Spindle imaging: a marker for embryo development and implantation.
OBJECTIVE
To examine whether the presence of birefringent spindles in living human oocytes can be used as a predictive factor associated with embryo morphology to allow embryo selection before transfer and its association with IVF outcomes.


METHODS
Prospective study.


METHODS
Assisted reproduction center in Brazil.


METHODS
One hundred fifty-seven patients undergoing intracytoplasmic sperm injection cycles, resulting in 1,097 metaphase II oocytes.


METHODS
Meiotic spindles were evaluated before intracytoplasmic sperm injection in all metaphase II oocytes.


METHODS
Meiotic spindles' imaging and fertilization rate, embryo development, and implantation rate.


RESULTS
Birefringent spindles were detected in 65.9% (SD group). The normal fertilization rate and rate of early-cleavaged embryos were higher in the SD group compared with in the spindle-non-detected (SND) group. When only embryos from the SD group were selected for transfer, the pregnancy and implantation rates were 44.4% and 23.0%, and when only embryos from the SND group were transferred, those rates were 18.2% and 8.7%, respectively (statistically significant differences).


CONCLUSIONS
Spindle visualization can be an important tool for predicting better fertilization potential, embryo development, and clinical outcomes, suggesting that embryo selection for transfer may be based not only on embryo morphology but also on oocyte nuclear maturity.
Madaschi
Camila
C
Fertility-Assisted Fertilization Center, São Paulo, Brazil.
de Souza Bonetti
Tatiana Carvalho
TC
de Almeida Ferreira Braga
Daniela Paes
DP
Pasqualotto
Fabio Firmbach
FF
Iaconelli
Assumpto
A
Borges
Edson
E
D000328:Adult; D001718:Birefringence; D001938:Brazil; D010064:Embryo Implantation; D004624:Embryo Transfer; D047108:Embryonic Development; D005260:Female; D006801:Humans; D007246:Infertility / Q000628:therapy*; D008540:Meiosis; D008859:Microscopy, Polarization; D054315:Oocyte Retrieval; D009865:Oocytes / Q000254:growth & development / Q000648:ultrastructure*; D011247:Pregnancy; D011446:Prospective Studies; D020554:Sperm Injections, Intracytoplasmic; D008941:Spindle Apparatus / Q000648:ultrastructure*; D016896:Treatment Outcome