Patients with ICP should be considered to have a high-risk pregnancy. Once the diagnosis of ICP is suspected, usually because of generalized pruritus, it should be confirmed by liver function tests, and other causes of cholestasis should be ruled out. Treatment with UDCA is effective in ameliorating the cholestasis and is especially useful in severe forms or when there is a history of sudden fetal death in a previous pregnancy. The understanding of the pathogenesis of ICP has recently progressed as the result of the discovery of several defects in the MDR3 gene in isolated affected patients. More studies of this and other genes that regulate bile flow, linked with careful clinical observations to rule out unsuspected chronic liver disease not related to pregnancy, should lead to the discovery of the pathogenesis of this enigmatic disorder.