RESUMEN
OBJECTIVE: Several studies have been performed up to date, in order to assess whether the addition of hyaluronan (HA) in human embryo culture could improve the probability of pregnancy, leading, however, to controversies. The aim of the present study was to analyze whether the use of a HA-enriched transfer medium increases clinical pregnancy (PR) and implantation rates (IR), compared with the use of a conventional transfer medium. PATIENTS AND METHODS: All IVF/ICSI attempts from unselected women were included from January 2009 to July 2009 (study group). All embryo transfers (ET) were performed using a HA-enriched media. IVF outcomes of this series were compared to those of a retrospective series, including continuous IVF/ICSI attempts from January 2008 to July 2008 where ET were classically performed (control group). Primary endpoints were PR and IR, compared firstly in all patients of the study and control groups and then regarding woman's age and presence of previous implantation failures. RESULTS: In all, 292 (study group) and 296 (control group) IVF/ICSI attempts were included. PR (32.9%) and IR (22.2%) were significantly increased in the study group compared with those of the control group (PR=25.0%; IR=15.4%; p<0.05). We observed that PR and IR were statistically increased only in subgroups of women >or=35 years or in case of at least one previous implantation failure (p<0.05). DISCUSSION AND CONCLUSION: The use of a HA-enriched embryo transfer medium is beneficial since associated with increased PR and IR. This type of media should be used in infertile women >or=35 years or needing at least a second IVF/ICSI attempt.