[Variability in timing of human embryos cleavage monitored by time-lapse system in relation to patient age].

OBJECTIVE

To monitor time variability of early embryo cleavage by continual monitoring system (time-lapse). To evaluate the impact of patient age for the embryonic growth. To compare pregnancy rate of the time-lapse selected embryos with embryos after ordinary/standard cultivation.

DESIGN

Case-control study.

SETTING

Centre of assisted reproduction Sanus, Pardubice; PPCHC s.r.o. Hradec Kralove.

METHODS

Development of 213 embryos from 44 females was monitored by PrimoVision (time-lapse) system with time frequency of recording 1 image in 12 minutes. The data were evaluated in two groups: infertile patients 35 years (group 35) and control 32 years (group 32). From the collected recordings, time of the first (t2) and of the second (t3) cell cleavage and the time interval between t2 and t3 (cc2) were determined. Symmetrical cellular division to even number of daughter cells, early cleavage and the attainment of blastocyst stage have become the major selection criteria for the embryo transfer.

RESULTS

The following average values of studied parameters were found: Group 35: t2 = 27.0 hours, t3 = 38.7 hours, cc2 = 11.7 hours Group 32: t2 = 27.1 hours, t3 = 39.0 hours, cc2 = 11.9 hours, with no significant differences between both groups. Likewise, no significant difference was observed in mean variability of embryo cleavage timing in an individual patient and control: Group 35: t2 = 4.5 hours, t3 = 5.7 hours, Group 32: t2 = 4.5 hours, t3 = 5.1 hours. No relation was observed between the patient age and t2, t3 and cc2 times when evaluated by regression curve (p = 0.60, p = 0.81, p = 0.57). However, embryos of early cleavage have remained in cc2 period significantly shorter period of time compared to embryos of slower cleavage(p = 0.0001). Pregnancy rate at time-lapse selected embryos reached 55.0% while embryos from standard cultivation only 47%.

CONCLUSION

The impact of patient age to the cleavage dynamic has not been proved. Relation between the first cell cleavage time and embryo persistence in this stage (cc2) was observed. We may hence recommend cc2 time as convenient parameter at embryo selection for embryo transfer in the centres of assisted reproduction. Our study has shown that embryo selection with time-lapse system (PrimoVision) enhances the success rate of treatment of aging patients.