Evaluation of a New Embryo-Grading System to Predict Pregnancy Rates following in vitro Fertilization

Abstract

This study examines two descriptive parameters of embryo morphology to determine if either parameter correlates with subsequent pregnancy rates (PRs). The two parameters were the evenness (similarity in size) of the blas-tomeres and the degree of cellular fragmentation. A total of 242 embryo transfers in which 4 embryos were transferred were included. Sixty-nine (28.5%) clinical and 62 (25.6%) viable pregnancies resulted. In all cases 4 embryos were transferred, but the number of embryos with even round blastomeres (grade 1) varied from 0 to 4. Statistically, there was no correlation between PR and number of grade 1 embryos transferred. When 4 grade 1 embryos were transferred, the PR was 33.3 versus 28.1% when no grade 1 embryos were transferred. There was, however, a statistical difference in the implantation rate; a higher frequency of multiple gestations occurred when 3 or 4 of the embryos transferred were graded 1:12.7 as compared with 6.7% when < 2 embryos were grade 1. The significance of the degree of cellular fragmentation in the embryos was also assessed. There was no statistical difference in the PR according to the number (0–4) of embryos transferred that did not have fragments (grade A). When 4 grade A embryos were transferred, the PR was 18.2 versus 26.1 % when there were no grade A embryos. Neither implantation nor multiple-birth rates correlated with fragmentation.

A Study to Determine if Certain Sonographic Uterine Parameters Are Associated with Multiple Gestation

“…Previous data from our IVF center failed to show improved pregnancy or implantation rates according to embryo morphology or fragmentation [22]. The study presented herein further demonstrated that less fragmented embryos are not more likely to cause multiple gestations than more fragmented ones.…”

“…Similar conclusions were reached by evaluating symmetry. However, embryo cell number did correlate with higher rates of multiple births suggesting that embryo factors rather than uterine environment has the greatest influence for multiple gestation [22].…”

Chromosomal disorders and nuclear and cell destruction in cleaving human embryos

“…In general, the potential of preimplantation chromosomal testing for selection of most viable embryos (apart from cases with known family problems) remains questionable and this approach is applied in a very limited number of IVF centers (Munne, 2003). In most fertility clinics, like ten years earlier, the selection of replaced embryos is based on their morphology , Giorgetti et al, 1995, Hoover et al, 1995. In our IVF center the practice is the same.…”

Zona pellucida thickness variation and occurrence of visible mononucleated blastomeres in preembryos are associated with a high pregnancy rate in IVF treatment

“…Thus, based on the present results, it is not possible to rank the importance of EDR or fragmentation compared to ZPTV of VMBs, although the latter characteristics had the ability of further prediction. EDR has been found to have some value in .assessing preembryo quality (18,19), while the role of fragmentation has been questioned (20). Nevertheless, a high rate of fragmentation seemed to impair embryo viability and correlated with a high rate of chromosomal aberrations (21).…”