Contraction behaviour reduces embryo competence in high-quality euploid blastocysts
The aim of the study is to investigate how blastocyst contraction behaviour affects the reproductive competence in high-quality euploid embryos.
Eight hundred ninety-six high-quality blastocysts derived from 190 patients (mean age 38.05 (SD = 2.9) years) who underwent preimplantation genetic testing for aneuploidies (PGT-A) from January 2016 to October 2017 were included in this study. PGT-A results were reported as euploid or aneuploid. Aneuploid embryos were sub-classified into three categories: monosomy, trisomy and complex aneuploid. Retrospective studies of time-lapse monitoring (TLM) of those embryos were analysed and reproductive outcome of transferred embryos was collected.
A total of 234/896 were euploid (26.1%) whilst 662/896 (73.9%) blastocysts were proven to be aneuploid from which 116 (17.6%) presented monosomies, 136 (20.5%) trisomies and 410 (61.9%) were complex aneuploid. The most frequent chromosomal complements were trisomies affecting chromosome 21 and monosomies involving chromosomes 16 and 22. Data analysis showed a statistical difference in the number of contractions being reported greater in aneuploid when compared to euploid embryos (0.6 vs 1.57; p < 0.001). Analysis of the aneuploid embryos showed that monosomies present less number of contractions when compared to embryos affected with trisomies or complex aneuploidies (1.23 vs 1.53 and 1.40; p < 0.05). No difference was observed when comparing the latter two groups. Euploid embryos presenting at least one contraction resulted in lower implantation and clinical pregnancy rates when compared to blastocysts that do not display this event (47.6 vs 78.5% and 40.0 vs 59.0% respectively).
Most aneuploid blastocysts diagnosed by PGT-A have complex aneuploidies, showing that aneuploid embryos can develop after genomic activation and reaching high morphological scores. It becomes clear that embryo contraction, despite being a physiological feature during blastulation, is conditioned by the ploidy status of the embryo. Furthermore, the presence of contractions may compromise implantation rates.
KeywordsBlastocyst contraction Next-generation sequencing Time-lapse monitoring Preimplantation genetic testing for aneuploidies Ploidy
The authors want to thank Professor Joy Delhanty for her valuable help and expertise revising the final manuscript.
- 1.Aparicio-Ruiz B, Basile N, Perez Albala S, Bronet F, Remohi J, Meseguer M. Automatic time-lapse instrument is superior to single-point morphology observation for selecting viable embryos: retrospective study in oocyte donation. FertilSteril. 2016 Nov;106(6):1379,1385.e10.Google Scholar
- 2.Armstrong S, Arroll N, Cree LM, Jordan V, Farquhar C. Time-lapse systems for embryo incubation and assessment in assisted Reproduction. Cochrane DatabaseSyst Rev. 2015;27(2):CD011320.Google Scholar
- 3.Kirkegaard K, Ahlstrom A, Ingerslev HJ, Hardarson T. Choosing the best embryo by time lapse versus standard morphology. FertilSteril. 2015;103(2):323–32.Google Scholar
- 4.Meseguer M, Rubio I, Cruz M, Basile N, Marcos J, Requena A. Embryo incubation and selection in a time-lapse monitoring system improves pregnancy outcome compared with a standard incubator: a retrospective cohort study. FertilSteril. 2012;98(6):1481,9.e10.Google Scholar
- 5.Fiorentino F, Biricik A, Bono S, Spizzichino L, Cotroneo E, Cottone G, et al. Development and validation of a next-generation sequencing-based protocol for 24-chromosome aneuploidy screening of embryos. FertilSteril. 2014;101(5):1375–82.Google Scholar
- 7.Yang Z, Liu J, Collins GS, Salem SA, Liu X, Lyle SS, et al. Selection of single blastocysts for fresh transfer via standard morphology assessment alone and with array CGH for good prognosis IVF patients: results from a randomized pilot study. MolCytogenet 2012;5(1):24,8166–5-24.Google Scholar
- 9.Wu MY, Chao KH, Chen CD, Chang LJ, Chen SU, Yang YS. Current status of comprehensive chromosome screening for elective single-embryo transfer. ObstetGynecol Int 2014;2014:581783.Google Scholar
- 10.Rienzi L, Capalbo A, Stoppa M, Romano S, Maggiulli R, Albricci L, et al. No evidence of association between blastocyst aneuploidy and morphokinetic assessment in a selected population of poor-prognosis patients: a longitudinal cohort study. Reprod BioMed Online. 2015 Jan;30(1):57–66.CrossRefPubMedGoogle Scholar
- 17.Bodri D, Sugimoto T, Yao Serna J, Kawachiya S, Kato R, Matsumoto T. Blastocyst collapse is not an independent predictor of reduced live birth: a time-lapse study. FertilSteril. 2016;105(6):1476,1483.e3.Google Scholar
- 18.Gardner (2006) In vitro fertilisation: a practical approach. Informa Health, New York. First Edition: pg 212.Google Scholar
- 19.Veek and Zaninovic. An atlas of human blastocysts. Spain: The Parthenon Publishing Group; 2003.Google Scholar
- 22.Stojanov T. The latest product from the Sydney IVF multi-stage media development program. Cook, 2009.Google Scholar
- 31.Esbert M, Marconetto A, Soares SR, Quera M, Molina J, Florensa BA, et al. Does the blastocyst collapse respond to a biological need? The analysis of 1,952 enbryos by time-lapse can give an answer. Unpublished FertilSteril. 2017;108(157)Google Scholar