Effect of cumulus cell removal 4 h post-insemination on fertilization and embryo quality: a prospective randomized sibling-oocyte study

Abstract

Purpose The study was designed to evaluate whether cumulus cell removal 4 h post-insemination could influence fertilization and embryo quality. Methods The study included 61couples undergoing standard long down regulation protocol from July 2011 to May 2012. Sibling oocytes of each patient were randomly assigned to either the 4 h group or the 20 group. For the 4 h group, cumulus cells were removed 4 h after gamete coincubation; for the 20 group, cumulus cells removal was performed 20 h after insemination. Fertilization rate, embryo quality, pregnancy rate and implantation rate were assessed. Results A total of 801 sibling cumulus-oocyte complexes (COCs) were randomized to the 4 h group (421 COCs) or 20 h group (380 COCs). There was no difference in the two pronuclei, one pronucleus and grade 1-2 embryo rate. Three pronuclei rate was significantly higher in the 4 h group compared to the 20 h group (12.6 % vs. 8.2 %, P=0.041). Comparison of embryo transfer cycles in which either embryos from the 4 h group or 20 h group were transferred did not reveal any statistically significant differences in pregnancy or implantation rates. Conclusion The results of the present study indicate that cumulus cell removal 4 h post-insemination may increase the percentage of tripronuclear zygotes. However, normal fertilization rate, embryo development, clinical pregnancy rate and implantation rates are not influenced by the timing of cumulus cell removal.

Effect of vitrification versus slow freezing of human day 3 embryos on β-hCG levels

“…Patients included in the study were treated by routine controlled ovarian hyperstimulation (COH) as described by Xue et al [12]. Briefly, the ovaries were stimulated with folliclestimulating hormone (FSH) after mid-luteal pituitary downregulation with a gonadotrophin releasing hormone (GnRH) agonist.…”

Effect of Early Cumulus Cell Removal on the Fertilization and Clinical Outcome in Human <i>in Vitro</i> Fertilization

“…Nevertheless, it is unclear whether the mechanical desorption of cumulus cells can affect normal fertilization or embryonic development potential. For example, various studies have demonstrated that early cumulus cells removal could affect fertilization and embryonic development potential, although contradictory findings are reported [2]- [5]. Moreover, their outcome analysis only examined fertilization outcomes, and did not provide data regarding birth outcomes.…”

Comparison of short and long co-incubation time of gametes for in vitro fertilization

“…Zhou and Liu (co-incubation 6 hours) found that implantation rate and clinical pregnancy rate were similar to long co-incubation. [4][5][6][9][10][11][12][13] In contradiction, Barraud-Lange et al, demonstrated that short co-incubation had low numbers of available embryos for transfer. 14 Nevertheless, a meta-analysis indicates that short coincubation has a significant increase in implantation rate and clinical pregnancy rate.…”

“…[9][10][11][12][13] In the short co-incubation and early cumulus cell removal, the patient had a higher premature delivery, twins and low birth weight newborn than long coincubation. 5,[11][12][13] Li et al, pointed out that cumulus cell removal at a different time can alter spindle integrity and impair cell division which results in twins or poor fetal growth. 18 Moreover, inappropriate mechanical stimulation during cumulus cell removal may cause epigenetic change that is related to low birth weight.…”