Cortisone injection while pregnant?

I found out I was pregnant 4 days before I went to the orthopedic surgeon to have him look at my ankles. I have a preexisting condition called a tarsal coalition and it has been getting progressively worse for the last year! I have spent hundreds on good quality shoes and braces with little to no relief. I soak in epsom salts right now with almost no relief! Has anyone had injections while pregnant? I've been reading up on it and it seems that they are safe... I go to my OB monday for my 20wk appt and will ask them as well. This is affecting my quality of life. I have a very hard time working. I can't walk when I get home so nothing gets done and it is the most excruciating pain! Please help!