Comparison of two monophasic culture systems

Abstract

Objective Comparison of a low lactate monophasic culture medium (medium 1) to a KSOM based monophasic culture medium (medium 2). Design Prospective sibling oocyte study. Materials and methods 115 patients undergoing ICSI between January and May 2019 were included in this study. A 60mm dish was prepared with 30µL drops covered with light mineral oil and pre-equilibrated at least 16 hours at 37°C 6.5%CO2/5%O2 to maintain a pH of 7.2 to 7.3. Both media were in the same dish. Oocytes were randomly distributed among the two culture-media immediately post-ICSI. Fertilization was evaluated at 17 ± 1-hour post-ICSI. 2PN zygotes with clearly visible pronuclei were cultured through day 6. Blastocyst quality was evaluated at days 5 and 6. Ploidy data was included if available. Results 115 patients with an average age of 37.4 years had 1,308 embryos cultured in media 1 (640) and media 2 (655). Day 5 and day 6 blastocysts yields were 34% and 29%, respectively for media 1 and 14% and 19%, respectively for media 2. Overall, blastocyst-quality was similar between both media 1(50.9%) and medium 2 (51.6%). A non-significant trend showed medium 1 to produce a higher proportion of good-quality blastocysts on Day 5 (67% vs 56% when compared to medium 2 (P=0.09, paired sample t-test). Conversely, medium 2 had more good quality blastocysts on Day 6, than medium 1 (difference of 8%, P=0.03, paired sample t-test). A sub-set of 27 patients (N=95) had PGT-A on D5 Blastocysts (50, medium 1 vs 45, medium 2). The proportion of euploid embryos was similar between the two media with both demonstrating 44% euploidy rate on day 5. Conclusions A wide variety of commercially available media have been formulated for the culture of human pre-implantation embryos. A meta-analysis concluded “there is insufficient evidence to support or refute the use of any specific culture medium1”. Previous reports indicated that a low lactate medium yielded significantly more euploid blastocysts when compared to a monophasic medium with higher lactate concentration2. Our data indicated a trend towards a higher number of day 5 euploid blastocysts in a low lactate medium than a medium with higher lactate. Even if the present study suffers from constraints of sample size and lack of a more representative demography, it does indicate robustness of low-lactate media in supporting embryo development and ploidy in a sibling split experimental design. Disclosures None