Both pregnancy and oral contraception (mainly when estrogen is included) may precipitate the development of Budd-Chiari syndrome in patients with underlying thrombophilia. By contrast, there is little evidence for such a role of pregnancy and oral contraception in women with portal vein thrombosis. In pregnant women, special modalities for anticoagulation are required, whereas the management of portal hypertension can be similar to that recommended in other diseases and settings. Hereditary hemorrhagic telangiectasia may deteriorate during pregnancy and improve after delivery. Hepatic sinusoidal dilatation and hepatic peliosis are classic complications of long-term use of oral contraceptives. The impact of pregnancy or oral contraceptives on the natural history on hemangioma and focal nodular hyperplasia appears to be limited. Preeclampsia, a liver disease unique to pregnancy, may be complicated by life-threatening liver vascular involvement, especially when the syndrome of hemolysis, elevated liver enzymes, and low platelet count (HELLP syndrome) is present.