Blastocyst utilization rates after continuous culture in two commercial single-step media: a prospective randomized study with sibling oocytes.
PURPOSE
The aim of this study is to determine whether blastocyst utilization rates are different after continuous culture in two different commercial single-step media.


METHODS
This is a paired randomized controlled trial with sibling oocytes conducted in infertility patients, aged ≤40 years with ≥10 oocytes retrieved assigned to blastocyst culture and transfer. Retrieved oocytes were randomly allocated to continuous culture in either Sage one-step medium (Origio) or Continuous Single Culture (CSC) medium (Irvine Scientific) without medium renewal up to day 5 post oocyte retrieval. Main outcome measure was the proportion of embryos suitable for clinical use (utilization rate).


RESULTS
A total of 502 oocytes from 33 women were randomly allocated to continuous culture in either Sage one-step medium (n = 250) or CSC medium (n = 252). Fertilization was performed by either in vitro fertilization or intracytoplasmic sperm injection, and embryo transfers were performed on day 5. Two patients had all blastocysts frozen due to the occurrence of severe ovarian hyperstimulation syndrome. Fertilization and cleavage rates, as well as embryo quality on day 3, were similar in the two media. Blastocyst utilization rates (%, 95% CI) [55.4% (46.4-64.1) vs 54.7% (44.9-64.6), p = 0.717], blastocyst formation rates [53.6% (44.6-62.5) vs 51.9 (42.2-61.6), p = 0.755], and proportion of good quality blastocysts [36.8% (28.1-45.4) vs 36.1% (27.2-45.0), p = 0.850] were similar in Sage one-step and CSC media, respectively.


CONCLUSIONS
Continuous culture of embryos in Sage one-step and CSC media is associated with similar blastocyst development and utilization rates. Both single-step media appear to provide adequate support during in vitro preimplantation embryo development. Whether these observations are also valid for other continuous single medium protocols remains to be determined.


CLINICAL TRIAL REGISTRATION NUMBER
NCT02302638.
['Sfontouris|Ioannis A|IA|', 'Kolibianakis|Efstratios M|EM|', 'Lainas|George T|GT|', 'Venetis|Christos A|CA|', 'Petsas|George K|GK|', 'Tarlatzis|Basil C|BC|', 'Lainas|Tryfon G|TG|']
D000328:Adult D001755:Blastocyst D003470:Culture Media D046149:Embryo Culture Techniques D004624:Embryo Transfer D005260:Female D005307:Fertilization in Vitro D006801:Humans D050498:Live Birth D054315:Oocyte Retrieval D009865:Oocytes D011247:Pregnancy D035781:Siblings D020554:Sperm Injections, Intracytoplasmic
Utilization rate Continuous culture Blastocyst formation Embryo culture Single step