Day 2 ICSI Leads to the viable pregnancy, when it is a day 1 ICSI?

Abstract

Objective: In about 5% cases of conventional in vitro fertilization (IVF), fertilization fails completely. It can usually be “rescued” by using day 2 intracytoplasmic sperm injection (day 2 ICSI). Day 2 ICSI is still a controversial matter. Some authors report encouraging results, in terms of viable pregnancies; others feel that it should not be done for any purpose other than training. Because day 2 ICSI is often an additional expense for a couple, it would be helpful to have some markers so that patients could be advised for or against day 2 ICSI. We retrospectively analyzed day 2 ICSI cases in an attempt to identify such markers. Design: Twelve cases of day 2 ICSI were retrospectively analyzed using the following criteria: time after human chorionic gonadotropin (hCG), total number of eggs, egg morphology, number of injected eggs, number of fertilized eggs, number of pronuclei, sperm characteristics, embryo quality, number of cells per embryo and number of embryos transferred. Materials/Methods: Oocytes with no pronuclei at 18 hours after an initial insemination were considered unfertilized. They were injected with a spermatozoon within 4 hours thereafter. Fertilization following day 2 ICSI was scored by the presence of pronuclei about 18 hours later. Embryos were scored just prior to the transfer. Morphological appearance of eggs and embryos was documented using b/w film. Results: There was no difference in time after hCG, total number of eggs, fertilization rates, embryo quality, number of cells per embryo or sperm characteristics. At the same time, two cases stood out because of an unusually ratio of 2PN/3PN zygotes, (patient A—4/11 and patient C—4/10) which is an indication of some type of spindle deficiency or a previous sperm penetration without oocyte activation. Both of these phenomena described in immature eggs. The only normal term pregnancy achieved in the entire group was for a patient A. Retrospective analysis of the egg morphology in the case of patient A, revealed that all eggs had a dark center typical for immature or in vitro matured eggs. Conclusions: We speculate that in the case in which pregnancy was achieved, the retrieved eggs were inseminated while immature and subsequently matured in vitro prior to day 2 ICSI. Thus in this case, day 2 ICSI was in effect day 1 ICSI, performed on in vitro matured eggs. If this is true, the couple should be advised to have day 2 ICSI if there is any indication that eggs are immature on the day of retrieval. We further suggest that in cases when there is a reasonable chance to believe that a large proportion of eggs on the day of retrieval will be immature, patients should be suggested to accept ICSI as a first choice regardless of sperm characteristics, because maturation can only be reliably assessed by stripping the cumulus cells from the egg in order to visualize the 1st polar body. Supported by: Department of Obstetrics and Gynecology, Wayne State University, Detroit, Michigan.