Cryopreservation of human sperm: efficacy and use of a new nitrogen-free controlled rate freezer versus liquid nitrogen vapour freezing.

Preservation of spermatozoa is an important aspect of assisted reproductive medicine. The aim of this study was to investigate the efficacy and use of a recently developed liquid nitrogen and cryogen-free controlled rate freezer and this compared with the classical liquid nitrogen vapour freezing method for the cryopreservation of human spermatozoa. Ten patients entering the IVF programme donated semen samples for the study. Samples were analysed according to the World Health Organization guidelines. No significant difference in total sperm motility after freeze-thawing between the new technique and classical technique was demonstrated. The advantage of the new freezing technique is that it uses no liquid nitrogen during the freezing process, hence being safer to use and clean room compatible. Investment costs are higher for the apparatus but running costs are only 1% in comparison with classical liquid nitrogen freezing. In conclusion, post-thaw motility of samples frozen with the classical liquid nitrogen vapour technique was comparable with samples frozen with the new nitrogen-free freezing technique. This latter technique can thus be a very useful asset to the sperm cryopreservation laboratory.

Relationship between hyaluronic acid binding assay and outcome in ART: a pilot study.

The sperm-hyaluronan binding assay (HBA) is a diagnostic kit for assessing sperm maturity, function and fertility. The aim of this prospective cohort pilot study was to evaluate the relationship between HBA and WHO sperm parameters (motility, concentration and detailed morphology) and possible influence of sperm processing on hyaluronic acid binding. A cohort of 68 patients undergoing a first combo in vitro fertilisation/intracytoplasmic sperm injection treatment after failure of three or more intrauterine insemination cycles were included in the study. Outcome measures studied were fertilisation rate, embryo quality, ongoing pregnancy rate and cumulative pregnancy rate. HBA outcome improved after sperm preparation and culture, but was not correlated to detailed sperm morphology, concentration or motility. HBA did not provide additional information for identifying patients with poor or absent fertilisation, although the latter had more immature sperm cells and cells with cytoplasmic retention present in their semen. HBA outcome in the neat sample was significantly correlated with embryo quality, with miscarriage rates and ongoing pregnancy rates in the fresh cycles, but not with the cumulative ongoing pregnancy rate. No threshold value for HBA and outcome in combo IVF/ICSI treatment could be established. The clinical value for HBA in addition to routine semen analysis for this patient population seems limited.