A randomized comparison of sequential and single step culture media systems on sibling oocytes: complete P-1 versus single step medium

Blastocyst culture using single versus sequential media in clinical IVF: a systematic review and meta-analysis of randomized controlled trials

“…We further examined 23 studies for eligibility: -A total of three studies were excluded: Two studies used Fertilization and then Cleavage Medium and not a system for Cleavage and then Blastocyst [20,21], and one study was excluded because a different oxygen tension was used in the different groups [22]. -A total of 20 studies were included in this review: Ten studies that randomized oocytes/zygotes [23][24][25][26][27][28][29][30][31][32] and two studies that randomized women [33,34] were included in the forest plots; however, six studies that randomized oocytes/zygotes [35][36][37][38][39][40] and two studies that randomized women [41,42] were not included in the forest plots because it was not possible to extract data for the metaanalyses.…”

“…Nine studies were deemed to be at high risk of bias in at least one domain. One was considered at high risk of selection bias because the allocation was not properly concealed [29]; three were at risk of detection bias because the embryologist who assessed the embryo characteristics was not blinded to the allocation [30,32,37]; three were at high risk of attrition bias because of loss of participants [33] or because not all embryos were followed up until the blastocyst stage [24,36]. All the included studies were judged to be at low risk of reporting bias, and two studies were judged to be at high risk of other bias: one study because only preliminary results were published [41] and another study because two types of incubators were used and it is unclear whether the distribution of the embryos in each group was similar or not [42].…”