I Have Endometriosis And Polyovarin Cystic Disease I Have This

I have endometriosis and polyovarin cystic disease i have this reacquiring very itchy rash that develops only below my belly button I have had a few miscarages and the rash shows up at the same time as a pregnancy and only goes away after a very short very heavy period i think my body is having an auto immune response and killing the baby could this be the cause of the rash ?