Can Time-Lapse Incubation and Monitoring Be Beneficial to Assisted Reproduction Technology Outcomes? A Randomized Controlled Trial Using Day 3 Double Embryo Transfer

We report studies of preimplantation human embryo development that correlate time-lapse image analysis and gene expression profiling. By examining a large set of zygotes from in vitro fertilization (IVF), we find that success in progression to the blastocyst stage can be predicted with >93% sensitivity and specificity by measuring three dynamic, noninvasive imaging parameters by day 2 after fertilization, before embryonic genome activation (EGA). These parameters can be reliably monitored by automated image analysis, confirming that successful development follows a set of carefully orchestrated and predictable events. Moreover, we show that imaging phenotypes reflect molecular programs of the embryo and of individual blastomeres. Single-cell gene expression analysis reveals that blastomeres develop cell autonomously, with some cells advancing to EGA and others arresting. These studies indicate that success and failure in human embryo development is largely determined before EGA. Our methods and algorithms may provide an approach for early diagnosis of embryo potential in assisted reproduction.

Time-lapse observation presents an opportunity for optimizing embryo selection based on morphological grading as well as providing novel kinetic parameters, which may further improve accurate selection of viable embryos. The objective of this retrospective study was to identify the morphokinetic parameters specific to embryos that were capable of implanting. In order to compare a large number of embryos, with minimal variation in culture conditions, we have used an automatic embryo monitoring system. Using a tri-gas IVF incubator with a built-in camera designed to automatically acquire images at defined time points, we have simultaneously monitored up to 72 individual embryos without removing the embryos from the controlled environment. Images were acquired every 15 min in five different focal planes for at least 64 h for each embryo. We have monitored the development of transferred embryos from 285 couples undergoing their first ICSI cycle. The total number of transferred embryos was 522, of which 247 either failed to implant or fully implanted, with full implantation meaning that all transferred embryos in a treatment implanted. A detailed retrospective analysis of cleavage times, blastomere size and multinucleation was made for the 247 transferred embryos with either failed or full implantation. We found that several parameters were significantly correlated with subsequent implantation (e.g. time of first and subsequent cleavages as well as the time between cleavages). The most predictive parameters were: (i) time of division to 5 cells, t5 (48.8-56.6 h after ICSI); (ii) time between division to 3 cells and subsequent division to 4 cells, s2 (≤ 0.76 h) and (iii) duration of cell cycle two, i.e. time between division to 2 cells and division to 3 cells, cc2 (≤ 11.9 h). We also observed aberrant behavior such as multinucleation at the 4 cell stage, uneven blastomere size at the 2 cell stage and abrupt cell division to three or more cells, which appeared to largely preclude implantation. The image acquisition and time-lapse analysis system makes it possible to determine exact timing of embryo cleavages in a clinical setting. We propose a multivariable model based on our findings to classify embryos according to their probability of implantation. The efficacy of this classification will be evaluated in a prospective randomized study that ultimately will determine if implantation rates can be improved by time-lapse analysis.

To quantify the effect on reproductive outcome of culturing and selecting embryos using a novel time-lapse monitoring system (TMS). Retrospective observational cohort study. University-affiliated private center. Donation and autologous intracytoplasmic sperm injection (ICSI) cycles from ten IVF clinics using similar procedures, cultured in TMS (n = 1,390) or in a standard incubator (SI; n = 5,915). None. Clinical pregnancy rate confirmed by ultrasound in week 7. A logistic regression analysis, which included all significant confounding factors, was used to evaluate the effect of culturing and selecting embryos with the use of TMS. Comparing clinical pregnancy rates per oocyte retrieval with TMS and SI treatments gave a crude effect of odds ratio [OR] 1.190 (95% confidence interval [CI] 1.058-1.337). Oocyte source, maternal age, day of transfer, and number of retrieved oocytes were identified as significant confounding factors. After accounting for confounding factors, the effect of TMS culture was OR 1.201 (95% CI 1.059-1.363). Limiting analysis to treatments with embryo transfer and including number of transferred embryos as a confounding factor likewise gave a significant effect of TMS with OR 1.157 (95% CI 1.018-1.315). Analysis of retrospective data indicated that culturing and selecting embryos by TMS significantly improved the relative probability of clinical pregnancy (+20.1% per oocyte retrieval, +15.7% per embryo transfer). The elevated clinical pregnancy rate was attributed to a combination of stable culture conditions and the use of morphokinetic parameters for embryo selection. Copyright © 2012 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.