Freeze-all cycle for all normal responders?

Effect of estrogen exposure on pregnancy outcomes in artificial frozen-thawed embryo transfer cycles

In contemporary times, the employment of vitrification freezing technology has led to the widespread adoption of frozen-thawed embryo transfer (FET) worldwide. Meanwhile, hormone replacement therapy (HRT) is a crucial protocol for priming the endometrium during FET cycles. Estrogen is required in HRT cycles for the induction of progesterone receptors and to promote endometrial thickness. However, there is no universal consensus on the treatment duration, dosage regimen, administration route, and target serum estrogen levels. Therefore, this study aimed to offer a comprehensive review of these topics. A shorter duration of estrogen exposure may elevate the risk of early miscarriage, while prolonged exposure to estrogen does not seem to confer advantages to general population and may be attempted in individuals with thin endometrium. Moreover, excessive estrogen levels on the day of progesterone administration may be associated with higher miscarriage rates and lower live birth rates (LBR). To offer more comprehensive guidance for clinical practice, extensive and prospective studies involving a large sample size are warranted to determine the optimal concentration and duration of estrogen exposure.

Freeze-all policy versus luteal phase support with low dose of human chorionic gonadotrophin for high-responder patients undergoing intracytoplasmic sperm injection on pregnancy outcomes: a retrospective cohort observational study

Background

The literature has always controversies on the use of freeze-all policy in high-responder women performing intracytoplasmic sperm injection. In this article, we discuss the benefits of freeze-all policy on the incidence of pregnancy outcomes and the complications.

The main body of abstract

Freeze-all policy is applied to the intracytoplasmic sperm injection program by freezing of all embryos and delaying embryo transfer to another subsequent ovarian cycle, to decrease the incidence of ovarian hyperstimulation syndrome, especially in high-responder women. Unfortunately, freeze-all policy is correlated with an increase in the economic costs and more ICSI laboratory effort. Delayed embryo transfer (ET) is correlated with more anxiety among the patients. An alternative strategy is to perform fresh embryo transfer with more intensive luteal phase support to compensate for the negative effect of the GnRH agonist on the endometrial receptivity and luteal phase support.

Short conclusion

The freeze-all policy had better pregnancy rates with less incidence of moderate to severe hyperstimulation syndrome compared with original fresh embryo transfer in high-responder women performing intracytoplasmic sperm injection.

Fresh or Frozen Embryo Transfer in The Antagonist In Vitro Fertilization Cycles: A Retrospective Cohort Study

BACKGROUND

Gonadotropin-releasing hormone antagonist (GnRH-ant), widely adopted protocol, is more in line with the physiological processes, and induces a shorter and more cost-effective ovarian stimulation. In order to assess the success rate of embryo transferring (ET) in the antagonist in vitro fertilization (IVF) cycles, we compared the fresh ET with the frozen ET outcomes.

MATERIALS AND METHODS

In this retrospective cohort study, one hundred five cases of ET of the infertility clinic of the Besat hospital (Kurdistan, Iran) between March 2014 to March 2020 that were treated with antagonist cycle (both fresh and frozen) were analyzed. The difference between the two groups in baseline data and reproductive outcomes were evaluated using Independent sample t test, Mann-Whitney U test, Chi-squared test, and Fisher's exact test in SPSS software (version 22).

RESULTS

Out of 105 cases, 48 and 57 were in the fresh and frozen ET groups, respectively. The participants age was 35.75 ± 4.9 Y. In the fresh ET group, and 33.98 ± 5.1 Y in the frozen ET group. The percentage of chemical pregnancy was 12 (25%) in the fresh ET group and 15 (26.3%) in the frozen ET group (P=0.8); Clinical pregnancy rate was 11 (22.9%) in the fresh ET group and 11 (19.3%) in the frozen ET group (P=0.6); the rate of abortion in the fresh ET group was 3 (6.3%, P=0.2), and in the frozen ET group was 8 (14%, P=0.2); and the live birth rate was 9 (18.8%) in the fresh ET group, in comparison with 7 (12.3%) in the frozen ET group (P=0.3).

CONCLUSION

Not statistically significant, the percentage of chemical pregnancy and abortion were higher in the frozen ET group. The percentage of clinical pregnancy and live birth were higher in the fresh ET group.

The effect of late-follicular phase progesterone elevation on embryo ploidy and cumulative live birth rates

RESEARCH QUESTION

Does late-follicular phase progesterone elevation have a deleterious effect on embryo euploidy, blastocyst formation rate and cumulative live birth rates (CLBR)?

DESIGN

A multicentre retrospective cross-sectional study including infertile patients aged 18-40 years who underwent ovarian stimulation in a gonadotrophin-releasing hormone antagonist protocol and preimplantation genetic testing for aneuploidies (PGT-A) followed by a freeze-all strategy and euploid embryo transfer between August 2017 and December 2019. The sample was stratified according to the progesterone concentrations on the day of trigger: normal (≤1.50 ng/ml) and high (>1.50 ng/ml). Moreover, sensitivity analyses were performed to determine whether different conclusions would have been drawn if different cut-offs had been adopted. The primary outcome was the embryo euploidy rate. Secondary outcomes were the blastocyst formation rate, the number of euploid blastocysts and CLBR.

RESULTS

Overall 1495 intracytoplasmic sperm injection PGT-A cycles were analysed. Late-follicular phase progesterone elevation was associated with significantly higher late-follicular oestradiol concentrations (2847.56 ± 1091.10 versus 2240.94 ± 996.37 pg/ml, P < 0.001) and significantly more oocytes retrieved (17.67 ± 8.86 versus 12.70 ± 7.00, P < 0.001). The number of euploid embryos was significantly higher in the progesterone elevation group (2.32 ± 1.74 versus 1.86 ± 1.42, P = 0.001), whereas the blastocyst formation rate (47.1% [43.7-50.5%] versus 51.0% [49.7-52.4%]), the embryo euploidy rate (48.3% [44.9-51.7%] versus 49.1% [47.7-50.6%], the live birth rate in the first frozen embryo transfer (34.1% versus 31.1%, P = 0.427) and CLBR (38.9% versus 37.0%, P = 0.637) were not significantly different between the two groups.

CONCLUSIONS

Euploidy rate and CLBR do not significantly differ among PGT-A cycles with and without late-follicular progesterone elevation in a freeze-all approach.

Elevated serum progesterone does not impact euploidy rates in PGT-A patients

PURPOSE

Some women undergoing stimulated cycles have elevated serum progesterone (P) on the day of ovulation trigger, but its effect on embryo quality is unclear. We analyze embryo quality among patients with high and low serum P undergoing preimplantation genetic testing for aneuploidy (PGT-A).

METHODS

This retrospective study included 1597 patients divided into two groups by serum P values: < 1.5 ng/mL or ≥ 1.5 ng/mL. A gonadotrophin-releasing hormone (GnRH) antagonist protocol was established for each patient. Serum P levels were measured on the day of triggering. Propensity score matching and Poisson regression were done. Age, body mass index, and ovarian sensitivity index were also compared.

RESULTS

Elevated serum P was not significantly associated with euploid embryo rate or other embryo-quality variables evaluated in our study. Age was the only variable associated with euploidy rate (per MII oocyte, P < 0.001; per biopsied embryo, P = 0.008), embryo biopsy rate (P < 0.001), absolute number of euploid embryos (P = 0.008), and top-quality embryo rate (P = 0.008). Categorical variables decreased in value for every year of increased age in patients with high serum P.

CONCLUSIONS

Elevated serum P did not affect the number of euploid and good-quality embryos for transfer in GnRH antagonist intracytoplasmic sperm injection (ICSI) cycles. Contrary to the clear influence of premature P elevation on endometrial receptivity based on literature, our results may help to tip the balance towards the absence of a negative effect of P elevation on embryo competence. More studies are needed to fully understand the effect of P elevation on reproductive outcomes.

Blastocyst Vitrification and Trophectoderm Biopsy Cumulatively Alter Embryonic Gene Expression in a Mouse Model

Although embryo vitrification has been used extensively in human assisted reproductive technology (ART) and animal models, epidemiologic evidence and randomized controlled trials suggest differences in pregnancy/perinatal outcomes (birthweight, risk for preterm birth, and pre-eclampsia) between babies born from fresh versus frozen embryo transfers. To address the uncertainty surrounding the effects of laboratory manipulations of embryos on clinical outcomes, we subjected mouse blastocysts to increasing levels of manipulation for transcriptome analysis. Blastocysts were randomly divided into four groups: no manipulation (control), single vitrification/thaw (1 vit), double vitrification/thaw (2 vit), and single vitrification/thaw plus trophectoderm biopsy and again vitrified/thawed (2 vit + bx). Three sets of 15 blastocysts in each group were pooled for RNA sequencing, and differentially expressed genes (DEGs) and pathways were determined by statistical analysis. Blastocysts were also stained for ZO-1 and F-actin to assess cytoskeletal integrity. Freeze/thaw and biopsy manipulation affected multiple biological pathways. The most significant differences were detected in genes related to innate immunity, apoptosis, and mitochondrial function, with the magnitude of change proportional to the extent to manipulation. Significant disruptions were also seen in cytoskeletal staining, with greater disruptions seen with greater of manipulation. Our data suggests that embryo vitrification and biopsy affect embryo gene transcription, with several identified DEGs that may have plausible mechanisms for the clinical outcomes seen in human offspring following ART. Further study is required to determine whether these alterations in gene expression are associated with clinical differences seen in children born from fresh or frozen embryo transfer.

Luteal Support with very Low Daily Dose of Human Chorionic Gonadotropin after Fresh Embryo Transfer as an Alternative to Cycle Segmentation for High Responders Patients Undergoing Gonadotropin-Releasing Hormone Agonist-Triggered IVF

The segmentation of the in vitro fertilization (IVF) cycle, consisting of the freezing of all embryos and the postponement of embryo transfer (ET), has become popular in recent years, with the main purpose of preventing ovarian hyperstimulation syndrome (OHSS) in patients with high response to controlled ovarian stimulation (COS). Indeed cycle segmentation (CS), especially when coupled to a GnRH-agonist trigger, was shown to reduce the incidence of OHSS in high-risk patients. However, CS increases the economic costs and the work amount for IVF laboratories. An alternative strategy is to perform a fresh ET in association with intensive luteal phase pharmacological support, able to overcome the negative effects of the GnRH-agonist trigger on the luteal phase and on endometrial receptivity. In order to compare these two strategies, we performed a retrospective, real-life cohort study including 240 non-polycystic ovarian syndrome (PCO) women with expected high responsiveness to COS (AMH >2.5 ng/mL), who received either fresh ET plus 100 IU daily human chorionic gonadotropin (hCG) as luteal support (FRESH group, n = 133), or cycle segmentation with freezing of all embryos and postponed ET (CS group, n = 107). The primary outcomes were: implantation rate (IR), live birth rate (LBR) after the first ET, and incidence of OHSS. Overall, significantly higher IR and LBR were observed in the CS group than in the FRESH group (42.9% vs. 27.8%, p < 0.05 and 32.7% vs. 19.5%, p < 0.05, respectively); the superiority of CS strategy was particularly evident when 16-19 oocytes were retrieved (LBR 42.2% vs. 9.5%, p = 0.01). Mild OHSS appeared with the same incidence in the two groups, whereas moderate and severe OHSS forms were observed only in the FRESH group (1.5% and 0.8%, respectively). In conclusion, in non-PCO women, high responders submitted to COS with the GnRH-antagonist protocol and GnRH-agonist trigger, CS strategy was associated with higher IR and LBR than the strategy including fresh ET followed by luteal phase support with a low daily hCG dose. CS appears to be advisable, especially when >15 oocytes are retrieved.

The clinical outcomes of fresh versus frozen embryos transfer in women ≥40 years with poor ovarian response

Objective

To compare the clinical outcomes of fresh embryo transfers (ETs) and frozen-thawed embryo transfers (FETs) after a freeze-all cycle in women ≥40 years old with poor ovarian response (POR).

Methods

We performed a single-center, retrospective, case-control study of patients who underwent in vitro fertilization between January 2014 and June 2019. We included a total of 192 patients aged 40 years or older from whom 3 or fewer oocytes had been retrieved and who were receiving cleavage-stage ET in this study. Of these patients, 101 and 91 patients underwent fresh ET and FET, respectively. The primary outcome was the live birth rate (LBR) after the first ET. Logistic regression analysis was used to compare the IVF outcomes and neonatal characteristics between the fresh ET and FET groups, adjusting for maternal age, body mass index, luteinizing hormone, and the number of good quality embryos transferred.

Results

The mean maternal ages and number of oocytes retrieved (43.2 years and 2.3 in both groups, P=0.902 and P=0.927, respectively) were similar in the fresh ET and FET groups. No significant difference was observed between the LBRs of the fresh ET and FET groups (adjusted odds ratio, 1.28; 95% confidence interval, 0.29–5.70). The clinical pregnancy and miscarriage rates, and neonatal characteristics (birth weights and premature infant rates) were similar between the 2 groups.

Conclusions

FET after the freeze-all strategy had no beneficial impact on the clinical outcomes of women ≥40 years with POR.

Perinatal and maternal outcomes after frozen versus fresh embryo transfer cycles in women of advanced maternal age

OBJECTIVE

The delay of childbearing in women has become a worldwide issue in recent decades. The application of assisted reproductive technology in women of advanced maternal age (AMA) is increasing. Evidence on the safety and outcomes of frozen embryo transfer (FET) compared with fresh embryo transfer (ET) in AMA women is still lacking. Therefore, the objective of the present study was to compare perinatal and maternal outcomes after autologous FET and fresh ET cycles in women of AMA.

STUDY DESIGN

A retrospective study of 1663 FET and 3964 fresh ET cycles in reproductive medical centers from 2009 to 2014. Women who aged ≥35 years and had clinical pregnancies after autologous frozen or fresh ET were included. The main perinatal outcomes included birth weight, gestational age, rates of preterm birth, macrosomia, low birth weight (LBW), and very low birth weight. The main maternal outcomes included rates of hypertensive disorders of pregnancy, gestational diabetes mellitus, and preterm premature rupture of the membranes.

RESULTS

Women who underwent FET had an increased risk of hypertensive disorders of pregnancy [1.1 % vs. 0.4 %, adjusted OR (95 % CI): 2.76 (1.39-5.51); p = 0.004]. Singletons born after FET had significantly higher mean birth weight (3388.78 ± 538.47 vs. 3316.19 ± 549.08; p = 0.001). Furthermore, increased risk of macrosomia [13.5 % vs. 10.4 %, adjusted OR (95 % CI): 1.35 (1.07-1.71); p = 0.013] and decreased risk of LBW [3.6 % vs. 5.3 %, adjusted OR (95 % CI): 0.67 (0.45-1.00); p = 0.048] were found in singletons born after FET.

CONCLUSIONS

Perinatal risks of AMA patients are higher in FET than in fresh ET, including higher birth weight, risks of macrosomia in singleton births, and hypertensive disorders of pregnancy.

Association of the duration of post-thaw culture with clinical outcome after vitrified-warmed day 3 embryo transfer in 10,464 cycles: A retrospective cohort study

This study aimed to investigate the effect of the duration of embryo culture on clinical outcome in vitrified-warmed cycles.This retrospective cohort study enrolled 10,464 infertile patients, with a total of 18,843 vitrified-warmed day 3 embryos from 2012 to 2017 at a single center. The patients were divided into 2 groups: 9470 cycles in the short-term culture group (0.5-8 hours of post-thaw culture) and 994 cycles in the 48 to 72 hours culture group. The independent effect of the following variables on clinical outcomes was determined: duration of post-thaw culture, maternal age, transferred embryos, embryo quality, and endometrial thickness.We found that the pregnancy rate was positively associated with the post-thaw culture time. Ordinary least square regression analyses showed that the duration of post-thaw culture was positively associated with implantation and live birth rates overall. However, the implantation and live birth rates were not significantly associated with the post-thaw culture time in the short-term culture group. Additionally, maternal age and the number of transferred embryos were independent predictors of the implantation and live birth rates. Moreover, the duration of post-thaw culture did not affect live birth weight.These results indicated that the pregnancy rate is positively associated with the duration of post-thaw culture. Therefore, under the condition of not affecting work shifts, properly prolonging the duration of post-thaw culture to improve the outcome of frozen-thawed embryo transfer should be considered.

Controlled ovarian stimulation and progesterone supplementation affect vaginal and endometrial microbiota in IVF cycles: a pilot study

Purpose

Does controlled ovarian stimulation (COS) and progesterone (P) luteal supplementation modify the vaginal and endometrial microbiota of women undergoing in vitro fertilization?

Methods

Fifteen women underwent microbiota analysis at two time points: during a mock transfer performed in the luteal phase of the cycle preceding COS, and at the time of fresh embryo transfer (ET). A vaginal swab and the distal extremity of the ET catheter tip were analyzed using next-generation 16SrRNA gene sequencing. Heterogeneity of the bacterial microbiota was assessed according to both the Bray-Curtis similarity index and the Shannon diversity index.

Results

Lactobacillus was the most prevalent genus in the vaginal samples, although its relative proportion was reduced by COS plus P supplementation (71.5 ± 40.6% vs. 61.1 ± 44.2%). In the vagina, an increase in pathogenic species was observed, involving Prevotella (3.5 ± 8.9% vs. 12.0 ± 19.4%), and Escherichia coli-Shigella spp. (1.4 ± 5.6% vs. 2.0 ± 7.8%). In the endometrium, the proportion of Lactobacilli slightly decreased (27.4 ± 34.5% vs. 25.0 ± 29.9%); differently, both Prevotella and Atopobium increased (3.4 ± 9.5% vs. 4.7 ± 7.4% and 0.7 ± 1.5% vs. 5.8 ± 12.0%). In both sites, biodiversity was greater after COS (p < 0.05), particularly in the endometrial microbiota, as confirmed by Bray-Curtis analysis of the phylogenetic distance among bacteria genera. Bray-Curtis analysis confirmed significant differences also for the paired endometrium-vagina samples at each time point.

Conclusions

Our findings suggest that COS and P supplementation significantly change the composition of vaginal and endometrial microbiota. The greater instability could affect both endometrial receptivity and placentation. If our findings are confirmed, they may provide a further reason to encourage the freeze-all strategy.

Impact of elective frozen vs. fresh embryo transfer strategies on cumulative live birth: Do deleterious effects still exist in normal & hyper responders?

Background

Is freeze-all strategy effective in terms of cumulative live birth rates (CLBRs) in all patients?

Methods

This retrospective single-center study analyzed the CLBRs of 2523 patients undergoing fresh or electively frozen blastocyst transfer cycles. In 1047, cycles, the fresh embryo transfer (ET) strategy was applied for the 1^st ET, whereas electively frozen ET (e-FET) was performed in 1476 cycles. Female age ≤ 37 and blastocysts frozen via vitrification were included. The patients in each arm were further stratified into four subgroups according to the number of oocytes retrieved as follows: Group A: 1–5, group B: 6–10, group C: 11–15 and group D: 16–25 oocytes retrieved. The primary endpoint was the CLBR. The secondary endpoints were the ovarian hyperstimulation syndrome (OHSS) rate and the live birth rates (LBRs) following fresh ETs and e-FETs for the first transfers.

Result(s)

The CLBR was similar between the fresh ET and e-FET arms in group A (35/76 (46.1%) vs 29/67 (43.3%), p = 0.74) and group B (165/275 (60%) vs 216/324 (66.7%), p = 0.091), whereas significantly higher rates were detected in favor of the e-FET arm within group C (328/460 (71.3%) vs 201/348 (57.8%), p<0.001) and group D (227/348 (65.2%), vs 446/625 (71.5%), p<0.001). The OHSS rate was also found to be higher in the fresh ET arm among group C (12/348 (3.4%) vs 0/460 (0%), p<0.001) and group D (38/348 (10.9%) vs 3/625 (0.5%), p<0.001) patients than e-FET arm. Perinatal and obstetrical outcomes were nonsignificantly different between fresh and e-FET arms. However, the birth weights were significantly lower for fresh ET, 3064 versus 3201 g for singletons (p<0.001)

Conclusion

Compared with a fresh-transfer strategy, the e-FET strategy resulted in a higher CLBR among patients with >10 oocytes retrieved during stimulated cycles.

Fertility preservation in breast cancer with case-based examples for guidance

With more young breast cancer survivors, a trend toward having children later in life, and improvements in assisted reproductive technology (ART), fertility preserving techniques are of growing importance prior to initiation of gonadotoxic treatments. The American Society for Clinical Oncology (ASCO) updated their Fertility Preservation in Patients with Cancer guidelines in April of 2018. ASCO continues to recognize oocyte and embryo cryopreservation as standard practice for women interested in preserving fertility and sperm cryopreservation as standard practice for men. ASCO has clarified their statement on ovarian suppression during chemotherapy as an option when standard methods are unavailable but should not be used as the sole method of fertility preservation (FP) due to conflicting evidence. ASCO also updated their statement on ovarian tissue cryopreservation, which is still labeled experimental but ASCO acknowledges that it can restore global ovarian function and could be of use in specific patients. The NCCN's Version 1.2018 Clinical Practice Guidelines® for treatment of breast cancer include fertility counseling as part of their work-up in all types of breast cancer for premenopausal women.The purpose of this review is to explain the indications and evidence for the different methods of FP for young breast cancer patients in accordance with ASCO and NCCN guidelines. The guidance will then be applied to three theoretical clinical cases in order to highlight actual use in clinical practice.

Clinical factors that affect the pregnancy rate in frozen-thawed embryo transfer in the freeze-all policy

Background

This study was conducted to analyze clinical factors that can affect pregnancy rates in normal responders undergoing the freeze-all policy in in vitro fertilization.

Methods

We evaluated 153 embryo transfer cycles in 89 infertile women with normal response to controlled ovarian stimulation (COS). After COS, all embryos were cultured to the blastocyst stage, and good quality blastocysts were vitrified for elective frozen-thawed embryo transfer (FET). Clinical variables associated with COS and the results of COS and culture, including the number of retrieved oocytes, fertilized oocytes, and frozen blastocysts were compared between the pregnant group and the non-pregnant group.

Results

After a single cycle of COS for each patient, 52 patients became pregnant while 37 did not. Significant differences were observed in the number of matured oocytes, fertilized oocytes, frozen blastocysts, and transferred embryos. The number of frozen blastocysts in the pregnant group was almost twice that in the non-pregnant group (5.6±3.1 vs. 2.8±1.9, p<0.001). The area under the receiver operating characteristic curve for the 4 frozen blastocysts was 0.801 in the pregnant group.

Conclusion

In the freeze-all policy, the number of matured oocytes, number of fertilized oocytes, and number of frozen blastocysts might be predictive factors for pregnancy.

GnRH antagonist versus follicular-phase single-dose GnRH agonist protocol in patients of normal ovarian responses during controlled ovarian stimulation

OBJECTIVE

This study aims to explore the differences of the ovarian stimulation (OS) characteristics, laboratory, and clinical outcomes between follicular-phase single-dose gonadotropin-releasing hormone (GnRH) agonist protocol and GnRH antagonist protocol during controlled ovarian hyperstimulation (COH).

METHODS

About 1883 consecutive IVF/ICSI fresh cycles of normal ovarian responders were retrospectively analyzed, with 1229 in the single-dose GnRH agonist protocol group and 654 in the GnRH antagonist protocol group at Reproductive Medical Center of Tongji Hospital from 1 January 2014 to 31 December 2017.

RESULTS

The follicular-phase single-dose GnRH agonist group showed significantly more oocytes obtained, higher implantation rate and pregnancy rate, as well as lower luteinizing hormone (LH) level and estradiol (E2)/oocyte ratio on the day of human chorionic gonadotropin (hCG) administration. However, differences were not significant in meiosis II (MII) oocyte rate, two pronuclear zygote (2PN) embryo rate, viable embryo rate or high-quality embryo rate, compared with the GnRH antagonist group. Further comparison of clinical outcomes in the first frozen-thawed cycles did not show significant difference in either implantation or clinical pregnancy rate between the two protocol groups.

CONCLUSIONS

Follicular-phase single-dose GnRH agonist protocol may achieve better clinical outcomes in normal ovarian responders, which could be explained more by positive effect on endometrial receptivity rather than embryo quality.

Cumulative live birth rates following a 'freeze-all' strategy: a population-based study

STUDY QUESTION

What is the cumulative live birth rate following a 'freeze-all' strategy compared with a 'fresh-transfer' strategy?

SUMMARY ANSWER

The 'freeze-all' strategy resulted in a similar cumulative live birth rate as the 'fresh-transfer' strategy among high responders (>15 oocytes retrieved) but did not benefit normal (10-15 oocytes) and suboptimal responders (<10 oocytes).

WHAT IS KNOWN ALREADY

Frozen-thawed embryo transfer is associated with a decreased risk of adverse obstetric and perinatal outcomes compared with fresh embryo transfer. It is unclear whether the 'freeze-all' strategy should be offered to all women undergoing ART treatment.

STUDY DESIGN SIZE DURATION

A population-based retrospective cohort study using data collected by the Victorian Assisted Reproductive Treatment Authority. This study included 14 331 women undergoing their first stimulated ART cycle with at least one oocyte fertilised between 1 July 2009 and 30 June 2014 in Victoria, Australia. Demographic characteristics, type of ART procedures and resulting pregnancy and birth outcomes were recorded for the stimulated cycle and associated thaw cycles until 30 June 2016, or until a live birth was achieved, or until all embryos from the stimulated cycle had been used.

PARTICIPANTS/MATERIALS SETTING METHODS

Women were grouped by whether they had undergone the 'freeze-all' strategy (n = 1028) where all embryos were cryopreserved for future transfer, or the 'fresh-transfer' strategy (n = 13 303) where selected embryo(s) were transferred in the stimulated cycle, and remaining embryo(s) were cryopreserved for future use. A discrete-time survival model was used to evaluate the cumulative live birth rate following 'freeze-all' and 'fresh-transfer' strategy.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 1028 women undergoing 'freeze-all' strategy and 13 303 women undergoing 'fresh-transfer' strategy had 1788 and 22 334 embryo transfer cycles resulting in 452 and 5126 live births, respectively. Most women (61.3%) in the 'freeze-all' group had more than 15 oocytes retrieved in the stimulated cycle compared with 18.1% of women in the 'fresh-transfer' group (P < 0.001). For high responders (>15 oocytes), the cumulative live birth rate in the 'freeze-all' group was similar to the 'fresh-transfer' group (56.8% vs. 56.2%, adjusted hazard ratio (AHR) 0.90, 95% CI 0.77-1.04). However, the likelihood of a live birth was lower in the 'freeze-all' group compared with the 'fresh-transfer' group among normal responders (10-15 oocytes) (33.2% vs. 46.3%, AHR 0.62, 95% CI 0.46-0.83) and suboptimal responders (<10 oocytes) (14.6% vs. 28.0%, AHR 0.67, 95% CI 0.14-1.01). During the minimum follow-up time of 2 years, 34.1%, 24.4% and 8.4% of suboptimal, normal and high responders, respectively, in the 'freeze-all' group did not return for any embryo transfer after the stimulated cycle, whereas all women in the 'fresh-transfer' group had at least one embryo transferred in the stimulated cycle.

LIMITATIONS REASONS FOR CAUTION

A limitation of this population-based study is the lack of information available on clinic-specific protocols for the 'freeze-all' strategy and the potential impact of these on outcomes. Data were not available on whether the 'freeze-all' strategy was used to prevent ovarian hyperstimulation syndrome (OHSS).

WIDER IMPLICATIONS OF THE FINDINGS

This study presents population-based evidence on clinical efficacy associated with a 'freeze-all' and 'fresh-transfer' strategy. The 'freeze-all' strategy may benefit some subgroups of patients, including women who are high responders and those who are at risk of OHSS, but should not be offered universally. Clinicians should consider the potential impact of electively deferring embryo transfer on treatment discontinuation in choosing the optimal embryo transfer strategy for couples undergoing ART treatment.

STUDY FUNDING/COMPETING INTERESTS

No specific funding was received to undertake this study. There is no conflict of interest, except that M.B. is a shareholder in Genea Ltd.

Cumulative live birth rate in freeze-all cycles is comparable to that of a conventional embryo transfer policy at the cleavage stage but superior at the blastocyst stage

OBJECTIVE

To determine whether the freeze-all policy ensures a higher efficacy in terms of cumulative live birth rate (CLBR) in comparison with a conventional fresh/frozen embryo transfer (ET) approach in patients with normal ovarian response.

DESIGN

Retrospective, matched, multicenter cohort study.

SETTING

Private IVF centers.

PATIENT(S)

This study analyzed 564 completed IVF cycles in which an average of 12-18 oocytes were retrieved. In 435 cycles the conventional strategy was applied, with initial ET followed by frozen embryo replacements, whereas in 129 cycles the freeze-all policy was performed, with elective cryopreservation and deferred use of all viable embryos.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The primary endpoint was CLBR. The secondary endpoint was cumulative clinical pregnancy rate.

RESULT(S)

Overall, statistically comparable CLBRs were achieved in the fresh/frozen and freeze-all groups (45.5% vs. 53.5%). Stratification of data for age and number of retrieved oocytes confirmed the absence of differences between the two groups. In a subanalysis in which the day of ET and cryopreservation were taken into account, a similar outcome was achieved in cleavage-stage groups (45.6% vs. 46.4%), whereas when ET was performed at the blastocyst stage the CLBR was significantly higher in the freeze-all group (45.3% vs. 66.7%).

CONCLUSION(S)

Our CLBR analysis indicates that clinical performance of the freeze-all policy is equivalent to that of the conventional strategy when ET is carried out at the cleavage stage. However, it seems to be superior if associated with cryopreservation and transfer at the blastocyst stage.

Fertility and Neonatal Outcomes of Freeze-All vs. Fresh Embryo Transfer in Women With Advanced Endometriosis

Background: Eutopic endometrium from women with endometriosis has functional changes in several aspects, which may largely account for the decrease in the quality of endometrial receptivity. It is of utmost importance to know whether freeze-all strategy can restore optimal receptivity in endometriotic women leading to the better ART outcomes. Methods: Retrospective study involved patients with advanced endometriosis undergoing first embryo transfer cycles during the period from March 2006 to March 2017 at a tertiary care center. After propensity score matching, there were 506 women in the freeze-all group and 255 women in fresh group. Our main outcomes included the rates of implantation, clinical pregnancy, and live birth. Subgroup analyses were performed after stratification by the number of oocytes retrieved and fertilization method. Neonatal outcomes included gestational age and birth weight z-score for singletons and multiple births. Results: In our matched cohort, the implantation, clinical pregnancy and live birth rates were statistically significantly higher in the freeze-all group compared with fresh transfer groups (34.4 vs. 25.5%, 51.8 vs. 38.8%, and 45.3 vs. 31.8%, all P < 0.001, respectively). A more beneficial effect of freeze-all cycles was found in patients who got more than 15 oocytes. Additionally, when ICSI insemination techniques were used to achieve fertilization, the advantage of freeze-all strategy was not obvious. Assessment of 382 babies showed no statistically significant difference in the mode of delivery, sex of live-born, gestational age, unadjusted median birth weight, and z-score between two study groups. Conclusion: Freeze-all strategy is an attractive option to improve the outcomes of ART for women with advanced endometriosis.

Lipidomic profile as a noninvasive tool to predict endometrial receptivity

For the present study we asked whether the endometrial fluid lipidomic may be a useful approach to predict endometrial receptivity in freeze-all cycles. For this case-control study, endometrial fluid samples were collected from 41 patients undergoing freeze-all cycles. Samples were split depending on the pregnancy outcome: positive group (n = 24) and negative group (n = 17). Data were acquired by the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were applied. A list of potential biomarker ion ratios was obtained and the values were used to build a receiver operating characteristic (ROC) curve to predict pregnancy success. The lipid categories were attributed by LIPID MAPS database. Ion ratios were established according to their correlations and used for the analysis. The PCA showed a tendency of separation between the studied groups, whereas the PLS-DA was able to clearly distinguish them. Fifteen ratios (13 hyper-represented in the negative and two hyper-represented in the positive group) were selected according to their importance for model prediction. These ratios were used to build the ROC curve, which presented an area under curve of 84.0% (95%CI: 69.2-97.4%; p = 0.009). These findings suggest that lipidomic profiling of endometrial fluid may be a valuable tool for identifying the time interval comprising the window of implantation.

Does freeze-all policy affect IVF outcome in poor ovarian responders?

OBJECTIVE

To evaluate whether the freeze-all strategy affects in-vitro fertilization (IVF) outcome in poor ovarian responders (POR) defined according to the Bologna criteria.

METHOD

This was a retrospective cohort study of patients undergoing IVF treatment between January 2012 and December 2016 at a single center. A total of 433 POR (as defined by the Bologna criteria) fulfilled criteria and were included in the study; of these, 277 patients underwent fresh embryo transfer (ET) and 156 followed the freeze-all policy. All patients underwent controlled ovarian stimulation (COS) following a gonadotropin-releasing hormone antagonist protocol, and cleavage-stage ET. Main outcome measure was ongoing pregnancy rate. Secondary outcomes included implantation and clinical pregnancy rates. The freeze-all strategy was implemented when the progesterone serum level was > 1.5 ng/mL or the endometrium was < 7 mm on the trigger day, or as per patient preference. Patients with previous failed fresh ET also underwent fresh ET or freeze-all strategy considering the indications mentioned above.

RESULTS

Mean maternal age in the freeze-all group was 39.5 ± 3.6 years and in the fresh ET group was 39.7 ± 3.8 years (P = 0.54). Mean number of embryos transferred (nET) was 1.53 ± 0.6 and 1.60 ± 0.6 (P = 0.12) in the freeze-all and fresh ET groups, respectively. Ongoing pregnancy rate did not differ significantly between the freeze-all and fresh ET groups (9.6% vs 10.1%, respectively; relative risk (RR), 0.95; 95% CI, 0.52-1.73), nor did the clinical pregnancy rate (14.1% vs 13.7%, respectively; RR, 1.03; 95% CI, 0.63-1.67). Implantation rate was 9.6% and 9.8% (P = 0.82) in the freeze-all and fresh ET groups, respectively. Logistic regression analysis (including maternal age, antral follicle count, number of retrieved and mature oocytes, nET, and fresh ET vs freeze-all strategy) indicated that maternal age (P < 0.001) and nET (P = 0.039) were the only independent variables associated with ongoing pregnancy rate.

CONCLUSIONS

The freeze-all strategy, compared with fresh ET, had no impact on IVF outcomes in POR patients as defined according to the Bologna criteria. Multicenter studies including large numbers of patients should be carried out to confirm the results of this study and reach conclusions about the potential benefits of the freeze-all policy for poor responders. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Freezing of all embryos in in vitro fertilization is beneficial in high responders, but not intermediate and low responders: an analysis of 82,935 cycles from the Society for Assisted Reproductive Technology registry

OBJECTIVE

To assess in vitro fertilization (IVF) and pregnancy outcomes in patients having their first frozen embryo transfer (FET) after a freeze-all cycle versus similar patients having their first fresh embryo transfer (ET).

DESIGN

Retrospective cohort study.

SETTING

None.

PATIENT(S)

Registry data on 82,935 patient cycles from the Society for Assisted Reproductive Technology (SART).

INTERVENTION(S)

All first fresh autologous IVF cycles were analyzed and compared to first FET cycles after a freeze-all first IVF stimulation. The cycles were subdivided into cohorts based upon the number of oocytes retrieved (OR): 1-5 (low), 6-14 (intermediate), and 15+ (high responders). Univariate analyses were performed on cycle characteristics, and multivariable regression analyses were performed on outcome data.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy rate (CPR) and live-birth rate (LBR).

RESULTS

Of the 82,935 cycles analyzed, 69,102 patients had their first fresh transfer, and 13,833 had a first FET. High responders were found to have a higher CPR and LBR in the FET cycles compared with the fresh ET cycles (61.5 vs. 57.4%; 52.0 vs. 48.9%). In intermediate responders, both CPR and LBR were higher after fresh ET compared with FET (49.6% vs. 44.2%; 41.2 vs. 35.3%). Similarly, in low responders, CPR and LBR were higher after fresh compared with FET (33.2% vs. 15.9%; 25.9% vs. 11.5%).

CONCLUSION(S)

A freeze-all strategy is beneficial in high responders but not in intermediate or low responders, thus refuting the idea that freeze-all cycles are preferable for all patients.

The Effect of Supraphysiological Estradiol on Pregnancy Outcomes Differs Between Women With PCOS and Ovulatory Women

CONTEXT

Supraphysiological estradiol exposure after ovarian stimulation may disrupt embryo implantation after fresh embryo transfer. Women with polycystic ovary syndrome (PCOS), who usually overrespond to ovarian stimulation, have a better live birth rate after frozen embryo transfer (FET) than after fresh embryo transfer; however, ovulatory women do not.

OBJECTIVE

To evaluate whether the discrepancy in live birth rate after fresh embryo transfer vs FET between these two populations is due to the variation in ovarian response (i.e., peak estradiol level or oocyte number).

DESIGN, SETTING, PATIENTS, INTERVENTION(S), AND MAIN OUTCOME MEASURE(S)

This was a secondary analysis of data from two multicenter randomized trials with similar study designs. A total of 1508 women with PCOS and 2157 ovulatory women were randomly assigned to undergo fresh or FET. The primary outcome was live birth.

RESULTS

Compared with fresh embryo transfer, FET resulted in a higher live birth rate (51.9% vs 40.7%; OR, 1.57; 95% CI, 1.22 to 2.03) in PCOS women with peak estradiol level >3000pg/mL but not in those with estradiol level ≤3000 pg/mL. In women with PCOS who have ≥16 oocytes, FET yielded a higher live birth rate (54.8% vs 42.1%; OR, 1.67; 95% CI, 1.20 to 2.31), but this was not seen in those with <16 oocytes. In ovulatory women, pregnancy outcomes were similar after fresh embryo transfer and FET in all subgroups.

CONCLUSIONS

Supraphysiological estradiol after ovarian stimulation may adversely affect pregnancy outcomes in women with PCOS but not in ovulatory women.

Transfer of Fresh versus Frozen Embryos in Ovulatory Women

BACKGROUND

Elective frozen-embryo transfer has been shown to result in a higher live-birth rate than fresh-embryo transfer among anovulatory women with the polycystic ovary syndrome. It is uncertain whether frozen-embryo transfer increases live-birth rates among ovulatory women with infertility.

METHODS

In this multicenter, randomized trial, we randomly assigned 2157 women who were undergoing their first in vitro fertilization cycle to undergo either fresh-embryo transfer or embryo cryopreservation followed by frozen-embryo transfer. Up to two cleavage-stage embryos were transferred in each participant. The primary outcome was a live birth after the first embryo transfer.

RESULTS

The live-birth rate did not differ significantly between the frozen-embryo group and the fresh-embryo group (48.7% and 50.2%, respectively; relative risk, 0.97; 95% confidence interval [CI], 0.89 to 1.06; P=0.50). There were also no significant between-group differences in the rates of implantation, clinical pregnancy, overall pregnancy loss, and ongoing pregnancy. Frozen-embryo transfer resulted in a significantly lower risk of the ovarian hyperstimulation syndrome than fresh-embryo transfer (0.6% vs. 2.0%; relative risk, 0.32; 95% CI, 0.14 to 0.74; P=0.005). The risks of obstetrical and neonatal complications and other adverse outcomes did not differ significantly between the two groups.

CONCLUSIONS

The live-birth rate did not differ significantly between fresh-embryo transfer and frozen-embryo transfer among ovulatory women with infertility, but frozen-embryo transfer resulted in a lower risk of the ovarian hyperstimulation syndrome. (Funded by the National Key Research and Development Program of China and the National Natural Science Foundation of China; Chinese Clinical Trial Registry number, ChiCTR-IOR-14005406 .).

A universal freeze all strategy: why it is not warranted

PURPOSE OF REVIEW

There's some preclinical evidence of an adverse effect of multifollicular growth on endometrial function in assisted reproductive technology cycles. Universal elective frozen embryo transfer (eFET) in an unstimulated cycle is being promoted as a panacea, regardless of patient, and cycle characteristics. We review the clinical evidence on the effectiveness and safety of eFETs.

RECENT FINDINGS

Randomized controlled trials (RCTs) comparing fresh and eFET yield contradictory results in terms of live birth rates. RCTs mainly involve women with an excessive response to ovarian stimulation. Studies including women with a normal or low ovarian response are either patient/physician preference or retrospective studies, prone to bias. Yet, they yield contradictory results as well. Overall, eFET seems to have limited potential to improve effectiveness of assisted reproductive technology, which could be limited to hyper-responders. Other suggested advantages of eFET include better obstetric and perinatal outcome. However, recent studies show that frozen embryo transfers can be associated with serious complications including hypertensive disorders during pregnancy, placenta accreta, or increased perinatal mortality.

SUMMARY

The evidence behind advantages of eFET is of low quality. As such, switching to a universal eFET strategy does not seem justified. New RCTs including women from different strata of ovarian response are needed.