Effects of cumulus cells removal after 6 h co-incubation of gametes on the outcomes of human IVF

Abstract

The present results indicate that cumulus cells removal at 6 h of insemination is a relatively safe operation, which yielded comparable normal fertilization rate, multinucleation and clinical pregnancy rates compared with 20 h group. This protocol may be beneficial for early obsevation of fertilization failure and make early rescue ICSI possible.

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

“…This result supports the previous data [1,21] but is inconsistent with another report by Wei et al [19], which have shown a decrease in the quantity of available embryo rate. The different study designs could explain these conflicting results.…”

“…In a study by Chen and Kattera [1], tripronuclear Patients with fertilization failure were not included rate was 6.1 % was obtained. 7.5 % polyspermy rate was observed by Xiong et al [21]. It should be noted that the cumulus cells were removed at 6 h of insemination in the latter two studies.…”

“…In a limited number of studies, there are conflicting data regarding the effect of early cumulus cell removal on fertilization and embryo quality. Wei et al [19] reported a significant reduction in the rate of available embryo after cumulus cell removal 4 h postinsemination, while others have described an equivalent embryo morphology compared with cumulus cell removal between 18 and 22 h post-insemination [1,21]. The polyspermy rate in case of early cumulus cell removal was usually unchanged except as reported by Xiong et al [21], which has described a decreased polyspermy rate.…”

“…Rescue of 1-day-old oocytes by intracytoplasmic sperm injection (ICSI) that have failed to fertilize usually results in very poor clinical outcomes [5, 6, 8, 9, 11-13, 15, 16]. In order to reduce the proportion of failed fertilization cycles, a treatment observing early signs of fertilization after a short time of gamete coincubation has been used in IVF cycles [1,10,19,21]. Those in which the second polar body (2 PB) has extruded are considered to be fertilized.…”

Determining the need for rescue intracytoplasmic sperm injection in partial fertilisation failure during a conventional IVF cycle

“…If fertilisation failure is caused when binding of the spermatozoon to the zona pellucida, rescue ICSI may work; however, if the spermatozoon can penetrate the ovum successfully, but encounter difficulties in the subsequent oocyte activation and pronucleus formation, rescue ICSI will be ineffective. To determine the need for rescue ICSI based on the extrusion of 2PB 4-6 h after insemination has become a widely recognised approach (Chen & Kattera, 2003;Xiong et al, 2011;Zhu et al, 2011a,b). At 4-6 h after fertilisation, the extrusion rate of 2PB ranges from 78 to 86% ( Van den Bergh et al, 1995;Suppinyopong et al, 2000;Jin et al, 2014).…”