Aerobe Cycling Training in Women With Unexplained Recurrent Pregnancy Loss

In 50% of women with recurrent pregnancy loss (RPL) miscarriages are unexplained, therefore no therapeutic intervention is possible. In a pilot study, women with unexplained RPL showed less endometrial NK cells (eNK) compared to women with a previously uncomplicated pregnancy. It is known that eNK cells are important for embryo implantation during early pregnancy. Investigators presume that high sympathetic activity in these women is related to eNK cell number, function and phenotype and that exercise is an effective intervention to lower sympathetic activity and to influence the immune system, as especially peripheral NK cells have been assumed to be responsive to physical training. The investigators hypothesize that moderate exercise can lower the adrenergic tone of the sympathetic nervous system hereby influencing endometrial NK cells in women with RPL and eventually pregnancy outcome.