SAN FRANCISCO — Check serum bile acid levels to determine if severe itching during pregnancy is the result of intrahepatic cholestasis of pregnancy, advises a dermatologic pathologist.
“Intrahepatic cholestasis of pregnancy is about the only dermatosis of pregnancy that has poor outcomes for the unborn,” Dr. Senait W. Dyson said at a meeting sponsored by Skin Disease Education Foundation.
An uncommon problem in the United States, intrahepatic cholestasis of pregnancy (also called prurigo gravidarum or obstetric cholestasis) is a reversible form of cholestasis that presents in late pregnancy and persists until delivery.
The disease increases the risk of intrauterine fetal distress and leads to a three- to fourfold increase in the risk of stillbirth.
It typically presents during the third trimester and resolves within days after delivery. Clinically, the problem is characterized by generalized, severe pruritus without primary skin lesions, said Dr. Dyson, director of dermatopathology at the University of California, Irvine. Involvement of the palms and soles is common. You'll seldom see jaundice with intrahepatic cholestasis of pregnancy.
The main diagnostic finding is increased serum bile acids in all cases, resulting from impaired bile flow. Elevated serum bile acid levels greater than 4.07 mcg/mL (10 micromol/L) in these patients can reach as high as 16 mcg/mL (40 micromol/L), she said.
Some patients will have abnormal liver function tests. Histology is nonspecific, and immunofluorescence tests will be negative.
Prolonged disease causes vitamin K deficiency and increases the risk for bleeding in the mother. It is not clear whether the bleeding risk increases in the infant. Check prothrombin times in women with intrahepatic cholestasis of pregnancy, Dr. Dyson advised. Women with increased prothrombin times should get vitamin K injections.
“Treatments that I use for other cholestasis diseases are not helpful in this condition,” she noted.
Antihistamines will help control the pruritus. Ursodeoxycholic acid (UDCA), the only approved medication to treat primary biliary cirrhosis, also helps improve pruritus in patients with intrahepatic cholestasis of pregnancy. Dr. Dyson said that most medical centers, including her institution, dose UDCA at 14 mg/kg per day t.i.d. to treat intrahepatic cholestasis of pregnancy from the time of diagnosis until delivery. Some clinicians suggest that dosages as high as 20–25 mg/kg per day t.i.d. might be better.
Delivery by 38 weeks' gestation is advisable, and some physicians suggest elective delivery by 37 weeks to decrease the risk of stillbirth, but it's not clear whether the potential benefits of delivering at 37 weeks outweigh the risks from preterm delivery, Dr. Dyson said.
“It's definitely agreed that patients should have frequent nonstress tests” and biophysical profiles to assess for fetal stress starting at 34 weeks' gestation, she said.
The incidence of intrahepatic cholestasis of pregnancy worldwide ranges from 10 to 760 cases per 10,000 pregnancies, with a higher incidence seen in Latin America (especially in Chile and Bolivia) and low rates in the United States and Europe.
Dr. Dyson reported having no conflicts of interest.
Skin Disease Education Foundation and this news organization are wholly owned subsidiaries of Elsevier.