Impact of multinucleated blastomeres on embryo developmental competence, morphokinetics, and aneuploidy

Blastomere multinucleation occurs equally in both euploid and aneuploid human embryos. Most of the multinucleated embryos have the capability to self-correct during early cleavage divisions and can implant and develop into healthy babies.

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Volume 106, Issue 3, Pages 608-614

Authors:

Hanna Balakier, Ph.D., Agata Sojecki, M.Sc., Gelareh Motamedi, M.Sc., Clifford Librach, M.D.

Abstract:

Objective

To study the effect of human embryo multinucleation on the rate of aneuploidy, in vitro developmental morphokinetics, and pregnancy outcome.

Design

Retrospective study.

Setting

University-affiliated fertility center.

Patient(s)

A total of 296 patients undergoing IVF cycles.

Intervention(s)

None.

Main Outcome Measure(s)

Rate of multinucleation at the 2- and 4-cell stage, time-lapse morphokinetic parameters from zygote to blastocyst stage, ploidy of embryos analyzed by means of trophectoderm biopsy and array comparative genomic hybridization (PGS), and pregnancy outcome.

Result(s)

A total of 1,055 out of 2,441 (43.2%) embryos evaluated with the use of the Embryoscope time-lapse system showed blastomere multinucleation at the 2-cell stage (MN2). The frequency of this abnormality was substantially reduced in 4-cell-embryos (15.0%). Among all clinical factors analyzed, only maternal age had a positive correlation with multinucleation rate. The timing of cleavage divisions from the pronuclear fading to 5-cell embryo was significantly longer (1.0–2.5 h) in MN2 embryos than in non-MN2 control samples. Of the total embryos tested with the use of PGS (n = 607), the rates of multinucleation were similar in euploid versus aneuploid blastocysts (40.8% and 46.7%, respectively). All 24 chromosomes contributed to aneuploidy of MN2 embryos. There were 61 transfers of MN2 embryos that resulted in 45.9% clinical pregnancies and a 31.6% implantation rate.

Conclusion(s)

The frequency of multinucleation is high in human embryos cultured in vitro and equally affects euploid and aneuploid human embryos. It appears that most MN embryos have the capacity for self-correction during early cleavage divisions and can develop into euploid blastocysts resulting in healthy babies.


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Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility® is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders. The journal publishes juried original scientific articles in clinical and laboratory research relevant to reproductive endocrinology, urology, andrology, physiology, immunology, genetics, contraception, and menopause. Fertility and Sterility® encourages and supports meaningful basic and clinical research, and facilitates and promotes excellence in professional education, in the field of reproductive medicine.

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