Effect of hyaluronan-enriched transfer medium on implantation and pregnancy rates after day 3 and day 5 embryo transfers: a prospective randomized study.

OBJECTIVE: To analyze whether the use of a hyaluronan-enriched transfer medium (HETM) increases rates of implantation (IRs) and clinical pregnancy (CPRs), compared with the use of a conventional transfer medium after day 3 and day 5 embryo transfers. DESIGN: Prospective randomized controlled trial. SETTING: An assisted reproduction program in a private tertiary-care hospital in Turkey. PATIENT(S): A total of 1,282 consecutive fresh embryo transfer cycles (825 day 3 and 457 day 5) were randomly allocated into two groups. In 639 women, ET was effected with HETM, and in 643, it was effected with a conventional embryo transfer medium. INTERVENTION(S): Embryo transfer using HETM or conventional embryo transfer medium. MAIN OUTCOME MEASURE(S): Clinical pregnancy rates and IRs were compared with regard to day of embryo transfer, women's age, quality of the transferred embryos, and presence of previous implantation failures. RESULT(S): Overall CPRs and IRs significantly increased with the use of HETM (CPR: 54.6% vs. 48.5%, odds ratio: 1.28, 95% confidence interval: 1.03-1.59; IR: 32% vs. 25%, odds ratio: 1.43, 95% confidence interval: 1.23-1.66, for HETM and control groups, respectively). The number needed to treat (NNT) for one additional pregnancy with routine use of HETM was 17. The beneficial effect was more prominent in women who were >35 years of age (NNT = 7), in women who had previous failed cycles (NNT = 7), and in women who had poor-quality embryos (NNT = 8). CONCLUSION(S): The enrichment of transfer medium with hyaluronan increases CPRs and IRs, both for day 3 and day 5 embryo transfers. The beneficial effect was most evident in women who were >35 years of age, in women who had only poor-quality embryos available for transfer, and in women who had previous implantation failures.