Hatching status before embryo transfer is not correlated with implantation rate in chromosomally screened blastocysts

Preimplantation genetic testing for aneuploidy: predictive embryonic factors

PURPOSE

In a preimplantation genetic testing for aneuploidy (PGT-A) cycle, does the blastocyst quality before biopsy, or the day of biopsy, or the embryo hatching status have an impact on either euploidy or the rate of embryo survival after freezing?

METHODS

This was a retrospective study including 6130 biopsied blastocysts coming from 1849 PGT-A cycles performed in our center (2016-2022). Embryos were categorized according to the inner cell mass and trophectoderm quality, using Gardner's scoring (excellent: AA; good: AB, BA, BB; poor: AC, CA, BC, CB, CC); the day of biopsy (5 or 6); and their hatching status (fully hatched blastocysts [FHB] or non-fully hatched blastocysts [nFHB]). The independent relationship between each group and both euploidy and survival rate was assessed.

RESULTS

Excellent-quality embryos were more euploid than both good- and poor-quality embryos (52.69%, 39.69%, and 26.21%; p < 0.001), and day 5-biopsied embryos were more euploid than day 6-biopsied embryos (39.98% and 34.80%; p < 0.001). Survival rates of excellent-quality (92.26%) and good-quality (92.47%) embryos were higher than survival rates in the poor-quality group (84.61%) (p = 0.011 and p = 0.002). Day 5-biopsied embryos survived better than day 6-biopsied embryos (93.71% vs. 83.69%; p < 0.001) and FHB had poorer survival than nFHB (78.61% vs. 93.52%; p < 0.001).

CONCLUSIONS

Excellent-quality and day 5-biopsied embryos are more prone to be euploid than good and poor or day 6-biopsied embryos, respectively. Poor-quality, day 6-biopsied embryos, and FHB have significantly lower survival after biopsy and vitrification.

Spontaneously hatching human blastocyst is associated with high development potential and live birth rate in vitrified-warmed single blastocyst transfer: A retrospective cohort study

OBJECTIVE

To investigate the effect of hatching status on predicting pregnancy outcomes in single vitrified-warmed blastocyst transfer (SVBT) by objectively subdividing pre-implantation blastocysts according to hatching status.

METHODS

This retrospective study included 817 SVBT cycles performed between January 2016 and December 2017. Transferred embryos were categorized according to their hatching status as follows: group I (n = 147), non-hatching blastocysts; group II (n = 484), hatching blastocysts; and group III (n = 186), completely hatched blastocysts. Hatching blastocysts (group II) were then classified based on the ratio of the blastocystic diameter outside and inside the zona pellucida into early (n = 185), mid- (n = 103), and late (n = 196) hatching stages. Implantation rate (IR), clinical pregnancy rate (CPR), live birth rate (LBR), multiple pregnancy rate (MPR), miscarriage rate, and neonatal outcomes were evaluated.

RESULTS

For groups I, II, and III, respectively, the results were as follows: IR (28.6%, 43.6%, and 53.8%; P < 0.001), CPR (27.9%, 42.8%, and 53.2%; P < 0.001), and LBR (23.1%, 32.0%, and 42.5%; P < 0.001). Group III had better IR, CPR, and LBR. Among hatching blastocysts, late-hatching blastocysts had the highest IR (33.5%, 46.6%, and 51.5% for early, mid-, and late hatching, respectively; P = 0.002) and CPR (33.0%, 45.6%, and 50.5%; P = 0.002), with a tendency for a higher rate of LBR. Neonatal outcomes were not influenced by the hatching status.

CONCLUSION

Advanced hatching status is positively associated with a higher rate of clinical pregnancy and live birth with no negative effects on neonatal outcomes. Additionally, the quantitative classification of hatching status was found to be predictive of pregnancy outcomes.

Effect of the interval from GnRH administration after ovarian super-stimulation on the recovered oocytes, and effect of the transferred cloned blastocysts on the pregnancy rate and pregnancy loss in dromedary camel

The present study was conducted to evaluate the number and maturity of the recovered oocytes after two intervals of in-vivo maturation. In addition to evaluating the effect of the developmental stage, as well as the number of cloned transferred blastocysts on the pregnancy rate and early pregnancy loss (EPL) in dromedary camel. The donor animals (n = 52) were super-stimulated using a single injection of 3000 IU of eCG followed by GnRH administration for oocyte maturation. Cumulus oocyte complexes (COCs) were collected by transvaginal ultrasound-guided aspiration (OPU) either 24-26 h or 18-20 h after GnRH administration. A fewer number of COCs with a lower percentage of oocyte maturity was observed at 24-26 h in comparison to 18-20 h. The effect of the cloned blastocysts' transferred number and developmental stage on the pregnancy rate and EPL was investigated. The total pregnancy rates at 10 days post-ET, 1 and 2 months were 21.9, 12.4, and 8.6%, respectively. Transfer of two or 3-4 embryos per surrogate was accompanied with a higher pregnancy rate at 1 and 2 months than a single embryo transfer. Rates of EPL were 43.5 and 60.1% at 1 and 2 months of pregnancy, respectively. The transfer of two embryos per surrogate was associated with a lower rate of EPL than ET of a single embryo at 1 and 2 months of pregnancy. Also, the ET of 3-4 embryos per surrogate showed a higher rate of EPL than the ET of two embryos at 2 months of pregnancy. ET of hatching (HG) blastocysts showed higher pregnancy rates and fewer EPL than ET of unhatched (UH) or fully hatched (HD) cloned blastocysts at 1 and 2 months of pregnancy. In conclusion, a high number of in-vivo matured oocytes can be recovered by ultrasound-guided transvaginal OPU from super-stimulated females using 3000 IU eCG and an interval of 18-20 h after GnRH administration. The transfer of two hatching cloned blastocytes per surrogate increases the pregnancy rate and decreases EPL in dromedary camels.

The impact of blastocyst freezing and biopsy on the association of blastocyst morphological parameters with live birth and singleton birthweight

OBJECTIVE

To explore whether the associations of 3 blastocyst morphological parameters, namely, degree of blastocyst expansion (expansion), appearance of trophectoderm (TE) and inner cell mass, with live birth and singleton birth weight are influenced by blastocyst freezing and biopsy.

DESIGN

A retrospective study.

SETTING

An assisted reproductive technology center.

PATIENT(S)

28,515 single blastocyst transfer cycles between January 2014 and August 2019.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Live birth and singleton birth weight.

RESULT(S)

Blastocyst transfer cycles were divided into 4 groups: biopsied blastocyst cycles (biopsied-blast), thawed blastocyst cycles (thawed-blast), blastocyst from thawed cleavage embryo cycles (blast-thawed-D3), and fresh blastocyst cycles (fresh-blast). Subgroup analyses by blastocyst stage (day 5 and day 6) were performed in thawed-blast and blast-thawed-D3. Because almost all blastocysts were biopsied on day 6 and fresh blastocysts were transferred on day 5, the biopsied-blast and fresh-blast were not divided into subgroups. First, the associations between blastocyst morphological parameters and live birth were analyzed. To explore the effect of freezing, we compared day-5 frozen cycles (thawed-blast) vs. day-5 fresh cycles (including fresh-blast and blast-thawed-D3) and day 6 frozen cycles (thawed-blast) vs. day-6 fresh cycles (blast-thawed-D3). Inner cell mass and TE were associated with live birth for day 5 embryos, and only TE affected live birth for day-6 embryos. The associations were the same in frozen cycles and fresh cycles. To explore the effect of biopsy, we compared day-6 biopsied cycles (biopsied-blast) vs. day-6 nonbiopsied cycles (including thawed-blast and blast-thawed-D3). All the 3 parameters were associated with live birth in biopsied-blast, whereas only TE was associated with live birth in nonbiopsied cycles. In addition, the associations between blastocyst morphological parameters and singleton birthweight were analyzed. In the 6 subgroups, expansion stage of day-6 embryos in biopsied-blast and TE grade of day-6 embryos in thawed-blast were associated with birth weight, and there are no associations in other subgroups.

CONCLUSION(S)

The association of blastocyst morphological parameters with live birth may be affected by blastocyst biopsy and/or genetic testing, and its association with birth weight may be affected by blastocyst freezing and biopsy and/or genetic testing.

Freeze all-first versus biopsy-first: A retrospective analysis of frozen blastocyst transfer cycles with preimplantation genetic testing for aneuploidy

Potential use of preimplantation genetic testing for aneuploidy (PGT-A) is increasing. Patients who have excess embryos cryopreserved at the blastocyst stage may desire PGT-A but there is little data available on options for these patients. We compared the efficacy and safety of the timing on the cryopreservation and trophectoderm(TE) biopsy for preimplantation genetic testing for aneuploidy (PGT-A) program associated with the better outcomes after frozen blastocyst transfer. Retrospective analysis of patients who underwent PGT-A cycles from January 2016 to December 2019 was carried out. 2684 blastocysts from cycles were subjected to TE biopsy for performing array comparative genomic hybridization test and Next-generation sequencing. All cycles were divided into two according to the timing of biopsy: biopsy-first (n = 211 cases/ 232 transfers) versus freeze all-first (n = 327 cases/ 415 transfers). In the biopsy-first group, embryos were cultured to expanded blastocyst and proceed to TE biopsy on day 5 or day 6 followed by cryopreservation. In the freeze all-first, blastocysts were vitrified and warmed before biopsy. Rates of clinical pregnancy (52.3% vs. 38.7%, P = 0.09) and ongoing pregnancy (44.3% vs. 34.5%, P = 0.07) in biopsy-first were significantly higher than those in freeze all-first. Biopsy-first showed comparable miscarriage rate with freeze all-first (15.2% (33/217) vs.11.1% (10/90), respectively). Rate ratio (RR) for clinical pregnancy was lower in freeze all-first group (adjusted RR = 0.78, 95% confidence interval: 0.65, 0.93). The RRs for miscarriage and live birth was also lower but it did not reach statistical significance. Our result supported performing TE biopsy of blastocyst for PGT-A before vitrification and warming. This finding would contribute to more evidence-based decision in PGT-A cycles.

Euploid day 7 blastocysts of infertility patients with only slow embryo development have reduced implantation potential

RESEARCH QUESTION

What is the reproductive potential of embryos that achieve blastulation on day 7 followed by preimplantation genetic testing for aneuploidies (PGT-A) for infertility patients with slow embryo development?

DESIGN

This was a retrospective cohort study in a private IVF clinic of consecutive female infertility patients (n = 2966) aged 24-48 (36.3 ± 3.8) years who underwent frozen embryo transfer (FET) of a single euploid blastocyst.

RESULTS

The women underwent single euploid FET of an embryo that achieved blastulation on day 5 (n = 1880), day 6 (n = 986) or day 7 (n = 100). Day 7 embryos resulted in lower implantation and live birth rates compared with both day 5 and day 6 embryos (P < 0.001). The day 5, day 6 and day 7 groups had 68.5%, 55.2% and 36.0% live birth rates, respectively. The day 7 group was older than the day 5 group (P < 0.001); comparing age-matched cohorts, the day 7 group still had lower implantation and live birth rates (P < 0.0001 and P < 0.001, respectively). Embryo grade was unrelated to live birth rates. Day 7 embryos of expansion grade 5 or 6 or trophectoderm grade A were more likely to be euploid compared with expansion grade 3 or trophectoderm grade B.

CONCLUSIONS

Euploid day 7 embryos represented reduced implantation potential, even when controlling for maternal age. Of all day 7 embryos that underwent PGT-A, euploidy was associated with expansion grade 5 or 6 and trophectoderm grade A. These results can help providers manage patient expectations in cases where infertile women have slow embryo development.

Factors associated with vitrification-warming survival in 6167 euploid blastocysts

PURPOSE

To understand the clinical factors associated with embryo survival after vitrification in a cohort of human blastocysts screened by preimplantation genetic testing for aneuploidy (PGT-A).

METHODS

Patient demographic, embryo, and cycle characteristics associated with failed euploid blastocyst survival were compared in a cohort of women (n = 6167) who underwent IVF-PGT-A.

RESULTS

Compared to those that survived warming, vitrified euploid embryos that failed to survive after warming came from IVF cycles with significantly higher estradiol levels at time of surge (2754.8 ± 1390.2 vs. 2523.1 ± 1190.6 pg/mL, p = 0.03), number of oocytes retrieved (19.6 ± 10.7 vs. 17.5 ± 9.8, p = 0.005), and basal antral follicle count (BAFC) (15.3 ± 8.5 vs. 13.9 ± 7.2, p = 0.05). Euploid embryos were less likely to survive warming if they came from cycles before 2015 (24.6% vs. 13.2%, p < 0.001), were cryopreserved on day 7 versus day 5 or 6 (9.1% vs. 3.0%, p < 0.001), underwent two trophectoderm biopsies (6.9% vs. 2.3%, p < 0.001), had a grade C inner cell mass (15.4% vs. 7.7%, p < 0.001), or were fully hatched (41.1% vs. 12.2%, p < 0.001). In the multivariate model, which controlled for relevant confounders, the association between decreased survival and increased BAFC, year of IVF cycle, double trophectoderm biopsy, and fully hatched blastocysts remained statistically significant.

CONCLUSION

Euploid embryos that are fully hatched at time of vitrification, come from patients with high ovarian reserve, or require repeat trophectoderm biopsy are less likely to survive vitrification-warming. Our results provide a framework for reproductive counseling and offer realistic expectations to patients about the number of embryos needed to achieve family building goals.

Day 5 versus Day 6 blastocyst transfers: a systematic review and meta-analysis of clinical outcomes

STUDY QUESTION

Is there a difference in clinical pregnancy and live birth rates (LBRs) between blastocysts developing on Day 5 (D5) and blastocysts developing on Day 6 (D6) following fresh and frozen transfers?

SUMMARY ANSWER

D5 blastocyst transfers (BTs) present higher clinical pregnancy and LBRs than D6 in both fresh and frozen transfers.

WHAT IS KNOWN ALREADY

BT is increasingly popular in assisted reproductive technology (ART) centers today. To our knowledge, no meta-analysis has focused on clinical outcomes in both fresh and frozen BT. Concerning frozen blastocysts, one meta-analysis in 2010 found no significant difference in pregnancy outcomes between D5 and D6 BT. Since then, ART practices have evolved particularly with the wide use of vitrification, and more articles comparing D5 and D6 BT cycles have been published and described conflicting results.

STUDY DESIGN, SIZE, DURATION

Systematic review and meta-analysis of published controlled studies. Searches were conducted from 2005 to February 2018 on MEDLINE and Cochrane Library and from 2005 to May 2017 on EMBASE, Eudract and clinicaltrials.gov, using the following search terms: blastocyst, Day 5, Day 6, pregnancy, implantation, live birth and embryo transfer (ET).

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 47 full-text articles were preselected from 808 references, based on title and abstract and assessed utilizing the Newcastle-Ottowa Quality Assessment Scales. Study selection and data extraction were carried out by two independent reviewers according to Cochrane methods. Random-effect meta-analysis was performed on all data (overall analysis) followed by subgroup analysis (fresh, vitrified/warmed, slow frozen/thawed).

MAIN RESULTS AND THE ROLE OF CHANCE

Data from 29 relevant articles were extracted and integrated in the meta-analysis. Meta-analysis of the 23 studies that reported clinical pregnancy rate (CPR) as an outcome, including overall fresh and/or frozen ET cycles, showed a significantly higher CPR following D5 ET compared with D6 ET (risk ratio (RR) = 1.27, 95% CI: 1.15-1.39, P < 0.001). For CPR, calculated subgroup RRs were 2.38 (95% CI: 1.74-3.24, P < 0.001) for fresh BT; 1.27 (95% CI: 1.16-1.39, P < 0.001) for vitrified/warmed BT; and 1.15 (95% CI: 0.93-1.41, P = 0.20) for slow frozen/thawed BT. LBR was also significantly higher after D5 BT (overall RR = 1.50 (95% CI: 1.32-1.69), P < 0.001). The LBR calculated RRs for subgroups were 1.74 (95% CI: 1.37-2.20, P < 0.001) for fresh BT; 1.38 (95% CI: 1.23-1.56, P < 0.001) for vitrified/warmed BT; and 1.44 (95% CI: 0.70-2.96, P = 0.32) for slow frozen/thawed BT. Sensitivity analysis led to similar results and conclusions: CPR and LBR were significantly higher following D5 compared to D6 BT.

LIMITATIONS, REASONS FOR CAUTION

The validity of meta-analysis results depends mainly on the quality and the number of the published studies available. Indeed, this meta-analysis included no randomized controlled trial (RCT). Slow frozen/thawed subgroups showed substantial heterogeneity.

WIDER IMPLICATIONS OF THE FINDINGS

In regards to the results of this original meta-analysis, ART practitioners should preferably transfer D5 rather than D6 blastocysts in both fresh and frozen cycles. Further RCTs are needed to address the question of whether D6 embryos should be transferred in a fresh or a frozen cycle.

STUDY FUNDING/COMPETING INTEREST(S)

This work was sponsored by an unrestricted grant from GEDEON RICHTER France. The authors have no competing interests to declare.

REGISTRATION NUMBER

CRD42018080151.

Impact of post-warming culture duration on clinical outcomes of vitrified good-quality blastocyst transfers: a prospective randomized study

OBJECTIVE

To determine whether post-warming culture duration (1 hour vs. 18 hours) influences implantation rates (IRs) of good-quality blastocysts (GQB) in a good-prognosis population.

DESIGN

Prospective interventional randomized study.

SETTING

University hospital.

PATIENT(S)

One hundred sixty-two GQB transfers.

INTERVENTION(S)

Patients' vitrified blastocysts were randomly allocated to group A, warming on the day before transfer (n = 81), or B, warming on the day of transfer (n = 81).

MAIN OUTCOME MEASURE(S)

IR, live birth rate, reexpansion degree, and quality after warming and immediately before transfer.

RESULT(S)

Quality of the warmed and transferred blastocysts was similar (respectively, 39.1% and 32.7% top quality [≥B4AA/AB/BA] in group A vs. 41.7 and 42.2% in group B). In group A, 14 of 102 blastocysts (12.2%) appeared to be unsuitable for transfer, versus only 1 of 103 (0.9%) in group B, thus leading to an additional warming. As expected, reexpansion degree just before transfer was higher in group A (0.90 vs. 0.70). Likewise, the proportion of hatched blastocysts before transfer was higher after a longer culture period (38.6% in group A vs. 12.7% in group B). IRs were similar (38.0% in group A vs. 36% in group B), as were live birth rates (35.8% in group A vs. 34.6% in group B).

CONCLUSION(S)

IRs were not different, whatever the duration of post-warming culture of GQB. Both warming strategies could be applied to good-prognosis patients to optimize the laboratory workflow without any detrimental effect.

Ovarian stimulation for preimplantation genetic testing

A narrative review of the management of controlled ovarian stimulation in patients undergoing preimplantation genetic testing is presented. An electronic search was performed to identify research publications that addressed ovarian stimulation and preimplantation genetic testing published until December 2017. Studies were classified in decreasing categories: randomized controlled trials, prospective controlled trials, prospective non-controlled trials, retrospective studies and experimental studies. The aim of controlled ovarian stimulation has shifted from obtaining embryos available for transfer to yielding the maximum embryos available for biopsy to increase the odds of achieving one euploid embryo available for transfer, without the distress of inducing ovarian hyperstimulation syndrome or inadequate endometrium receptivity as vitrification and deferred embryo transfer usually will be planned. The present narrative review summarizes all treatment-related variables as well as stimulation strategies after controlled ovarian stimulation that could help patients undergoing an in vitro fertilization cycle coupled with preimplantation genetic testing, including the number of oocytes needed to achieve one healthy live birth, oral contraceptive pill usage, the role of mild ovarian stimulation or random-start stimulation, the stimulation protocol and type of gonadotropin of choice, the novel progesterone protocols, agonist or dual trigger as a final oocyte maturation trigger, the accumulation of oocytes/embryos and the optimal interval before proceeding with a subsequent controlled ovarian stimulation or the optimal medication to link stimulation cycles. The discussion is being presented according to how questions are posed in clinical practice. The aim of ovarian stimulation has shifted from obtaining embryos available for transfer to yielding the maximum embryos available for biopsy to increase the odds of achieving one euploid embryo available for transfer.

The endometrium during and after ovarian hyperstimulation and the role of segmentation of infertility treatment

Controlled ovarian hyperstimulation (COH) is a crucial part of assisted reproductive technologies (ART) that resulted in a substantial increase in pregnancy rates from in vitro fertilization (IVF). However, in spite of the apparent benefit of COH on an increase in the number of follicles and the number of oocytes retrieved, allowing for extended embryo culture and enabling the selection of the best quality embryo for transfer, several reports has shown that the supraphysiologic hormonal levels may indeed have a detrimental effect at the endometrial level. The current article revises the pathophysiological mechanisms through which ovarian stimulation may negatively affect endometrial receptivity. Also, the evidence is analyzed explaining how segmentation of IVF treatment may allow us to overcome the deleterious effects of hyperstimulation on endometrial receptivity. Deferred embryo transfer may be performed in a more physiologic uterine environment in a subsequent cycle, improve endometrial receptivity, decrease uterine contractility, diminishes the impact of premature luteinization and allow individualized stimulation according to the level of response.