Immune suppressant steroids such as Prednisone have been used for patients with multiple miscarriages and with repeated I.V.F. failures. An article by Robertson in Human Reproduction, September 2nd 2016, surveys a role of steroids in assisted reproduction. While steroids may be of value in patients with immunological problems, there would seem very little evidence to use steroids in patients who undergo assisted reproduction who do not have a pre-existing immune problem. There is concern also that steroids may even be harmful.
My advice is in the main, do not use steroids unless there is a previous immunological disorder.