There is a skin rash that is caused by pregnancy. You need to tell your OB about it because it only gets worse.
What you seem to be having is called pruritic urticarial papules and plaques of pregnancy.It shows up as red, irregularly shaped,itchy, flat or slightly raised patches with a light halo around them. Typically, the rash appears during the last 2 to 3 weeks of pregnancy and occasionally during the last few days. Usually, the rash clears up promptly after delivery and does not recur during subsequent pregnancies.
I hope it helps. Take care and pls do keep me posted on how you are doing or in case you have any additional doubts. Kind regards.