Cryptic sperm defects may be the cause for total fertilization failure in oocyte donor cycles

Abstract

In conventional IVF cycles with total fertilization failure, rescue intracytoplasmic sperm injection (ICSI) performed 24h after insemination has yielded poor results. However, when ICSI is used, total fertilization failure is a rare event. The aim of the present study is to investigate the degree of sperm contribution to fertilization failures using the egg-sharing model in oocyte donor cycles. The study included only the oocyte donor cycles of sibling oocytes with total fertilization failure in at least one of the matched recipients. Oocytes from 49 oocyte donor cycles were equally shared among 98 recipients undergoing conventional IVF. Due to total fertilization failure in half of the recipients, rescue ICSI was carried out. Compared with the conventional IVF only group, the rescue ICSI group had a lower pregnancy rate (30.61% versus 71.43%), clinical pregnancy rate (28.57% versus 67.35%) and ongoing pregnancy rate (28.57% versus 63.27%) (all P<0.01). Cryptic sperm defects in apparently normal spermatozoa may be the cause of total fertilization failure, indicating the need for simple routine tests to detect them.

Total fertilization failure: is it the end of the story?

“…Successful fertilization depends on cytoplasmic as well as nuclear maturation of the oocytes. Although these are the crucial steps for oocytes to obtain the ability to respond to signals from spermatozoa at the time of fertilization, oocyte maturity cannot be assessed with classical IVF techniques [11]. Maturity of oocytes is usually inferred from follicular size, however it is not an absolute relation [9].…”

Association between etiologic factors in infertile couples and fertilization failure in conventional in vitro fertilization cycles

“…Predicting and minimizing the risk of TFF would be the best resolution for it. However, it is difficult to predict low fertilization (fertilization rate < 20%) or even total FF in IVF cycles due to various influencing factors such as improper ovarian stimulation protocol, known or unknown defects of the oocyte and/or the spermatozoon (Benadiva et al ., ; Chen & Kattera, ; Mannikko et al ., ; Gasca et al ., ; Rawe et al ., ; Goudakou et al ., ). For all this, the etiopathogenesis of FF and the rescue approach are still under research (van der Westerlaken et al ., ; Kinzer et al ., ; Tanahatoe et al ., ; Terada et al ., ; Moon et al ., ).…”

Increased pregnancy after reduced male abstinence

“…While high resolution microscopy for selection of better sperm morphology [Bartoov et al 2003;Antinori et al 2008] and hyaluronic acid based diluents for the best physiological conditions [Huzar et al 2003] allow indirect selection of the most capable sperm along with the quality DNA, treatments such as the use of the magnetic beads can potentially lead to compromises in physiological homeostasis of the sperm cell [Salian et al 2012]. This may well produce cryptic levels of iatrogenic sperm damage that could compromise the reproductive outcome [Goudakou et al 2012].…”