Randomized study of G-TL and global media for blastocyst culture in the EmbryoScope: morphokinetics, pregnancy, and live births after single-embryo transfer

Morphokinetics of embryo development may vary between media, but this may not always dictate the superiority of one medium over another when looking at pregnancy and live birth outcomes.

VOLUME 114, ISSUE 6, P1207-1215


Nina Desai, Ph.D., H.C.L.D., Meng Yao, M.S., Elliott G. Richards, M.D., Jeffrey M. Goldberg, M.D.



To evaluate the efficacy of two different in vitro fertilization culture media for blastocyst development, pregnancy, and live birth rate. Global (GB) medium (used without refreshment) and G-TL medium (designed specifically for culture in time-lapse incubators) were compared.


Prospective randomized study of sibling embryo culture in two culture media.


In vitro fertilization clinic.


Women undergoing fresh or frozen cycles using autologous or donor oocytes.



Main Outcome Measure(s)

The primary endpoints were implantation, pregnancy, and live birth rate (LBR) after single blastocyst transfer. Secondary endpoints included embryo morphokinetics, development of good-quality blastocysts, and euploidy rate.


Kinetic data from 10,768 sibling pronucleate embryos cultured in the EmbryoScope were compared. GB embryos initiated compaction earlier and formed morula sooner than their G-TL counterparts. The mean timing for start of blastulation did not differ. The interval between start of blastulation and time of blastocyst formation was observed to be <12 hours for proportionately more GB compared with G-TL–cultured embryos. Despite a higher rate of observed dysmorphisms in GB embryos, the euploidy rate among biopsied blastocysts did not differ between media. A total of 820 single-embryo transfer cycles were performed. Implantation rates were similar between media, independent of whether the embryo transferred was fresh (GB 58.7% vs. G-TL 61.7%) or frozen (GB 64.1% vs. G-TL 60.5%). Live birth rates were also not different. With GB medium, the LBR for fresh and frozen transfers was 54.2% and 53.1%, respectively, as compared with 51.1% and 50%, respectively, with G-TL.


Uninterrupted culture in a time-lapse incubator without medium refreshment was well supported by both media tested. Differences in morphokinetics did not necessarily dictate the superiority of one media over the other. Both pregnancy and LBR were not significantly influenced by choice of culture medium. The euploidy rate was also independent of culture medium.

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