Bringing awareness of fluid mechanics to reproductive medicine

This chapter describes ongoing engagement between mathematicians at the University of Birmingham and clinical scientists at the Centre for Human Reproductive Science, Birmingham Women’s NHS Foundation Trust focused on sperm motility, and its influence on wider clinical research. Spermmotility deficiencies may be implicated in about half of all cases of infertility, a pathology affecting around one in seven couples in Europe and costing hundreds of millions of pounds per year, in addition to considerable distress. While motility is fundamentally a mechanical process, the physical aspects of this phenomenon have hitherto played a relatively small part in clinical reproductive science research. Classical fluid mechanics- starting with the very low Reynolds number and associated creeping flow-are combined with high speed digital imaging, capture of the flagellar waveform, viscometry, and computational modelling of flowand flagellar forces. Thiswork is providing new tools to assess drug therapies in development, and is contributing to developments internationally in how medical research is approaching sperm motility, for example in the use of viscous-matched media, micro-engineered channels for directing and sorting cells, and in revealing the physiology of fertilisation.