MONDAY, April 17 (HealthDay News) -- Oocytes matured in vitro have more defects in meiotic spindle and chromosome alignment compared to those matured in vivo, which may explain their reduced potential for use in infertility treatments, according to a report in the April issue of Fertility and Sterility.
Zi-Jiang Chen, M.D., Ph.D., from Shandong University in Jinan, China, and colleagues used confocal microscopy to assess spindle and chromosome configurations of human oocytes, obtained from patients at an in vitro fertility center who had polycystic ovary syndrome.
In vitro maturation of oocytes resulted in partial or total disorganization of meiotic spindle microtubules and less condensed or dispersed chromosomes. Spindle and chromosome abnormalities were apparent in 43.7 percent and 33.3 percent of in vitro-matured oocytes, respectively, compared with 13.6 percent and 9.1 percent for oocytes matured in vivo.
"This result suggests one possible explanation for the reduced developmental potential of oocytes matured in vitro compared with those matured in vivo," the authors write. "This is likely a contributing factor to the overall lower clinical outcomes observed after in vitro maturations and embryo transfer."