A formula for scoring human embryo growth rates in in vitro fertilization: Its value in predicting pregnancy and in comparison with visual estimates of embryo quality

Abstract

Two systems for measuring embryo development in vitro were evaluated. One was a 1-4 scale based on a subjective evaluation of embryo quality (EQ) from microscopic appearance. In addition, a formula for scoring embryo growth rate in vitro was developed. The embryo development rating (EDR) was based on the ratio between the time at which embryos were observed at a particular stage after insemination and the time at which they would be expected to reach that stage in a hypothetical "ideal" growth rate with a cell cycle length of 11.9 hr. Using this scoring system, "normally" growing embryos scored 100. This approach was aimed at partially normalizing the data and allowed all embryos to be analyzed similarly regardless of the time of observation. Analysis of 1539 embryo replacements resulting in 232 clinical pregnancies showed that both EDR and embryo-quality scores were of value in predicting success, with clinical pregnancy most likely to eventuate from a combination of moderate to good EQ scores (2-4) coupled with average or above-average growth rates (EDR scores from 90 to 129). Poor-quality and very slowly or very rapidly growing embryos were underrepresented in cycles that proceeded to pregnancy. These inferences were based on all embryos transferred (mean, 2.73 per transfer cycle), and they were substantiated by an analysis of 33 pregnancies resulting from replacement of a single embryo and from 18 pregnancies in which all embryos scored the same with both systems. EQ and EDR were significantly associated with each other and together provide a valuable guide in predicting pregnancy, in selecting embryos for freezing, and in monitoring day-to-day performance in the in vitro fertilization (IVF) program.

Human Embryonic Behavior Observed with Time-Lapse Cinematography

“…NPBs are therefore likely to play important biological roles in early embryonic development. Several studies have correlated NPBs with embryo quality [12][13][14]. However, our TLC analysis revealed the distributions of NPBs to be quite dynamic with polarity changes from time to time, which made it extremly difficult to predict embryo quality based on NPBs in a single observation.…”

An oocyte score for use in assisted reproduction

“…This is usually achieved either by the extended culture of human embryos to the blastocyst stage [5,6] or by the morphological analysis and selection of the highest quality embryos for transfer [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. More recently, the assessment of zygote quality has been applied [23][24][25][26][27][28][29][30][31][32].…”

Conventional IVF versus ICSI in sibling oocytes from couples with endometriosis and normozoospermic semen

“…The embryos were evaluated 24 h later (42 h after insemination or injection) by another embryologist. Embryo classification was modified from the system described by Cummins et al [22]. Grade 1 embryos consisted of symmetrical blastomeres of without anucleated fragments.…”