Time-Lapse Imaging Reveals Delayed Development of Embryos Carrying Unbalanced Chromosomal Translocation - AWARD NOMINEE

Introduction: Carriers of balanced chromosomal translocations are known to be at risk for reproductive difficulties, repeated miscarriages and birth defects, and PGD is their preferred reproductive treatment. Recent publications show associations between aneuploidy and delayed development as shown by postponed timing of the embryos` morphokinetic parameters. However, time-lapse analysis of embryos carrying chromosomal translocations was not yet examined.

Aim: To compare the morphokinetic parameters of embryos with balanced vs. unbalanced chromosomal translocations, using a time‑lapse microscopy.

Methods: This retrospective cohort study includes all embryos that underwent PGD-FISH for chromosomal translocations in our unit between 04.2013-12.2015 (270 embryos). All these embryos underwent blastomere biopsy at day 3 and morphological and morphkinetic parameters were analyzed on days 1-5 to compare balanced and unbalanced embryos, viable and unviable variants and parental inheritance using time-lapse technology.

Results: Of the 270 biopsied embryos, 23% carry balanced translocations and 77% unbalanced translocations. Interestingly, our results show for the first time that embryos carrying unbalanced translocations demonstrated significantly delayed start of blastulation (tSB) compared with balanced embryos (p=0.019). In accordance, the rate of good-quality blastocysts (determined by Gardner’s scoring) was significantly lower in unbalanced embryos (p=0.004). Moreover, embryos carrying nonviable translocations demonstrated significantly delayed timing of pronuclei fading and tSB compared with viable translocation (p<0.05), and embryos in which the unbalanced translocations was of maternal origin exhibited a significant delay in most of the morphokinetic parameters (p<0.05).

Conclusions: Time-lapse microscopy provides us with a higher resolution in selecting chromosomally balanced embryos than the regular morphological assessment.