The clinical use of time-lapse in human-assisted reproduction

Abstract

A major challenge in the assisted reproduction laboratory is to set up reproducible and efficient criteria to identify the embryo with the highest developmental potential. Over the years, several methods have been used worldwide with this purpose. Initially, standard morphology assessment was the only available strategy. It is now universally recognized that besides being a very subjective embryo selection strategy, morphology evaluation alone has a very poor prognostic value. More recently, the availability of time-lapse incubators allowed a continuous monitoring of human embryo development. This technology has spread quickly and many fertility clinics over the world produced a remarkable amount of data. To date, however, a general consensus on which variables, or combination of variables, should play a central role in embryo selection is still lacking. Many confounding factors, concerning both patient features and clinical and biological procedures, have been observed to influence embryo development. In addition, several studies have reported unexpected positive outcomes, even in the presence of abnormal developmental criteria. While it does not seem that time-lapse technology is ready to entirely replace the more invasive preimplantation genetic testing in identifying the embryo with the highest implantation potential, it is certainly true that its application is rapidly growing, becoming progressively more accurate. Studies involving artificial intelligence and deep-learning models as well as combining morphokinetic with other non-invasive markers of embryo development, are currently ongoing, raising hopes for its successful applicability for clinical purpose in the near future. The present review mainly focuses on data published starting from the first decade of 2000, when time-lapse technology was introduced as a routine clinical practice in the infertility centers.

Zygote Diameter and Total Cytoplasmic Volume as Useful Predictive Tools of Blastocyst Quality

“…The tPNf was shorter for embryos that developed into good-quality blastocysts in this study, in line with previously published data 2 6 26 27 28 . A few studies conducted with sizable datasets have confirmed that the choice of culture medium does not affect PN fading 29 30 31 .…”

“…A few studies conducted with sizable datasets have confirmed that the choice of culture medium does not affect PN fading 29 30 31 . What is more, obtained results about the impact of tPNf on blastocyst quality were in line with previously published results 27 28 .…”

“…On average, the tPNf was shorter for embryos that reached the blastocyst stage than for those that failed (22.00 [17][18][19][20][21][22][23][24][25][26][27][28][29] vs. 23.00 h, p < 0.01; ▶ Table 1). Moreover, good-quality blastocysts were developed from embryos with shorter time frame of tPNf ( 21.00 [17][18][19][20][21][22][23][24][25][26][27][28] vs. 23.00 [18][19][20][21][22][23][24][25][26][27][28][29] h, p < 0.0001; ▶ Fig. 4).…”

Case Report: Post-Partum SARS-CoV-2 Infection After the First French Uterus Transplantation

“…However, 29 (85%) showed abnormal developmental kinetics or abnormal developmental phenotypes by time-lapse imaging, despite being suitable for cryopreservation. These abnormalities have been associated with decreased implantation potential ( 7 ). We therefore proceeded with a second IVF cycle, from which 44 oocytes were retrieved and 23 blastocysts were frozen; 18 (78%) showed abnormal kinetics and/or abnormalities.…”

Non-invasive evaluation of embryo quality for the selection of transferable embryos in human in vitro fertilization-embryo transfer

“…The quality of blastocysts is also assessed according to the blastocysts' expansion state and the appearance of the inner cell mass (ICM) and trophectoderm cells (TE) [12]. Transferable embryos are traditionally selected through a time-point observation of morphological features by trained clinical embryologists with expertise in embryo evaluation [13]. However, there are some limits in accurately predicting the developmental capacity of embryos by microscopic observations.…”