The migration speed of nucleolar precursor bodies in pronuclei affects in vitro fertilization-derived human embryo ploidy status and live birth.

Purpose: To study the relationship between clinical outcomes after assisted reproduction and the migration speed of nucleolus precursor bodies (NPBs) in male and female pronuclei (mPN; fPN). Methods: NPB migration speed, embryo ploidy status, and live birth (LB) were retrospectively analyzed in IVF-derived zygotes. The central coordinates of the mPN, fPN, and NPBs were noted at multiple timepoints. The migration distance of NPBs between two sequential images was measured to calculate NPB migration speed. Results: The NPB migration speeds in mPN and fPN were significantly faster in euploid zygotes than in aneuploid zygotes. In multivariate logistic analysis, NPB migration speed in mPN and the female age were associated with euploidy. The NPB migration speeds in mPN and fPN were also significantly faster in zygotes that led to LB than in zygotes that led to no pregnancy. In a receiver operating characteristic curve analysis of LB by NPB migration speed in mPN, the cut-off value was 3.74 µm/h (AUC: 0.825, 95%CI: 0.688-0.963). When the zygotes were categorized by this cut-off value, there were significantly more LBs in zygotes with migration speed ≥ the cut-off (78.9% vs. 21.1%). Conclusions: Zygotes with quickly migrating NPBs demonstrated the developmental potential to become a baby.

Outcome of in vitro fertilization cycles with automatic time-lapse instrumentation combined with the early embryo viability assessment score.

AIM: To evaluate whether embryo selection using the early embryo viability assessment (EEVA) score increases the ongoing pregnancy rate of in vitro fertilization and intracytoplasmic sperm injection patients. METHODS: One hundred eighty-one patients whose serum anti mullerian hormone (AMH) level was greater than 0.5 ng/µL were enrolled in the study. All patients received oocyte retrieval repeatedly from June 2017 to January 2019. Transferred embryos were selected using the EEVA score and Veeck's criteria. We investigated the blastocyst rate according to the EEVA score and Veeck's criteria and also evaluated the clinical outcome following embryo transfer of the blastocysts. RESULTS: Blastocyst development rate (48.7%) and high-quality blastocyst (42.4%) of Veeck 1 was statistically higher than others. The blastocyst rate (71.4%) and high-quality blastocyst rate (60.0%) for EEVA 1 was the highest, and a correlation between the EEVA score and the blastocyst rate was also identified in cases younger than 40 years. Blastocyst rate of EEVA 1 + 2 (69.8% 208/298) was statistically higher than that of Veeck 1 + 2 (40.1% 317/791) (p < 0.05) and high-quality blastocyst rate of EEVA 1 + 2 (50.0% 104/208) was also higher than that of Veeck 1 + 2 (36.6% 117/320) (p < 0.05). However, there was a significant correlation between EEVA and the pregnancy rate and pregnancy rate of EEVA 1 + 2 showed no statistical difference compared with Veeck 1 + 2. CONCLUSIONS: Although it remains to be answered whether a computer can substitute Veeck's classification, the EEVA score could be a viable alternative to predict the blastocyst rate and to select those high-potential embryos that improve the pregnancy rate.

Migration speed of nucleolus precursor bodies in human male pronuclei: a novel parameter for predicting live birth.

PURPOSE: To study the relationship between the migration speed of nucleolus precursor bodies (NPBs) in male and female pronuclei (mPN; fPN) and human embryo development during assisted reproduction. METHODS: The migration speed of 263 NPBs from 47 zygotes was quantitated, and embryonic development was observed until the blastocyst stage. The central coordinates of mPN, fPN, and NPBs were noted at multiple timepoints. Then, the distance traveled by the NPBs between two sequential images was measured, and migration speed was calculated. Additionally, we investigated the relationship between NPB migration speed and ploidy status (N = 33) or live birth/ongoing pregnancy (LB/OP) (N = 60) after assisted reproduction. RESULTS: The NPB migration speed in both mPN and fPN was significantly faster in the zygotes that developed into blastocysts (N = 25) than that in the zygotes that arrested (N = 22). The timing of blastulation was negatively correlated with NPB migration speed in the mPN. Faster NPB migration was significantly correlated with LB/OP. In multivariate logistic analysis, NPB migration speed in the mPN was the only morphokinetic parameter associated with LB/OP. In a receiver-operating characteristic curve analysis of LB/OP by the NPB migration speed in the mPN, the cut-off value was 4.56 µm/h. When this cut-off value was applied to blastocysts with preimplantation genetic testing for aneuploidy, 100% of the blastocysts faster than or equal to the cut-off value were euploid. CONCLUSION: The NPBs migrated faster in zygotes having the potential to develop into a blastocyst, and eventually into a baby. This predictor could be an attractive marker for non-invasive embryo selection.

Association of follicular fluid volume with membrane stretchability of human metaphase II oocytes following the gonadotropin-releasing hormone agonist protocol during intracytoplasmic sperm injection.

PURPOSE: The authors previously revealed the association of the follicular fluid (FF) volume with oolemma stretchability following the gonadotropin-releasing hormone (GnRH) antagonist protocol during intracytoplasmic sperm injection (ICSI). However, the impact of the GnRH agonist protocol on oolemma stretchability remains unclear. METHODS: Data that were obtained from 74 ICSI cycles were reviewed retrospectively. Controlled ovarian stimulation was performed in accordance with the short GnRH agonist protocol. Each follicle was individually aspirated and assigned to one of six groups, according to the FF volume. The oolemma stretchability during ICSI was evaluated by using a mechanical stimulus for oolemma penetration; that is, oolemma penetration with or without aspiration (high vs low stretchability, respectively). RESULTS: The incidence of low oolemma stretchability was significantly higher in the <1.0 mL group than that in the ≥1.0 mL group. The normal fertilization rate was significantly lower in the <1.0 mL group than that in the 2.0-<3.0 mL group. The rate of blastocyst development was lower in the <1.0 mL group than that in the 3.0-<4.0 mL group. CONCLUSION: The FF volume potentially was associated with metaphase II oolemma stretchability, fertilization, and blastocyst development.

The association of follicular fluid volume with human oolemma stretchability during intracytoplasmic sperm injection.

OBJECTIVE: Oocyte degeneration often occurs after intracytoplasmic sperm injection (ICSI), and the risk factor is low-quality oocytes. The follicular fluid (FF) provides a crucial microenvironment for oocyte development. We investigated the relationships between the FF volume aspirated from individual follicles and oocyte retrieval, oocyte maturity, oolemma stretchability, fertilization, and development. METHODS: This retrospective study included data obtained from 229 ICSI cycles. Ovarian stimulation was performed according to a gonadotropin-releasing hormone antagonist protocol. Each follicle was individually aspirated and divided into six groups according to FF volume (<1.0, 1.0 to <2.0, 2.0 to <3.0, 3.0 to <4.0, 4.0 to <5.0, and ≥5.0 mL). Oolemma stretchability during ICSI was evaluated using a mechanical stimulus for oolemma penetration, that is, the stretchability was assessed by oolemma penetration with aspiration (high stretchability) or without aspiration (low stretchability). RESULTS: Oocyte retrieval rates were significantly lower in the <1.0 mL group than in the ≥1.0 mL groups (46.0% [86/187] vs. 67.5%-74.3% [172/255 to 124/167], respectively; p<0.01). Low oolemma stretchability was significantly more common in the <1.0 mL group than in the ≥1.0 mL groups during ICSI (22.0% [13/59] vs. 5.8%-9.4% [6/104 to 13/139], respectively; p=0.018). There was a relationship between FF volume and oolemma stretchability. However, there were no significant differences in the rates of fertilization, cleavage, ≥7 cells at day 3, and blastocyst development among all groups. CONCLUSION: FF volume is potentially associated with the stretchability of metaphase II oolemma during ICSI. Regarding oolemma stretchability, ensuring a uniform follicular size during ovarian stimulation is crucial to obtain good-quality oocytes.