Increasing the probability of selecting chromosomally normal embryos by time lapse morphokinetics analysis

Capsule:
A retrospective study demonstrates differences in the kinetics between chromosomally normal and abnormal embryos, providing a selection tool that increases the probability of selecting normal embryos through a noninvasive method.

Authors:
Natalia Basile, Ph.D., María del Carmen Nogales, Ph.D., Fernando Bronet, Ph.D., Mireia Florensa, Ph.D., Marissa Riqueiros, Ph.D., Lorena Rodrigo, Ph.D., Juan García-Velasco, M.D., Marcos Meseguer, Ph.D.

Volume 101, Issue 3, Pages 699-704.e1, March 2014

Abstract:

Objective:
To study the differences in the cleavage time between chromosomally normal and abnormal embryos and to elaborate an algorithm to increase the probability of noninvasively selecting chromosomally normal embryos.

Design:
Retrospective cohort study.

Setting:
University-affiliated infertility center.

Patient(s):
Preimplantation genetic screening patients (n = 125; n = 77 with ET), including cases of repeated implantation failure or recurrent miscarriage. A total of 504 embryos were analyzed.

Intervention(s):
Embryo culture within a time-lapse system.

Main Outcome Measure(s):
Kinetic variables included the time to 2 (t2), 3 (t3), 4 (t4), and 5 (t5) cells as well as the length of the second (cc2 = t3 − t2) and third (cc3 = t5 − t3) cell cycle, the synchrony in the division from 2 to 4 cells (s2 = t4 − t3), and the interval t5 − t2. Implantation and clinical pregnancy rates were also analyzed.

Result(s):
A logistic regression analysis identified t5 − t2 (odds ratio [OR] = 2.853; 95% confidence interval [CI], 1.763–4.616), followed by cc3 (OR = 2.095; 95% CI, 1.356–3.238) as the most relevant variables related to normal chromosomal content. On the basis of these results, an algorithm for embryo selection is proposed to classify embryos from A to D. Each category exhibited significant differences in the percentage of normal embryos (A, 35.9%; B, 26.4%; C, 12.1%; D, 9.8%).

Conclusion(s):
Chromosomally normal and abnormal embryos have different kinetic behavior. On the basis of these differences, the proposed algorithm serves as a tool to classify embryos and to increase the probability of noninvasively selecting normal embryos.

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