The effect of protein supplement concentration in embryo transfer medium on clinical outcome of IVF/ICSI cycles: a prospective, randomized clinical trial

The aim of this prospective, randomized clinical trial (RCT) was to evaluate whether the supplemental protein concentration in embryo transfer (ET) medium affects the clinical outcomes in IVF-ET. A total of 750 patients undergoing IVF-ET who met the inclusion criteria were randomly divided into three groups, according to the concentration of synthetic serum substitute (SSS) in ET medium as follows: 10% (Group A), 20% (Group B) and 50% (Group C). The patient characteristics and embryology data were all similar among the groups. The rates of implantation, clinical pregnancy and live birth were compared. Clinical pregnancy (44.61%, 48.79% and 45.49%), multiple pregnancy (24.18%, 28.71% and 25.0%), implantation (28.21%, 30.68% and 29.86%) and live birth (41.67%, 43.96% and 41.70%) rates in the three groups (A, B and C, respectively) showed no significant differences. This RCT demonstrates that supplemental protein concentration in the ET medium does not affect the treatment outcomes in IVF-ET. There was no statistical evidence to support the hypothesis that supplemental protein concentration in the ET medium influences treatment outcomes in IVF-ET.