SHORT COMMUNICATION: The cumulative embryo score: a predictive embryo scoring technique to select the optimal number of embryos to transfer in an in-vitro fertilization and embryo transfer programme

Abstract

In order to achieve a clinical pregnancy rate higher than that achieved following initial adoption of in-vitro fertilization embryo transfers, more than one embryo is transferred. This has led to a substantial increase in unwanted multiple pregnancy rates with IVF as compared with natural conception. What is therefore required is a simple, clinically useful embryo scoring system, to reflect embryo developmental potential, which will enable the selection of the optimal number of embryos to transfer in order to achieve the maximum pregnancy rate with a low incidence of high order multiple pregnancies. We believe that the Cumulative Embryo Score (CES) achieves these aims. On the day of embryo transfer the grade of each embryo transferred was multiplied by the number of blastomeres to produce a score for each embryo, and summation of the scores obtained for all the embryos transferred gave the CES. The grouped pregnancy rates obtained rose as the CES increased to maximum of 42. A continued increase in the CES above 42 did not result in any further rise in the pregnancy rate. However, an analysis of all our IVF pregnancies showed that the multiple pregnancy rate continued to rise above a CES of 42. By restricting the CES per embryo transfer to 42, 78% of triplet pregnancies and 100% of the quadruplet IVF pregnancies could have been predicted and potentially avoided.

Ovulation triggering with GnRH agonist vs. hCG in the same egg donor population undergoing donor oocyte cycles with GnRH antagonist: a prospective randomized cross-over trial

“…It is unclear, however, if GnRH agonist use results in comparable pregnancy rates. For example, one study found that GnRH agonist use resulted in significantly lower implantation and clinical pregnancy rates, in addition to a significantly higher rate of early pregnancy loss, than observed with hCG, with these differences likely due to luteal phase deficiency [9]. The likelihood of live births was improved after GnRH use in frozenthawed embryo replacement cycles, further suggesting that GnRH agonist triggering is accompanied by luteal phase deficiency [10,11].…”

A randomized clinical trial comparing embryo culture in a conventional incubator with a time-lapse incubator

“…Currently, assessment of embryo morphology remains the choice of method. The correlation between developmental potential and morphological parameters, such as the degree of fragmentation, presence and number of nuclei and size, number and symmetry of blastomeres per embryo at distinct inspection points is well-established [12,31,33,36,39,43]. Present morphological evaluation, however, requires inspection outside the controlled environment of the incubator, which exposes the embryos to undesirable changes in critical parameters: temperature, humidity and pH when evaluated [42].…”

The impact of pronuclear orientation to select chromosomally normal embryos

“…As other groups (6,7,48,49), we have proposed a modified cumulative embryo score (35,50) from PN evaluation until day transfer. Following such criterion the embryo selected to be transferred (top quality embryo) must feature good PN morphology (S0), two cells at 26 h after ICSI, and also be classified as "good quality" on day 3.…”