History/Physical/Lab. Cholestasis is diagnosed by doing a complete medical history, physical examination, and blood tests that evaluate liver function, bile acids, and bilirubin. Additionally, an ultrasound can de done to rule out gall bladder stones causing blockage. 1-2 preg/1000 is affected by cholestasis of pregnancy. It may be related to adverse pregnancy events like preterm labor, or at worse, stillbirth.