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Improved Embryo Selection in IVF Cycles
A recent study aimed to determine if there are “kinetic differences” (the timing of different divisions in the embryo) that influence an embryo’s potential to to implant in an IVF cycle. Using time-lapse imaging, 648 embryos transferred on day 5 were analyzed. “The complete history of the embryo, rather than static observations once a day offers a unique insight in to the embryos’ potential,” says Dr. Nina Desai, IVF Lab Director at Cleveland Clinic Fertility Center, and lead author of the study. “Our job as embryologists is to critically examine the large amount of data now available through time lapse and to find the parameters most often associated with successful implantation.”
Desai explained “kinetic differences” as follows. Let’s say one embryo divides from two to three cells and then stays at three cells for an extended period of time before completing the division and becoming a four-cell embryo. That is different from an embryo that goes from two to three to four cells in less than an hour. The patterns of division, the rest phase between divisions, and the timings of later events like blastocyst formation can be tracked for each embryo.
“We found significant differences in kinetics between implanting and non-implanting embryos,” Desai said. She was also able to visualize abnormal events during cell division. “Without time-lapse, these events might remain hidden and an embryo with these anomalies could potentially be selected for transfer,” she added.
Time lapse technology continuously monitors embryo development in an undisturbed environment, as opposed to periodic observations of the embryo. This means observations can be made without handling the dishes and even remotely via computer, Desai says. “The data coming from time lapse offers laboratories tremendous opportunities in terms of understanding embryo biology, patient-specific problems in embryonic development and may even prove be a useful tool for comparing different culture media or treatments.”
“Using these observations we designed a formula to help select the best embryo for transfer. We continue to have high implantation rates with this new technology, and it is serving as an impetus to reducing the number of embryos transferred to achieve a pregnancy.”
The study was published in Reproductive Biology and Endocrinology on June 6, 2014.