Morphokinetics of human blastocyst expansion in vitro.
Time-lapse imaging offers new tools to study dynamic processes of development such as blastocyst formation and expansion. This study quantitatively describes expansion in human blastocysts from donated oocytes. Measurements of hourly interval rate of changes in the blastocoel cross-sectional area revealed oscillatory pulses having 2-4 h periodicities. Two types of oscillations were distinguished. An E-Type ('expansion') had positive peak and positive or slightly negative trough interval rate of change values, and these characterized most of the expansion period. A C-type ('contraction') represented an infrequent but notable contraction of the blastocoel with loss of blastocoel fluid. These were reversible within 2-4 h in both groups and followed by further expansion. Therefore, oscillatory pulses are an intrinsic property of the trophectoderm. The zona seems to variably dampen the amplitude of these pulses. Expansion kinetics were compared between blastocysts with known positive (KID+) or negative (KID-) implantation outcomes. Regression analysis suggests that expansion may be relatively restricted in KID- embryos blastulating at relatively later times. These data extend observations in other mammalian systems and may provide information useful for clinical selection algorithms.
Department of Obstetrics and Gynecology and Women's Health, John A. Burns School of Medicine, Honolulu, Hawaii, USA; Pacific In Vitro Fertilization Institute, Kapiolani Medical Center for Women and Children, Honolulu, Hawaii, USA. Electronic address: huangt@hawaii.edu.
T T F
TT
Huang
Pacific In Vitro Fertilization Institute, Kapiolani Medical Center for Women and Children, Honolulu, Hawaii, USA.
K
K
Chinn
Department of Obstetrics and Gynecology and Women's Health, John A. Burns School of Medicine, Honolulu, Hawaii, USA; Pacific In Vitro Fertilization Institute, Kapiolani Medical Center for Women and Children, Honolulu, Hawaii, USA.
T
T
Kosasa
Office of Biostatistics and Quantiative Health Sciences, University of Hawaii John A. Burns School of Medicine, Honolulu, Hawaii, USA.
H J
HJ
Ahn
Department of Obstetrics and Gynecology and Women's Health, John A. Burns School of Medicine, Honolulu, Hawaii, USA; Pacific In Vitro Fertilization Institute, Kapiolani Medical Center for Women and Children, Honolulu, Hawaii, USA.
B
B
Kessel
D000328:Adult; D000465:Algorithms; D001755:Blastocyst / Q000502:physiology*; D046149:Embryo Culture Techniques; D010064:Embryo Implantation; D004624:Embryo Transfer; D047108:Embryonic Development; D005260:Female; D006801:Humans; D007700:Kinetics; D009865:Oocytes / Q000166:cytology; D012044:Regression Analysis; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic; D059008:Time-Lapse Imaging; D055815:Young Adult
blastocyst expansion; embryo selection; embryoscope; morphokinetic; time-lapse