P-290 Choosing the appropriate fertilization method would increase fertilization rate and improve embryo quality
Authors: Shibli Y , Raya Abu , Bilgory A , Atzmon Y , Aslih N , Shavit M , Sharqawi M , Michaeli M , Rotfarb N , Polotov D , Harush C , Shalom-Paz E 
Published: June 2023

Abstract

Study question
The impact of Conventional IVF versus ICSI on embryo morphokinetic is still scarce. Would proper selection of fertilization method affect embryonic development in different subgroups?

Summary answer
In unexplained or tubal factor subgruops, convential IVF was preferable resulting in higher fertilization rate and better embryo quality expressed by less discarded embryos.

What is known already
IVF requires a sperm cell to penetrate the cumulus cells and the zona pellucida, but ICSI can induce insemination without certain processes taking place. Moreover, ICSI is more invasive than conventional IVF. For example, ICSI oocytes are exposed to hyaluronidase and intense light during the denuding process and are damaged by mechanical pipetting. It was found that ICSI-fertilized 4-cell embryos spent approximately 2.5 hours less time in the 2-cell stage than IVF-fertilized 4-cell embryos, and that the 3-cell stage was longer in ICSI-fertilized oocytes. In addition, the first cleavage has been reported to be slow in conventional IVF.

Study design, size, duration
A retrospective analysis of prospective collective data of all fresh ART (assisted reproductive technique) cycles, conducted and underwent in a single IVF clinic center.

Participants/materials, setting, methods
The study collected a total of 11472 fertilized oocytes that were studied using a time-lapse system (Embryoscope). A total of 2085 oocytes were fertilized by insemination (conventional IVF group) and 9387 were fertilized by ICSI (ICSI group). All oocytes in the study were sibling oocytes. All embryos were investigated for the developmental events.

Main results and the role of chance
Significantly Younger maternal age (34.6 vs. 34.1; P &lt; 0.001) and more male factor infertility (43% vs. 14%; P &lt; 0.001) were in the ICSI group. Normal fertilization (2PN) was significantly more in the conventional IVF (98% vs. 89.9%). Significantly more embryos were transferred and discarded (37% vs 33%; P &lt; 0.001( in the ICSI group and more frozen in the conventional IVF group 59% vs. 46.5%; P &lt; 0.001).
In the ICSI group all parameters of fertilization and morphokinetics starting in the time to pronuclear appearance till time to morula stage were significantly shorter. KID score was comparable between the groups for all transferred and frozen embryos (3.23 vs 3.3 P = 0.08), however, significantly more embryos were discarded in the ICSI group (16.5% vs 8% p &lt; 0.001).

Limitations, reasons for caution
This is a retrospective study. We can’t report our cumulative pregnancy rate since not all frozen embryos were transferred yet.

Wider implications of the findings
Regardless of male factor, given the debate between IVF vs ICSI techniques in daily IVF cycles, our results spotlight the better results of conventional IVF for anovulation, unexplained infertility and tubal factor and enable us to offer a personalized treatment.

Trial registration number
Trial registration number number is 026-20-HWMC