I'm pregnant and have rash. Ob ordered a bile test. Whats this?

Cholestasis? Your doctor is probably concerned about the possibility of cholestasis of pregnancy which is a condition that typically develops during the last several weeks of pregnancy. It typically causes severe itching all over the body without a rash. Serum bile acid levels are elvated which is the reason why your doctor is checking this. This condition is associated with adverse pregnancy outcome.