Correlation between morphokinetic parameters and standard morphological assessment: what can we predict from early embryo development? A time-lapse-based experiment with 2085 blastocysts.

OBJECTIVES: To evaluate the association between morphology grading and morphokinetic parameters in blastocyst stage embryos cultured in a time-lapse system. METHODS: This retrospective cohort study included patients offered fertility treatment with autologous oocytes in our clinic between October 2017 and May 2019 using a time-lapse system. The embryos were morphologically graded according to the criteria developed by Gardner and Schoolcraft and their morphokinetic parameters were recorded. RESULTS: Our results indicated that the time of pronuclei fading (tPNf), time to cleavage into two (t2), four (t4), and eight (t8) cells, and time to start of blastulation (tB) were significantly different according to the morphological quality of the blastocysts formed. In the early development stage, tPNf, t2 and t4 differed between good (AA, AB, BA, BB) and poor (CC) quality potential blastocysts. The 8-cell stage time separated embryos graded as AA blastocysts in terms of morphology from embryos graded as BB. Earlier tB correlated with higher quality embryos (AA, AB, BA). CONCLUSION: Our results showed that the first kinetic parameters (tPNf, t2, and t4) distinguished top-graded from low-graded blastocysts. Between top-graded blastocysts, t8 separated BB blastocysts from AA blastocysts. And finally, tB also told apart BB blastocysts from AA, AB, and BA blastocysts. These time-related parameters may be applied even in centers without time-lapse systems.

Egg donation of vitrified oocytes bank produces similar pregnancy rates by blastocyst transfer when compared to fresh cycle.

PURPOSE: Advances in reproductive techniques, mainly the introduction of oocyte vitrification, have provided the opportunity to conceive from oocyte banks. The aim of this study was to compare the clinical outcomes of fresh and vitrified oocytes in an egg donation program following blastocyst transfer. METHODS: This retrospective observational study included 504 oocyte donation cycles. All donor women were younger than 30 years of age. The recipient cycles were divided into two groups: fresh oocytes (n = 78) or vitrified oocytes (n = 426). All oocytes were fertilized by ICSI using ejaculated sperm, followed by blastocyst transfer. Endometrium preparation was performed with estradiol valerate plus micronized progesterone according to standard protocols. RESULTS: Recipients were of similar age (fresh 42.0 ± 4.5 years vs vitrified 41.8 ± 4.8 years; p = 0.790). The fresh group received more mature oocytes for injection compared to the vitrified group (10.1 ± 2.8 vs 9.2 ± 2.2; p = 0.005). The two pronuclei (2PN) rate (74.5 vs 77.4%; p = 0.195) and blastocyst rate (48.8 vs 51.6%; 0.329) were similar between the fresh and vitrified groups, respectively. The rates of clinical pregnancy were 60.9% in the fresh and 59.0% in the vitrified groups (p = 0.771). CONCLUSIONS: Our findings suggest that vitrified oocytes result in similar pregnancy rates when compared to fresh oocytes with blastocyst transfer in an egg donation program. Moreover, vitrified oocytes may allow for a better cycle schedule, starting with a lower number of oocytes to be fertilized. Therefore, we hypothesize that egg banks with vitrified oocytes could be safely utilized in an egg donation program.

Does slow embryo development predict a high aneuploidy rate on trophectoderm biopsy?

The aneuploidy rates in expanded blastocysts biopsied on days 5 and 6 development were assessed in women undergoing IVF followed by array comparative genomic hybridization. This study included 1171 expanded blastocysts from 465 patients. Among the 465 patients, 215 and 141 underwent embryo biopsy on day 5 and day 6 (46.2% and 30.3%, respectively), and 109 underwent biopsy on both days 5 and 6 (23.4%). The cycles of 206 women were cancelled because only aneuploidy embryos were present (44.3%). The aneuploid embryos were classified according to the type as single, double or complex aneuploidy. No differences were observed in the distributions of these three categories according to the day of the biopsy. The aneuploidy rate was also evaluated according to maternal age, and was found to be higher in older patients; however, no differences in this rate were detected between embryos biopsied on days 5 and 6 according to maternal age. Biopsy was carried out when blastocysts reached the expanded stage. The embryos biopsied on day 6 had a higher rate of aneuploidy (69.9%) than those biopsied on day 5 (61.4%); however, the euploid embryos transferred had similar chances for successful and healthy gestation.