Prognostic value of triploid zygotes on intracytoplasmic sperm injection outcomes

Usefulness of combined NGS and QF-PCR analysis for product of conception karyotyping

Purpose

Since chromosomal abnormalities can be detected in more than half of miscarriages, cytogenetic testing of the product of conception (POC) can provide important information when preparing for a subsequent pregnancy. Conventional karyotyping is the common diagnostic method for a POC but can be problematic due to the need for cell culture.

Methods

We here conducted shallow whole-genome sequencing (sWGS) using next-generation sequencing (NGS) for alternative POC cytogenomic analysis. Since female euploidy samples can include 69,XXX triploidy, additional QF-PCR was performed in these cases.

Results

We here analyzed POC samples from miscarriages in 300 assisted reproductive technology (ART) pregnancies and detected chromosomal abnormalities in 201 instances (67.0%). Autosomal aneuploidy (151 cases, 50.3%) was the most frequent abnormality, consistent with prior conventional karyotyping data. Mosaic aneuploidy was detected in seven cases (2.0%). Notably, the frequency of triploidy was 2.3%, 10-fold lower than the reported frequency in non-ART pregnancies. Structural rearrangements were identified in nine samples (3%), but there was no case of segmental mosaicism.

Conclusions

These data suggest that NGS-based sWGS, with the aid of QF-PCR, is a viable alternative karyotyping procedure that does not require cell culture. This method could also assist with genetic counseling for couples who undergoes embryo selection based on PGT-A data.

The usefulness of metaphase I oocytes in women who undergo controlled ovarian hyperstimulation for intracytoplasmic sperm injection

Objective:

The aim of this study was to evaluate the fertilization and blastocyst formation rates of oocytes in metaphase I (MI) obtained from women who underwent controlled ovarian hyperstimulation (COH) for intracytoplasmic injection.

Methods:

A prospective cohort study that included women from whom at least 1 MI and 1 MII oocyte were obtained after COH was performed. We collected 1,907 oocytes from 164 women (1291 MII, 352 MI and 258 prophase I or atretic). After oocyte classification, the MII and MI oocytes were incubated for 4 hours.

Results:

After 4 hours, the rescue maturation rate was 57.2%; 205 MI oocytes matured to MII oocytes in vitro (rescued MI-MII group), and 153 remained in MI (arrested MI group). The normal fertilization rates were directly associated with oocyte maturation, with rates of 79.1%, 60.2%, and 31.9% in MII, MI-MII and MI oocytes, respectively (p<0.001). Group arrested MI had an odds ratio (OR) of 7.6 (CI 5.2 - 11.2, p<0.001) for abnormal fertilization compared with Group MII. The blastocyst formation rate was directly associated with oocyte maturation, at 36.4% for MII, 11.4% for MI-MII and 0.6% for MI.

Conclusion:

Oocytes collected at the MI stage after OCH that did not mature to MII after rescue maturation had a blastocyst formation rate of only 0.6%, while those in MII and MI-MII had rates of 36.4% and 11.4%, respectively. However, we found a pregnancy with the birth of a healthy baby from a blastocyst formed after intracytoplasmic sperm injection (ICSI) of an MI oocyte.

Effects of three pro-nuclei (3PN) incidence on laboratory and clinical outcomes after early rescue intracytoplasmic sperm injection (rescue-ICSI): an analysis of a 5-year period

OBJECTIVES

We aimed to explore the effect of three pro-nuclei (3PN) incidence on laboratory and clinical outcomes after early rescue intracytoplasmic sperm injection (rescue-ICSI).

METHODS

This study included 509 early rescue-ICSI cycles from February 2014 to February 2019. The patients were divided into 3PN = 0% (394 cycles) and 3PN > 0% (115 cycles) group. Main outcomes compared were good quality embryo, available embryo, implantation (IR), clinical pregnancy (CPR), abortion (AR) and live birth rates (LBR).

RESULTS

There were no significant differences in the basal characteristics between two groups (p > .05). We observed that 3PN = 0% and 3PN > 0% groups had similar good quality embryo (47.02 versus 46.80%; p = .917) and available embryo (83.28 versus 81.37%; p = .247) rates. Our results showed that the IR (47.26 versus 51.05%; p = .357), CPR (61.17 versus 66.08%; p = .338) and LBR (52.80 versus 50.43%; p = .656) were comparable between 3PN = 0% and 3PN > 0% groups. The 3PN = 0% group showed significantly lower AR than that in the 3PN > 0% group (11.20 versus 21.05%; p = .029; OR 2.114; 95% CI 1.069-4.178).

CONCLUSIONS

3PN incidence made negative effects on the clinical outcomes after early rescue-ICSI.

Thoughts on the popularity of ICSI

Purpose

Intracytoplasmic sperm injection (ICSI) is the most widely utilized assisted reproductive technique (ART) worldwide. In this feature, we review the early assisted fertilization attempts that eventually led to the development of ICSI, and discuss its current utilization in cases of male and non-male factor infertility.

Methods

We researched the literature related to the development, indications, and current use of ICSI, such as sperm structural abnormalities, male genetic indications, surgically retrieved sperm, high sperm chromatin fragmentation, oocyte dysmorphism, and preimplantation genetic testing (PGT). We also describe the potential future applications of ICSI.

Results

This review summarizes the early micromanipulation techniques that led to the inception of ICSI. We also explore its current indications, including non-male factor infertility, where its use is more controversial. Finally, we consider the benefits of future advancements in reproductive biology that may incorporate ICSI, such as in vitro spermatogenesis, neogametogenesis, and heritable genome editing.

Conclusion

The versatility, consistency, and reliability of ICSI have made it the most prevalently utilized ART procedure worldwide.

Attempts for Generation of Embryonic Stem Cells from Human Embryos Following In Vitro Embryo Twinning

In vitro embryo twinning can be used to increase the number of the human embryos available for production of human embryonic stem cell (hESC) lines. The aim of this study was to generate hESCs following the production of the twin embryos by in vitro embryo splitting procedures. In total 21 chromosomally abnormal (three pronuclei) embryos underwent in vitro embryo twinning and were allowed to develop to the blastocyst stage. As a result, 42 twin embryos were obtained, of which 24 developed to blastocyst stage. Using micromanipulation technique, the zona-free blastocysts were recovered and plated onto mitotically inactivated Yazd human foreskin fibroblast (Batch18; YhFF#18) feeder layers in microdrops. After 3 to 5 days of blastocyst culture onto human foreskin fibroblast feeder layers, the hESC-like outgrowths were passaged onto new feeders in microdrops. The initial outgrowths of hESC-like cells were generated, and cells were proliferated, passaged, and some of them expressed hESC and trophoblastic markers; however, no cell lines were established. This might be due to the low cell number and poor quality of inner cell mass within these twin blastocysts. In vitro embryo twinning by increasing the number of the human embryos could be useful in the future for the generation of new pluripotent stem cell lines. However, the challenge remains to optimize the methods.

Effects of high three pro-nuclei (3PN) proportion incidence on clinical outcomes in the fresh cleavage-stage and blastocyst-stage embryo transfer (ET) cycles

OBJECTIVES

The aim of this study was to explore the effect of three pro-nuclei (3PN) incidence on clinical outcomes in the fresh cleavage-stage embryo transfer (CSET) and blastocyst-stage embryo transfer (BSET) cycles.

METHODS

This retrospective cohort study included 1427 CSET cycles, 632 BSET cycles, and 313 elective single BSET cycles from January 2013 to June 2015. The patients were divided into two groups as follows: Group 1 included patients with no 3PN zygotes and Group 2 included patients with >20% 3PN zygotes.

RESULTS

We observed that the fertilization rate was significantly lower in 3PN = 0% than 3PN > 20% group (p < 0.05), but the day-3 grade I + II embryo and day-3 grade I + II + III embryo rates were not significantly different between 3PN = 0% and 3PN > 20% group (p > 0.05). Interestingly, in the CSET, the implantation (42.87% and 41.76%, p = 0.585) and clinical pregnancy (59.94% and 58.25%, p = 0.538) rates were not significantly different between two groups. In the BSET, the implantation (61.93% and 49.62%, p < 0.001) and clinical pregnancy rates (69.45% and 61.02%, p = 0.043) were significantly higher in 3PN = 0% than 3PN > 20% group. In the elective single BSET, the implantation (68.91% and 61.33%, p = 0.223) and clinical pregnancy rates (68.48% and 61.33%, p = 0.251) were higher in 3PN = 0% than 3PN > 20% group, but there was no significant difference.

CONCLUSIONS

We concluded that a high 3PN incidence may predict poor outcomes in BSET but not CSET cleavage-stage.

Effects of three pro-nuclei (3PN) proportion incidence on clinical outcomes of patients with lower retrieved oocytes in the fresh cleavage-stage embryo transfer (ET) cycles

PURPOSE

To analyze the three pro-nuclei (3PN) incidence on clinical outcomes of patients with lower retrieved oocytes in the fresh cleavage-stage embryo transfer (ET) cycles.

METHODS

This study included 1200 fresh cleavage-stage ET cycles from January 2013 to June 2015. The patients were divided into 3PN = 0% (773 cycles) and 3PN > 0% (427 cycles) group. Main outcomes compared were fertilization, cleavage, normal fertilization, good quality embryo, implantation, clinical pregnancy, and early abortion rate.

RESULTS

We observed that there was no significant difference in female's age, the number of retrieved oocytes, the number of transferred embryos, the number of good quality embryos, endometrial thickness, infertile time, basal serum follicle-stimulating hormone, and E2 value between two groups (p > 0.05). The fertilization (89.43 versus 83.90%, p < 0.001) and cleavage (98.34 versus 97.19%, p = 0.048) rates were significantly higher in 3PN > 0% than 3PN = 0% group. However, the normal fertilization (70.05 versus 50.67%, p < 0.001), good quality embryos (37.11 versus 26.47%, p < 0.001), and clinical pregnancy (49.81 versus 43.79%, p = 0.046) rates were significantly higher in 3PN = 0% than 3PN > 0% group. The implantation (35.88 versus 33.78%, p = 0.333) and early abortion (8.83 versus 10.70%, p = 0.474) rates were not significantly different between two groups.

CONCLUSION

3PN incidence might make a negative effect on clinical outcomes for patients with lower retrieved oocytes in the fresh cleavage-stage ET cycles.

Prognostic value of three pro-nuclei (3PN) incidence in elective single blastocyst-stage embryo transfer

OBJECTIVES

To investigate whether 3PN incidence could lead to a worse pregnancy outcome of elective single blastocyst stage embryo transfer (eSBET).

METHODS

This study included 706 eSBET cycles from January 2013 to March 2015. The patients were divided into two groups as follows: group 1 included 286 patients with no 3PN zygotes and group 2 included 420 patients with 3PN zygotes.

MAIN OUTCOME MEASURE

female age, endometrial thickness, infertility duration, type of infertility, main etiology of infertility, clinical pregnancy and abortion rate.

RESULTS

We observed that there was no significant difference in female age, endometrial thickness, infertility duration and abortion rate between two groups. It's worth noting that the clinical pregnancy rate in 3PN > 0% group was significantly lower than 3PN = 0 group (P = 0.021).

CONCLUSIONS

3PN incidence might make anegative effect on pregnancy outcomes in elective single blastocyst stage embryo transfer.

Effects of triploidy incidence on clinical outcomes for IVF-ET cycles in different ovarian stimulation protocols

PURPOSE

To discuss the relationship between triploidy incidence and clinical outcomes of embryos derived from normally fertilized oocytes from the same cohort for in vitro fertilization-embryo transfer (IVF-ET) cycles in different ovarian stimulation protocol.

METHODS

This study included 2070 in vitro fertilization (IVF) cycles with long-term protocol, 802 IVF cycles with ultra short-term protocol and 508 IVF-D (in vitro fertilization by donor semen) cycles with long-term protocol from January 2013 to September 2014. According to the different 3PN rate, patients were divided into three groups as follows: Group 1 included patients with 0% 3PN zygotes, Group 2 included patients with 1-25% 3PN zygotes and Group 3 included patients with >25% 3PN zygotes.

MAIN OUTCOME MEASURE

female age, no. of retrieved oocytes, normal fertilization rate, day-3 grade I + II embryos rate, day-3 grade I + II + III embryos rate, implantation rate, pregnancy rate and early abortion rate.

RESULTS

Triploidy cycle incidence rate in IVF and IVF-D cycles with long-term protocol were significantly higher than in IVF cycles with ultra short-term protocol (p < 0.001). Triploidy fertilization rate found no significant difference between the three groups (p > 0.05). In three protocols, normal fertilization rate in 3PN = 0% and 3PN = 1-25% groups were significantly higher compared to 3PN > 25% group (p < 0.001). In IVF cycles with long-term protocol, the day-3 grade I + II embryos, implantation and pregnancy rate in 3PN > 25% group were significantly lower than other two groups (p < 0.05). The day-3 grade I + II + III embryos and early abortion rate found no significant difference between the three groups (p > 0.05). In IVF cycles with ultra short-term protocol, there were no significant differences found in day-3 grade I + II embryos, day-3 grade I + II + III embryos, implantation, pregnancy and early abortion rate (p > 0.05). In IVF-D cycles with long-term protocol, the day-3 grade I + II embryos, day-3 grade I + II + III embryos and implantation rate in 3PN > 25% group were significantly lower than other two groups (p < 0.05). The pregnancy and early abortion rates found no significant difference in the three groups (p > 0.05).

CONCLUSION

We observed that high proportion of triploid zygotes made a negative effect on clinical outcomes for IVF-ET cycles with long-term protocol.

Evidence of Selection against Complex Mitotic-Origin Aneuploidy during Preimplantation Development

Whole-chromosome imbalances affect over half of early human embryos and are the leading cause of pregnancy loss. While these errors frequently arise in oocyte meiosis, many such whole-chromosome abnormalities affecting cleavage-stage embryos are the result of chromosome missegregation occurring during the initial mitotic cell divisions. The first wave of zygotic genome activation at the 4-8 cell stage results in the arrest of a large proportion of embryos, the vast majority of which contain whole-chromosome abnormalities. Thus, the full spectrum of meiotic and mitotic errors can only be detected by sampling after the initial cell divisions, but prior to this selective filter. Here, we apply 24-chromosome preimplantation genetic screening (PGS) to 28,052 single-cell day-3 blastomere biopsies and 18,387 multi-cell day-5 trophectoderm biopsies from 6,366 in vitro fertilization (IVF) cycles. We precisely characterize the rates and patterns of whole-chromosome abnormalities at each developmental stage and distinguish errors of meiotic and mitotic origin without embryo disaggregation, based on informative chromosomal signatures. We show that mitotic errors frequently involve multiple chromosome losses that are not biased toward maternal or paternal homologs. This outcome is characteristic of spindle abnormalities and chaotic cell division detected in previous studies. In contrast to meiotic errors, our data also show that mitotic errors are not significantly associated with maternal age. PGS patients referred due to previous IVF failure had elevated rates of mitotic error, while patients referred due to recurrent pregnancy loss had elevated rates of meiotic error, controlling for maternal age. These results support the conclusion that mitotic error is the predominant mechanism contributing to pregnancy losses occurring prior to blastocyst formation. This high-resolution view of the full spectrum of whole-chromosome abnormalities affecting early embryos provides insight into the cytogenetic mechanisms underlying their formation and the consequences for human fertility.

Three pro-nuclei (3PN) incidence factors and clinical outcomes: a retrospective study from the fresh embryo transfer of in vitro fertilization with donor sperm (IVF-D)

OBJECTIVES

The aim of this study was to explore the main factors of 3PN incidence and determine whether the presence of 3PN could lead to a worse pregnancy outcome.

METHODS

This study included 508 IVF-D (in vitro fertilization with donor sperm) cycles from January 2013 to September 2014. The patients were divided into three groups as follows: group 1 included patients with no 3PN zygotes, group 2 included patients with 1%-25% 3PN zygotes and group 3 included patients with > 25% 3PN zygotes.

RESULTS

We observed that more retrieved oocytes and higher HCG day peak E2 value could result in 3PN incidence more easily. When the 3PN zygotes rate was > 25%, the percentages of normal fertilization (68.4% and 66.3% and 46.4%, P < 0.001), day 3 grade I+II embryos (41.2% and 38.6% and 25.8%, P < 0.001), day 3 grade I+II+III embryos (68.7% and 65.2% and 61.4%, P = 0.032) and implantation rates (52.1% and 50.8% and 45.4%, P = 0.026) were significantly lower than that in the other two groups respectively. The pregnancy rate was lower in 3PN > 25% group than that in the other two groups but there was no significant difference (65.2% and 66.7% and 55.6%, P = 0.266). The cleavage (98.3% and 97.2% and 98.2%, P = 0.063) and early abortion (7.1% and 8.0% and 8.6%, P = 0.930) rate were identical among three groups.

CONCLUSIONS

More retrieved oocytes and higher HCG day peak E2 value could result in 3PN incidence more easily. Interestingly, normal fertilization rate, day-3 grade I+II embryos rate, day-3 grade I+II+III embryos rate and implantation rate were significantly lower in IVF-D cycles with a 3PN incidence of > 25%. The number of day-3 grade I+II embryos might be a key factor for pregnancy in IVF-D cycles with a 3PN incidence of > 25%.