The Male Factor in Recurrent Pregnancy Loss and Embryo Implantation Failure

Only recently have we come to ask what role the male might play in pregnancy loss and embryo implantation failure, beyond contributing an abnormal set of paternal chromosomes at fertilization. Recent evidence suggests that these situations may be related to the transmission of previously unrecognized chromosomal microdeletions or via the epigenetic dysregulation of embryonic gene function by spermatozoal micro-RNAs. In addition, the composition of seminal plasma has been found to be highly complex, containing factors that play important roles in altering the uterine environment and the female immune system permissive of embryo implantation and trophoectoderm outgrowth leading to successful pregnancy. Much of the information presented in this chapter is quite new, suggesting tantalizing hints for clinical application through future translational research.