It really depends on where they are. There is a condition where you are pregnant and get uncontrollable itching which only goes away with birth. Otherwise you could try rubbing on coconut oil if the rash is on your skin until you see a doctor- it's harmless but is also both antibacterial and antifungal so win win
Take some benadryl and an Epsom salt bath and call your doctor ☺
Benadryl will help. And c your doctor.
That sounds like a yeast infection. It's very common for pregnant women to get yeast infections epically in the summer time. It will give you a rash because of the itching & irritation off the discharge.
Get checked by your doc just in case... if its just a regular rash try sudocreme x