Birth after transfer of frozen-thawed vitrified biopsied blastocysts

Ovarian response and embryo ploidy following oral micronized progesterone-primed ovarian stimulation versus GnRH antagonist protocol. A prospective study with repeated ovarian stimulation cycles

STUDY QUESTION

Is there any difference in ovarian response and embryo ploidy following progesterone-primed ovarian stimulation (PPOS) using micronized progesterone or GnRH antagonist protocol?

SUMMARY ANSWER

Pituitary downregulation with micronized progesterone as PPOS results in higher number of oocytes retrieved and a comparable number of euploid blastocysts to a GnRH antagonist protocol.

WHAT IS KNOWN ALREADY

Although the GnRH antagonist is considered by most the gold standard protocol for controlling the LH surge during ovarian stimulation (OS) for IVF/ICSI, PPOS protocols are being increasingly used in freeze-all protocols. Still, despite the promising results of PPOS protocols, an early randomized trial reported potentially lower live births in recipients of oocytes resulting following downregulation with medroxyprogesterone acetate as compared with a GnRH antagonist protocol. The scope of the current prospective study was to investigate whether PPOS with micronized progesterone results in an equivalent yield of euploid blastocysts to a GnRH antagonist protocol.

STUDY DESIGN, SIZE, DURATION

In this prospective study, performed between September 2019 to January 2022, 44 women underwent two consecutive OS protocols within a period of 6 months in a GnRH antagonist protocol or in a PPOS protocol with oral micronized progesterone.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Overall, 44 women underwent two OS cycles with an identical fixed dose of rFSH (225 or 300 IU) in both cycles. Downregulation in the first cycles was performed with the use of a flexible GnRH antagonist protocol (0.25 mg per day as soon as one follicle of 14 mm) and consecutively, after a washout period of 1 month, control of LH surge was performed with 200 mg of oral micronized progesterone from stimulation Day 1. After the completion of both cycles, all generated blastocysts underwent genetic analysis for aneuploidy screening (preimplantation genetic testing for aneuplody, PGT-A).

MAIN RESULTS AND THE ROLE OF CHANCE

Comparisons between protocols did not reveal differences between the duration of OS. The hormonal profile on the day of trigger revealed statistically significant differences between protocols in all the tested hormones except for FSH: with significantly higher serum E2 levels, more elevated LH levels and higher progesterone levels in PPOS cycles as compared with antagonist cycles, respectively. Compared with the GnRH antagonist protocol, the PPOS protocol resulted in a significantly higher number of oocytes (12.7 ± 8.09 versus 10.3 ± 5.84; difference between means [DBM] -2.4 [95% CI -4.1 to -0.73]), metaphase II (9.1 ± 6.12 versus 7.3 ± 4.15; DBM -1.8 [95% CI -3.1 to -0.43]), and 2 pronuclei (7.1 ± 4.99 versus 5.7 ± 3.35; DBM -1.5 [95% CI -2.6.1 to -0.32]), respectively. Nevertheless, no differences were observed regarding the mean number of blastocysts between the PPOS and GnRH antagonist protocols (2.9 ± 2.11 versus 2.8 ± 2.12; DBM -0.07 [95% CI -0.67 to 0.53]) and the mean number of biopsied blastocysts (2.9 ± 2.16 versus 2.9 ± 2.15; DBM -0.07 [95% CI -0.70 to 0.56]), respectively. Concerning the euploidy rates per biopsied embryo, a 29% [95% CI 21.8-38.1%] and a 35% [95% CI 26.6-43.9%] were noticed in the PPOS and antagonist groups, respectively. Finally, no difference was observed for the primary outcome, with a mean number of euploid embryos of 0.86 ± 0.90 versus 1.00 ± 1.12 for the comparison of PPOS versus GnRh antagonist.

LIMITATIONS, REASONS FOR CAUTION

The study was powered to detect differences in the mean number of euploid embryos and not in terms of pregnancy outcomes. Additionally, per protocol, there was no randomization, the first cycle was always a GnRH antagonist cycle and the second a PPOS with 1 month of washout period in between.

WIDER IMPLICATIONS OF THE FINDINGS

In case of a freeze-all protocol, clinicians may safely consider oral micronized progesterone to control the LH surge and patients could benefit from the advantages of a medication of oral administration, with a potentially higher number of oocytes retrieved at a lower cost, without any compromise in embryo ploidy rates.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by an unrestricted grant from Theramex. N.P.P. has received Research grants from Merck Serono, Organon, Ferring Pharmaceutical, Roche, Theramex, IBSA, Gedeon Richter, and Besins Healthcare; honoraria for lectures from: Merck Serono, Organon, Ferring Pharmaceuticals, Besins International, Roche Diagnostics, IBSA, Theramex, and Gedeon Richter; consulting fees from Merck Serono, Organon, Besins Healthcare, and IBSA. M.d.M.V., F.M., and I.R. declared no conflicts of interest.

TRIAL REGISTRATION NUMBER

The study was registered at Clinical Trials Gov. (NCT04108039).

Blastocysts from partial compaction morulae are not defined by their early mistakes

RESEARCH QUESTION

Is partial compaction during morula formation associated with an embryo's developmental ability and implantation potential?

DESIGN

Retrospective analysis of data from 196 preimplantation genetic testing for aneuploidy (PGT-A) cycles. Embryos starting compaction were grouped according to the inclusion or not of all the blastomeres in the forming morula (full compaction or partial compaction). The possible effect of maternal age and ovarian response on compaction was analysed. Morphokinetic characteristics, blastocyst formation rate, morphology and cytogenetic constitution of the obtained blastocysts were compared. Comparisons of reproductive outcomes after the transfer of euploid blastocysts from both groups were established. Finally, in a subset of embryos, the chromosomal constitution concordance of the abandoned cells and the corresponding blastocyst through trophectoderm biopsies was assessed.

RESULTS

A total of 430 embryos failed to include at least one cell during compaction (partial compaction group [49.3%]), whereas the 442 remaining embryos formed a fully compacted morula (full compaction group [50.7%]). Neither female age nor the number of oocytes collected affected the prevalence of partial compaction morulae. Morphokinetic parameters were altered in embryos from partial compaction morulae compared with full compaction. Although an impairment in blastocyst formation rate was observed in partial compaction morulae (57.2% versus 70.8%, P < 0.001), both chromosomal constitution (euploidy rate: partial compaction [38.4%] versus full compaction [34.2%]) and reproductive outcomes (live birth rate: partial compaction [51.9%] versus full compaction [46.2%]) of the obtained blastocysts were equivalent between groups. A high ploidy correlation of excluded cells-trophectoderm duos was observed.

CONCLUSIONS

Partial compaction morulae show a reduced developmental ability compared with full compaction morulae. Resulting blastocysts from both groups, however, have similar euploidy rates and reproductive outcomes. Cell exclusion might be a consequence of a compromised embryo development regardless of the chromosomal constitution of the excluded cells.

Individualised luteal phase support in artificially prepared frozen embryo transfer cycles based on serum progesterone levels: a prospective cohort study

STUDY QUESTION

Does an individualised luteal phase support (iLPS), according to serum progesterone (P4) level the day prior to euploid frozen embryo transfer (FET), improve pregnancy outcomes when started on the day previous to embryo transfer?

SUMMARY ANSWER

Patients with low serum P4 the day prior to euploid FET can benefit from the addition of daily subcutaneous P4 injections (Psc), when started the day prior to FET, and achieve similar reproductive outcomes compared to those with initial adequate P4 levels.

WHAT IS KNOWN ALREADY

The ratio between FET/IVF has spectacularly increased in the last years mainly thanks to the pursuit of an ovarian hyperstimulation syndrome free clinic and the development of preimplantation genetic testing (PGT). There is currently a big concern regarding the endometrial preparation for FET, especially in relation to serum P4 levels around the time of embryo transfer. Several studies have described impaired pregnancy outcomes in those patients with low P4 levels around the time of FET, considering 10 ng/ml as one of the most accepted reference values. To date, no prospective study has been designed to compare the reproductive outcomes between patients with adequate P4 the day previous to euploid FET and those with low, but restored P4 levels on the transfer day after iLPS through daily Psc started on the day previous to FET.

STUDY DESIGN, SIZE, DURATION

A prospective observational study was conducted at a university-affiliated fertility centre between November 2018 and January 2020 in patients undergoing PGT for aneuploidies (PGT-A) IVF cycles and a subsequent FET under hormone replacement treatment (HRT). A total of 574 cycles (453 patients) were analysed: 348 cycles (leading to 342 euploid FET) with adequate P4 on the day previous to FET, and 226 cycles (leading to 220 euploid FET) under iLPS after low P4 on the previous day to FET, but restored P4 levels on the transfer day.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Overall we included 574 HRT FET cycles (453 patients). Standard HRT was used for endometrial preparation. P4 levels were measured the day previous to euploid FET. P4 > 10.6 ng/ml was considered as adequate and euploid FET was performed on the following day (FET Group 1). P4 < 10.6 ng/ml was considered as low, iLPS was added in the form of daily Psc injections, and a new P4 analysis was performed on the following day. FET was only performed on the same day when a restored P4 > 10.6 ng/ml was achieved (98.2% of cases) (FET Group 2).

MAIN RESULTS AND THE ROLE OF CHANCE

Patient's demographics and cycle parameters were comparable between both euploid FET groups (FET Group 1 and FET Group 2) in terms of age, weight, oestradiol and P4 levels and number of embryos transferred. No statistically significant differences were found in terms of clinical pregnancy rate (56.4% vs 59.1%: rate difference (RD) -2.7%, 95% CI [-11.4; 6.0]), ongoing pregnancy rate (49.4% vs 53.6%: RD -4.2%, 95% CI [-13.1; 4.7]) or live birth rate (49.1% vs 52.3%: RD -3.2%, 95% CI [-12; 5.7]). No significant differences were also found according to miscarriage rate (12.4% vs 9.2%: RD 3.2%, 95% CI [-4.3; 10.7]).

LIMITATIONS, REASONS FOR CAUTION

Only iLPS through daily Psc was evaluated. The time for Psc injection was not stated and no serum P4 determinations were performed once the pregnancy was achieved.

WIDER IMPLICATIONS OF THE FINDINGS

Our study provides information regarding an 'opportunity window' for improved ongoing pregnancy rates and miscarriage rates through a daily Psc injection in cases of inadequate P4 levels the day previous to FET (P4 < 10.6 ng/ml) and restored values the day of FET (P4 > 10.6 ng/ml). Only euploid FET under HRT were considered, avoiding one of the main reasons of miscarriage and implantation failure and overcoming confounding factors such as female age, embryo quality or ovarian stimulation protocols.

STUDY FUNDING/COMPETING INTEREST(S)

No external funding was received. B.C. reports personal fees from MSD, Merck Serono, Ferring Pharmaceuticals, IBSA and Gedeon Richter outside the submitted work. N.P. reports grants and personal fees from MSD, Merck Serono, Ferring Pharmaceuticals, Theramex and Besins International and personal fees from IBSA and Gedeon Richter outside the submitted work. The remaining authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

NCT03740568.

The dawn of the future: 30 years from the first biopsy of a human embryo. The detailed history of an ongoing revolution

Following early studies showing no adverse effects, cleavage stage biopsy by zona drilling using acid Tyrode's solution, and removal of single blastomeres for preimplantation genetic testing (PGT) and identification of sex in couples at risk of X-linked disease, was performed by Handyside and colleagues in late 1989, and pregnancies reported in 1990. This method was later used for specific diagnosis of monogenic conditions, and a few years later also for chromosomal structural and/or numerical impairments, thereby establishing a valuable alternative option to prenatal diagnosis. This revolutionary approach in clinical embryology spread worldwide, and several other embryo biopsy strategies developed over three decades in a process that is still ongoing. The rationale of this narrative review is to outline the different biopsy approaches implemented across the years in the workflow of the IVF clinics that provided PGT: their establishment, the first clinical experiences, their downsides, evolution, improvement and standardization. The history ends with a glimpse of the future: minimally/non-invasive PGT and experimental embryo micromanipulation protocols. This grand theme review outlines a timeline of the evolution of embryo biopsy protocols, whose implementation is increasing worldwide together with the increasing application of PGT techniques in IVF. It represents a vade mecum especially for the past, present and upcoming operators and experts in this field to (re)live this history from its dawn to its most likely future.

Inconclusive results in preimplantation genetic testing: go for a second biopsy?

The transition in biopsy timing from blastomere to trophectoderm biopsy has led to a remarkable decrease in the percentage of undiagnosed blastocysts. However, patients with few or no euploid blastocysts can be affected by this residual percentage of diagnosis failure. The aim of this study is to assess whether blastocyst rebiopsy and revitrification is an efficient and safe procedure to be applied in cases of no results after analysis. Fifty-three patients agreed to the warming of 61 blastocysts to perform a second biopsy and PGT-A by aCGH. Only 75.4% of the blastocysts survived, reexpanded, and could be rebiopsied. After the second biopsy and analysis, 95.6% of the blastocysts were successfully diagnosed with an euploidy rate of 65.9%. Eighteen euploid blastocysts were warmed and transferred to 18 patients with a 100% survival and reexpansion rate. Seven clinical pregnancies have been achieved with 4 live births, 1 ongoing pregnancy, and 2 miscarriages. Thus, although few transfers of rebiopsied and revitrified blastocysts have been performed till date, our preliminary results show that this approach is efficient and safe to be applied for undiagnosed blastocysts, as it ultimately allows the transfer of euploid blastocysts and good clinical outcomes.

Transition from blastomere to trophectoderm biopsy: comparing two preimplantation genetic testing for aneuploidies strategies

Shortly after the implementation of comprehensive chromosome screening (CCS) techniques for preimplantation genetic testing for aneuploidies (PGT-A), the discussion about the transition from day 3 to blastocyst stage biopsy was initiated. Trophectoderm biopsy with CCS is meant to overcome the limitations of cleavage-stage biopsy and single-cell analysis. The aim of this study was to assess the results obtained in our PGT-A programme after the implementation of this new strategy. Comparisons between the results obtained in 179 PGT-A cycles with day 3 biopsy (D+3) and fresh embryo transfer, and 204 cycles with trophectoderm biopsy and deferred (frozen–thawed) embryo transfer were established. Fewer embryos were biopsied and a higher euploidy rate was observed in the trophectoderm biopsy group. No differences in implantation (50.3% vs. 61.4%) and clinical pregnancy rate per transfer (56.1% vs. 65.3%) were found. Although the mean number of euploid embryos per cycle did not differ between groups (1.5 ± 1.7 vs. 1.7 ± 1.8), the final number of euploid blastocysts available for transfer per cycle was significantly higher in the trophectoderm biopsy group (1.1 ± 1.3 vs. 1.7 ± 1.8). This factor led to an increased cumulative live birth rate in this last group (34.1% vs. 44.6%). Although both strategies can offer good results, trophectoderm biopsy offers a more robust diagnosis and the intervention is less harmful for the embryos so more euploid blastocysts are finally available for transfer and/or vitrification.

Vitrified blastocysts from Preimplantation Genetic Diagnosis (PGD) as a source for human Embryonic Stem Cell (hESC) derivation

Embryos diagnosed as abnormal in Preimplantation Genetic Diagnosis (PGD) cycles are useful for the establishment of human Embryonic Stem Cells (hESC) lines with genetic disorders. These lines can be helpful for drug screening and for the development of new treatments. Vitrification has proved to be an efficient method to preserve human blastocysts. One hundred and three abnormal or undiagnosed vitrified blastocysts from the PGD programme at Institut Universitari Dexeus were donated for human embryonic stem cell derivation. The overall survival rate after warming was 70.6 %. Our results showed better survival rates when blastocysts have not started the hatching process (initial/expanded 87.8 %, hatching 68.3 % and hatched 27.3 %). Thirty-five blastocysts and 12 partially surviving embryos were seeded. One hESC line with the multiple exostoses type 2 paternal mutation was obtained.

Cryopreservation of mammalian embryos: Advancement of putting life on hold

Rodent transgenesis and human-assisted reproductive programs involve multistep handling of preimplantation embryos. The efficacy of production and quality of results from conventionally scheduled programs are limited by temporal constraints other than the quality and quantities of embryos per se. The emergence of vitrification, a water ice-free cryopreservation technique, as a reliable way to arrest further growth of preimplantation embryos, provides an option to eliminate the time constraint. In this article, current and potential applications of cryopreservation to facilitate laboratory animal experiments, colony management, and human-assisted reproductive programs are reviewed. Carrier devices developed for vitrification in the last two decades are compared with an emphasis on their physical properties that infer cooling rate of samples and sterility assurance. Biological impacts of improved cryopreservation on preimplantation embryos are also discussed.

Slow and ultrarapid cryopreservation of biopsied mouse blastocysts and its effect on DNA integrity index

PURPOSE

To evaluate the effect of slow and ultra-rapid freezing on biopsied blastocysts' DNA integrity.

METHODS

Forty eight mouse blastocysts were biopsied of which 16 were cryopreserved by slowly freezing and 17 by vitrification. Fourteen intact blastocysts were slowly cryopreserved and 24 were vitrified. Eighteen fresh intact blastocysts and fifteen biopsied blastocysts served as controls. The DNA integrity index of all blastocysts was evaluated using (TUNEL) staining and confocal imaging

RESULTS

Both slow freezing and vitrification of biopsied blastocysts induced apoptosis to a similar extent. Biopsying blastocysts before vitrification resulted in less apoptosis than vitrification of intact blastocysts.

CONCLUSION

Slow freezing and vitrification are equal options for preservation of biopsied blastocysts as regards the DNA integrity index (DII). Biopsied blastocysts better tolerate vitrification than intact expanded blastocysts.

Preimplantation genetic diagnosis for mitochondrial DNA disorders: ethical guidance for clinical practice

Although morally acceptable in theory, preimplantation genetic diagnosis (PGD) for mitochondrial DNA (mtDNA) disorders raises several ethical questions in clinical practice. This paper discusses the major conditions for good clinical practice. Our starting point is that PGD for mtDNA mutations should as far as possible be embedded in a scientific research protocol. For every clinical application of PGD for mtDNA disorders, it is not only important to avoid a 'high risk of serious harm' to the future child, but also to consider to what extent it would be possible, desirable and proportional to try to reduce the health risks and minimize harm. The first issue we discuss is oocyte sampling, which may point out whether PGD is feasible for a specific couple. The second issue is whether one blastomere represents the genetic composition of the embryo as a whole -- and how this could (or should) be investigated. The third issue regards the cutoff points below which embryos are considered to be eligible for transfer. We scrutinize how to determine these cutoff points and how to use these cutoff points in clinical practice -- for example, when parents ask to take more or less risks. The fourth issue regards the number of cycles that can (or should) justifiably be carried out to find the best possible embryo. Fifth, we discuss whether follow-up studies should be conducted, particularly the genetic testing of children born after IVF/PGD. Finally, we offer the main information that is required to obtain a truly informed consent.