The metabolic effects of hormonal contraceptives differ when administered by oral or systemic routes. The oral route magnifies the hepatic production of hormone sensitive proteins including lipoproteins, clotting factors and inflammatory proteins such as CRP. These effects are due to the first pass of hormone to the liver from the portal circulation. The first pass hepatic effect also reduces the systemic exposure to orally administered estrogen and progestin, due to glucuronidation and sulfation of sex hormones and excretion in the bile. Systemic administration by the patch is more analogous to physiologic hormone release from the ovary, as it avoids the first pass effect and the peripheral tissues are exposed to higher hormone concentrations than with oral administration. Conversely, the liver may have a lower exposure to hormone by patch administration than by oral administration.