Single versus sequential culture medium: which is better at improving ongoing pregnancy rates? A systematic review and meta-analysis

Abstract

This study aimed to evaluate if single medium is better than sequential medium at improving ongoing pregnancy rates in patients undergoing assisted reproductive technology (ART) procedures. The data featured in this meta-analysis were extracted from four randomized controlled trials yielded from a systematic search carried out on electronic databases. The primary endpoint was ongoing pregnancy rate. Secondary endpoints included clinical pregnancy and miscarriage rates. The endpoints for ongoing pregnancy rate were also analyzed based on the time at which the embryo transfers were performed: cleavage stage (day 2/3) and/or blastocyst stage (day 5/6). There were no significant differences between single and sequential medium for clinical pregnancy (RR=1.09; 95%CI=0.83-1.44; p=0.53), ongoing pregnancy (RR=1.11; 95%CI=0.87-1.40; p=0.39), or miscarriage rates (RR=0.89; 95%CI=0.44-1.81; p=0.74). No significant difference was found for ongoing pregnancy rate (RR=1.29; 95%CI=0.93-1.78; p=0.12) between single and sequential medium when only trials in which embryos were transferred at the blastocyst stage were included. In conclusion, the choice of embryo culture approach - single or sequential medium - did not affect the ongoing pregnancy rates of patients undergoing ART cycles.

‘There is only one thing that is truly important in an IVF laboratory: everything’ Cairo Consensus Guidelines on IVF Culture Conditions

“…Culture media -sequential or 'singlestep' media for embryo culture A recent Cochrane Review (Youssef et al, 2015) concludes that there are no differences in outcomes between the two culture systems, and this conclusion is supported by other systematic reviews (Dieamant et al, 2017;Sfontouris et al, 2016). However, Sfontouris et al (2016) concluded that: 'Although using a single medium for extended culture has some practical advantages and blastocyst formation rates appear to be higher, there is insufficient evidence to recommend either sequential or single-step media as being superior for the culture of embryos to days 5/6.…”

“…The suggestion that either the single-step SOM approach or sequential culture is better is not based on scientific arguments and cannot be decided after evaluation of the literature. More than a thousand papers and abstracts have been written about culture media systems and a considerable number of thorough reviews have been published comparing the two approaches (Dieamant et al, 2017;Sfontouris et al, 2016;Youssef et al, 2015). Analyses like this are unfortunately compromised by the quality of the original comparative studies and a multitude of confounders affecting laboratory results.…”

“…This was illustrated by the work of David Gardner and colleagues describing the first sequential culture medium system G1 and G2, nearly 20 years ago (reviewed in Niederberger et al, 2018). Those studies fulfilled the Harper model criteria in short order, although later RCT comparing sequential media against single-step KSOM-derived culture in systematic reviews did not show differences (Dieamant et al, 2017;Sfontouris et al, 2016).…”

Effect of the sexual abstinence period recommended by the World Health Organization on clinical outcomes of fresh embryo transfer cycles with normal ovarian response after intracytoplasmic sperm injection

“…We used two types of media for a stable culture condition. In addition, recent systematic reviews and meta‐analyses reported that there is insufficient evidence to recommend either sequential or one‐step media as being superior for culturing human embryos (Sfontouris et al., ), and sequential or one‐step media also did not affect the ongoing pregnancy rates of patients undergoing ART cycles (Dieamant et al., ). We did not limit the age of men for recruitment and did not investigate the relationship between SAP and semen parameters, such as sperm function.…”

Continuous embryo culture elicits higher blastulation but similar cumulative delivery rates than sequential: a large prospective study

“…Recently, Sfontouris and colleagues performed a metaanalysis of the main studies related to this topic and concluded that a higher blastocyst rate, as well as superior morphological quality, may be achieved when a continuous culture media is used [12]. Yet, this did not result into better clinical outcomes, as supported also by the meta-analysis published by Diemant and colleagues in 2017 [12,13].…”