Single fresh and frozen–thawed blastocyst transfer using hyaluronan-rich transfer medium

The purpose of this prospective randomized study was to evaluate use of a hyaluronan-rich transfer medium in fresh and frozen–thawed single blastocyst transfer. The study included 279 single blastocyst transfers in women aged <37 years in their first, second or third treatment cycle. According to the type of single blastocyst transfer (fresh elective or frozen–thawed) the women were divided into two study and two control groups. In both study groups (n = 130) transfers were performed using hyaluronan and in the control groups (n = 149) a conventional transfer medium was used. The results indicate that fresh elective single blastocyst transfer with hyaluronan results in significantly higher pregnancy rates in a selected subgroup of women; those with ≥2 blastocysts developed to day 5 and a previous implantation failure (55% versus 10%; P = 0.012). Overall pregnancy rates after fresh elective and frozen–thawed single blastocyst transfer were similar in both study and control groups.