PurposeEmbryo kinetics analysis is an emerging tool for selecting embryo(s) for transfer. The aim of the present study was to determine morphokinetic parameters easily usable in the laboratory and predictive of embryo development and, most importantly, of embryo competence in producing a clinical pregnancy after day 5 transfer.MethodsA retrospective time-lapse monitoring analysis of morphokinetic parameters for 72 fully implanted embryos (group A) were compared to 106 non-implanted embryos (group B), and to 66 embryos with arrested development from the same pool of group A. All the embryos were from 78 patients undergoing ICSI treatment and day 5 embryo transfers.ResultsA day 3 embryo will develop into a viable blastocyst if the following ranges of morphokinetic parameters are met: t1 (between 18.4 h and 30.9 h post-ICSI), t2 (21.4–34.8 h), t4 (33.1–57.2 h), t7 (46.1–82.5 h), t8 (46.4–97.8 h), tC-tF (7.7–22.9 h) and s3 (0.7–30.8 h). On day 5 embryos with the highest probability to implant are those with a cc3 between 9.7 h and 21 h.ConclusionsMorphokinetic parameters are helpful to make appropriate decisions for the disposition of each embryo. It is recommended that each laboratory should determine its own ranges of in vitro development (IVD-MKP) and implantation-associated (IMP-MKP) morphokinetic parameters.

With a view to correlating oocyte morphology and meiotic spindle presence to clinical intracytoplasmic sperm injection (ICSI) outcomes, 967 oocytes that led to 967 transferred embryos in 404 embryo transfers were studied. No relationship was found between oocyte morphology (ooplasm texture, perivitelline space largeness, perivitelline space granulation absence/presence and the first polar body shape) or meiotic spindle presence or absence and clinical pregnancy per transfer and implantation rates after ICSI. It was concluded that oocyte morphology and meiotic spindle presence or absence can only predict fertilization, cleavage rates and embryo quality, as previously described in the literature, but do not help in daily ICSI practice in the choice of the metaphase II oocyte that will lead to the embryo that starts clinical pregnancy.

Partial disruption of the MII spindle and associated chromosomes accompanies inadequate cryopreservation during slow cooling. However, protocols adopting higher sucrose concentration in the freezing solution promote the retention of an intact chromosome segregation apparatus comparable in incidence to freshly collected oocytes.

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In Italy, the restrictive IVF law generalizes the indication for oocyte freezing for surplus oocytes in 78.5% of in-vitro assisted reproductive cycles. With a view to understanding better what the prospects for intracytoplasmic sperm injection (ICSI) on frozen-thawed oocytes might be, the consequences of freeze-thaw procedures on fertilization, cleavage rates and embryo quality obtained from frozen-thawed oocytes were studied and compared with the results obtained from sibling fresh oocytes. Eleven IVF and 29 ICSI on 76 and 169 fresh oocytes were performed and the corresponding 40 ICSI on 221 sibling frozen-thawed oocytes. There was no difference in terms of fertilization rate between fresh and sibling frozen-thawed oocytes. The cleavage rate (98.0 and 94.4% with fresh oocytes in IVF and ICSI; 77.3% with frozen-thawed oocytes in ICSI; P < 0.001) and embryo quality (grade I embryos over total embryos: 36.7 and 22.2% with fresh oocytes in IVF and ICSI; 12.1% with frozen-thawed oocytes in ICSI; respectively P < 0.001 and P < 0.05) were statistically lower after oocyte cryopreservation. The significant decrease in meiotic spindle retrieval rate before freezing (62.4%) and after thawing procedures (43.4%; P < 0.001) suggests that cryoconservation induces irreversible damage to microtubule repolymerization. The consequences of oocyte cryopreservation procedures on embryo development are reviewed.