 5 is an effective option to improve the clinical outcome in stimulated cycles. Additionally, with cryopreservation of all day 6 blastocysts, the implantation rates of first embryo transfers may increase by allowing the best-quality blastocysts to be transferred in thawed cycles. (Reprod Med Biol 2008; 7: 75-83).

Elective single embryo transfer: Comparison of blastocyst and cleavage-stage embryo transfer

Objective:   Blastocysts are reportedly suitable for preventing multiple pregnancies as a result of the high implantation rate per embryo. The present study compared clinical results for elective single embryo transfer (ET) between blastocysts and cleavage-stage embryos in order to ascertain the usefulness of blastocyst culturing in single ET. Methods:   Between January 2002 and December 2004, conventional in vitro fertilization ET and/or intracytoplasmic sperm injection was carried out for single ET in 86 cycles, to prevent multiple pregnancies (for medical reasons or because of patient wishes). Results:   Among the 80 cycles in which a fresh embryo was transferred, pregnancy/implantation rates per ET were 35.3% for day 2/3 ET and 50.0% for day 5 ET, and pregnancy/implantation rates per oocyte retrieval were 35.3% for day 2/3 ET and 44.2% for day 5 ET. Ongoing pregnancy/delivery rates per oocyte retrieval were 32.4% for day 2/3 ET and 38.5% for day 5 ET. Monozygotic twinning occurred in one case of day 5 ET. Conclusions:   Pregnancy rates per single ET tended to be higher for day 5 ET than for day 2/3 ET. However, no marked differences were identified in ongoing pregnancy/delivery rates per oocyte retrieval between groups. (Reprod Med Biol 2005; 4: 197-201).

Pregnancy rate, multiple pregnancy rate, and embryo quality: Clues for single blastocyst transfer from double blastocyst transfer in an unselected population

Objective:  Minimizing multiple pregnancy is a priority in assisted reproduction. As implantation rates are critical to success and reduce multiple pregnancy, we investigated whether blastocyst grade determined implantation rate following double blastocyst transfer in unselected cases. Materials and Methods:  We studied 69 three-cleavage stage embryo transfers and 64 two-blastocyst transfers. Two blastocysts, or one when two blastocysts were not available, were transfered after evaluating the grade of blastocysts. The difference in pregnancy and implantation rates to patient age, the number of retrieved oocytes and grade of blastocysts were analyzed. Results:  Blastocyst and grade 3AA rates per fertilized egg were 50.3% and 26.0%, respectively. Following two-blastocyst transfer, pregnancy rate per transfer, implantation rate per embryo, and multiple pregnancy rate per pregnancy were 39.1%, 26.5%, and 24.0%, respectively. Two-blastocyst transfer achieved implantation more often than three-cleavage-stage embryo transfer, but did not reduce multiple pregnancy. Pregnancy, implantation, and multiple pregnancy rates did not reflect maternal age. Higher pregnancy and implantation rates per transfer were attained for with six or more oocytes retrieved or transfer of two-blastocyst graded 3AA or higher especially when two or more blastocysts graded 3AA or higher are available, but the latter showed a high multiple pregnancy rate (38.5%). Conclusions:  Single embryo transfer could be carried out when two or more blastocysts of grade 3AA or higher have been developed. (Reprod Med Biol 2005; 4: 153-160).

The influences of weather on patients with different ovarian responses in the treatment of assisted reproductive technology

PURPOSE

The purpose of this study was to evaluate the influences of tropical weather on patients with different ovarian responses in the treatment of assisted reproductive technology.

METHODS

Six-hundred fourty-seven women underwent their first treatment cycles were retrospectively analyzed. Patients received embryo transfer either 3 days or 5 days after oocyte retrieval, depending on the number and quality of embryos on day-2.

RESULTS

Significant correlations were demonstrated in the top quality embryo rates of day-3 and day-5 embryo transfers with temperature, humidity, and atmosphere pressure. The cumulative light hours negatively correlated with the implantation and pregnancy rates of day-3 embryo transfer (-.282 and -.282, respectively), while they positively correlated with those of day-5 embryo transfer (.225 and .224, respectively).

CONCLUSIONS

These results clearly suggest that weather may exert influences on the outcome of assisted reproductive technology. Patients with different ovarian responses or blastocyst culture and transfer may modify weather influences.

Selected single blastocyst transfers maintained pregnancy outcome and eliminated multiple pregnancies

Background:  Transfer of more than one embryo following in vitro fertilization/intracytoplasmic sperm injection cycles have increased pregnancy rate at the cost of increasing the incidence of triplets and twins. It has been proposed that prolonged culture to the blastocyst stage would automatically result in the selection of good quality embryos for transfer and minimize the incidence of triplets and twins. Methods and Results:  The objectives of the present retrospective analysis were to examine the pregnancy outcome, multiple pregnancy and related data following: (i) single blastocyst transfer (BT) and double BT; (ii) single BT in patients belonging to different age groups; and (iii) good, fair or poor quality of BT. A total of 260 BT were carried out between August 1998 and July 2002 and they are included in the current study. Sixty of the 260 BT patients received a single BT, and 41 of them received selected single good quality BT (SSBT). The implantation rate has no significant difference between following single BT (53.3%) and double BT (42.8%). No multiple pregnancy occurred following single BT, while significantly higher (P < 0.05) multiple pregnancy rate was observed following a double BT (45.8%). The clinical pregnancy and implantation rates following a single BT were similar (P > 0.05) in patients belonging to <30 years (62.5%), 30-34 years (57.9%) and 35-39 years old (35.8%). Conclusion:  Selected single good quality BT maintained pregnancy and avoided multiple pregnancies. It is recommended for patients with a risk for high-order multiple pregnancy. (Reprod Med Biol 2004; 3: 13-18).

Comparison of the sex ratio with blastocyst transfer and cleavage stage transfer

PURPOSE

To evaluate the sex ratio in births conceived with blastocyst transfer compared to day 3-ET.

METHODS

A retrospective analysis of IVF patients who became pregnant after blastocyst or cleavage stage transfer at Stanford University Hospital and a literature review were performed.

RESULT(S)

In the day 3-ET group, the male-to-female (M/F) ratio was 157/139 (53%/47%) compared to 97/66 (59.5%/40.5%) in the blastocyst group (P = 0.18). Similar trends have been found in individual studies in the literature but reached statistical significance in only one out of six reports reviewed. The combined data from our study and the literature show a male-to-female ratio of 797/594 (57.3%/42.7%) in blastocyst transfer compared to 977/932 (51.2%/48.8%) in day 3-ET (P = 0.001).

CONCLUSION(S)

Although individual studies may lack power to show an altered sex ratio with blastocyst transfer, the combined data presented in this report do suggest that the M/F ratio is higher with blastocyst transfer compared to cleavage stage transfer.

Successful elective single blastocyst transfer in a patient with prior repetitive high-order multiple gestations

Multiple gestations remain one of the leading causes of morbidity related to infertility therapy. In the realm of assisted reproductive technologies, multiple gestations can be significantly limited by the reduction in the number of embryos transferred. Significant concern remains that a reduction in the number of embryos transferred may appreciably lower overall chances for pregnancy. Promising new developments are unfolding that may permit improved detection of a single human embryo with high implantation potential. One such development is the use of sequential culture media to allow prolonged culture of embryos to the blastocyst stage. We report a case in which sequential culture and elective transfer of one blastocyst was successfully used in a patient with a profoundly poor obstetrical history because of the complications of high-order multiple gestations.

Alternative embryo transfer on day 3 or day 5 for reducing the risk of multiple gestations

PURPOSE

This study was carried out to reduce the possibility of high-order multiple gestations and the failure of embryo transfer by determining their replacement date based on the number and quality of 2-day embryos.

METHODS

All zygotes were cocultured with cumulus cells in 10 microliters of YS medium containing 10% human follicular fluid (hFF) for 48 or 96 hr. In period I, all embryos were transferred on day 3 (1032 cycles). In period II, the embryos were transferred on either day 3 or day 5 by determining their replacement date based on the number and quality of 2-day embryos: there were 2701 patients in whom embryos were replaced on day 3 (in the case that the number of zygotes was less than eight and the number of good-quality embryos was less than three) and 1952 patients less than 40 years old in whom embryos were replaced on day 5 (in the case that the number of zygotes was eight or more and/or the number of good-quality embryos was three or more). On the other hand, patients who were 40 years old or more were alloted to day 3 transfer cycles, regardless of the number and quality of the 2-day embryos, due to the possibility of their not producing blastocyst-stage embryos in vitro.

RESULTS

The number of embryos transferred in period II was 2.9 +/- 0.6, while that in period I was 3.7 +/- 0.5. The multiple pregnancy rate was significantly decreased in period II (30.7%) compared to that (49.6%) in period I, while the pregnancy and implantation rates in period II (36.1 and 16.4%, respectively) were not lower than those (34.9 and 16.1%, respectively) in period I. The rate of triplet or more gestations was significantly minimized in period II (2.3%) compared to that in period I (26.5%).

CONCLUSIONS

We propose that determination of the date on which embryos should be transferred based on the number and quality of embryos on day 2 may help to maintain an acceptable pregnancy rate, while minimizing embryo transfer failure and high-order multiple gestations.

Blastocyst-ET and monozygotic twinning

PURPOSE

To examine the rate of monozygotic twinning associated with blastocyst transfer using commercially available, cell-free culture systems with unmanipulated blastocysts.

METHODS

A retrospective analysis was conducted in multiple private and academic infertility centers throughout the United States, of 199 pregnant patients following in vitro fertilization (IVF) blastocyst embryo transfer (ET). Human embryos obtained through standard IVF stimulation protocols were cultured in commercially available, cell-free media systems and transferred as blastocysts. The main outcome measure was the rate of monozygotic twinning.

RESULTS

A total of 199 blastocyst-ET pregnancies were achieved during the study period at the fertility centers examined. Monozygotic twinning was noted in 10/199 (5%) of these pregnancies. All were monochorionic diamnionic.

CONCLUSIONS

Monozygotic twinning previously has been reported following IVF, especially in relation to assisted hatching. While blastocyst transfer has been available for many years using coculture, there have been no published multicenter reports of monozygotic twinning associated with unmanipulated blastocysts. In a multicenter analysis, a definite increase in monozygotic twinning was seen following blastocyst-ET. We believe this phenomenon is real and that this information should be considered when counseling patients for treatment.