Hyaluronic acid–enriched transfer medium for frozen embryo transfer: a randomized, double-blind, controlled trial

The use of hyaluronic acid–enriched transfer medium does not improve the live birth rate of frozen embryo transfer compared with standard medium.

VOLUME 116, ISSUE 4, P1001-1009


Sofie Shuk Fei Yung, M.B.B.S., Shui Fan Lai, M.B.B.S., Mei Ting Lam, M.B.B.S., Ellen Man Wa Lui, M.B.B.S., Jennifer Ka Yee Ko, M.B.B.S., Hang Wun Raymond Li, M.D., Jacki Yuk Ying Wong, B.Sc., Estella Yee Lan Lau, Ph.D., William Shu Biu Yeung, Ph.D., Ernest Hung Yu Ng, M.D.



To compare the effects of hyaluronic acid (HA)–enriched transfer medium versus standard medium on live birth rate after frozen embryo transfer (FET).


Randomized, double-blind, controlled trial.


Two tertiary fertility centers.


Infertile women aged <43 years at the time of in vitro fertilization undergoing FET.


The women were randomly assigned to 2 groups in a 1:1 ratio. The HA group used EmbryoGlue (Vitrolife, Gothenburg, Sweden) with an HA concentration of 0.5 mg/mL, while the control group used supplemented G-2 (Vitrolife) medium with an HA concentration of 0.125 mg/mL.

Main Outcome Measure(s)

Live birth rate.


Five hundred fifty women were recruited from April 2016 to April 2018 and included in the intention-to-treat analysis. Eight women in the HA group and 5 women in the control group did not undergo FET because the embryos did not survive on thawing. One woman in the HA group cancelled FET because of fever. One woman in the HA group withdrew and received conventional medium. The 2 groups were similar in demographic characteristics. The live birth rates in the HA group and the control group were comparable (25.5% vs. 25.8%; relative risk 0.99; 95% confidence interval 0.74–1.31). The other clinical outcomes were also similar between the 2 groups. Logistic regression showed that the type of transfer medium was not associated with live birth.


The use of HA-enriched transfer medium does not improve the live birth rate of FET compared with standard medium.

Trial Registration Number

NCT02725827 (ClinicalTrials.gov)


Go to the profile of Essam Othman
11 months ago

I would like to thank the authors for their effort to produce this important clinical trial. I have few questions:

1- The authors stated in material and methods that they will perform an intention to treat analysis and a per protocol analysis, but only intention to treat analysis was seen in the tables.

2- Similarly, in material and methods, the authors prespecified a subgroup analysis for the cleavage stage embryos and blastocysts, but the tables don't show that.

3- The statistical issues in sample size calculation (as outlined by the authors in study limitation section) would still keep the question of role of HA transfer medium in FET cycles, not definitively answered.