title: Prolonged absence of meiotic spindles by birefringence imaging negatively affects normal fertilization and embryo development.
abstract: Meiotic spindle (MS) assembly in human oocytes is a dynamic process that can be visualized by computer-assisted microscopy. At extrusion of the first polar body a spindle bridge is detected until the completion of telophase I and its reformation requires approximately 1h. This study analysed 396 oocytes from 112 cycles for fertilization and cleavage according to MS detection at two examinations, 39 and 41 h post-human chorionic gonadotrophin (HCG). All cycles had at least one injected oocyte lacking a visible MS at intracytoplasmic sperm injection (41 h post-HCG). To evaluate the results, oocytes were divided according to the presence (group A) or absence at both observations (group B) of the MS. Compared with group A, group B oocytes had lower normal fertilization rates, higher incidence of three pronuclei and two pronuclei in early dissolution and lower development to blastocyst. Some group A oocytes showed a late MS formation (not visualized at 39 h but at 41 h) and their performance was similar to that of the oocytes with a MS visible at both time points. Although some implantations occurred in group B, these findings suggest that prolonged MS non-detection could be a marker of reduced oocyte competence.
authors: S.I.S.Me.R., Reproductive Medicine Unit, Via Mazzini 12, 40138 Bologna, Italy.
authors: M
authors: M
authors: Cristina Magli
authors: Alessandra
authors: A
authors: Capoti
authors: Silvia
authors: S
authors: Resta
authors: Ilaria
authors: I
authors: Stanghellini
authors: Anna P
authors: AP
authors: Ferraretti
authors: Luca
authors: L
authors: Gianaroli
mesh_terms: D000328:Adult; D001718:Birefringence; D004624:Embryo Transfer; D047108:Embryonic Development; D005260:Female; D005306:Fertilization / Q000502:physiology*; D006801:Humans; D008297:Male; D009865:Oocytes / Q000648:ultrastructure*; D011247:Pregnancy; D018873:Pregnancy Rate; D008941:Spindle Apparatus / Q000648:ultrastructure*