Smoking (especially women >35 yr); diabetes; overwt; high BP; heart valve or certain heart rhythm disorder; inflammation of veins (superficial phlebitis); varicose veins; thrombosis, heart attack or stroke; migraine; epilepsy; high cholesterol or triglycerides; breast cancer; liver or gallbladder disease; Crohn's disease or ulcerative colitis (chronic inflammatory bowel disease); SLE; haemolytic uraemic syndrome; sickle cell disease; operation or limited movements for a long period of time; increased risk of blood clots in patients who recently gave birth; condition that occurred for the 1st time or worsened during pregnancy or previous use of sex hormones (eg, hearing loss, porphyria, herpes gestationis, Sydenham's chorea); chloasma (avoid excessive sun or UV light exposure). High risk of thrombosis especially in patients who restart treatment after a ≥4 wk interruption of therapy. Discontinue treatment if signs of thrombosis occur. Risk of breast cancer. Concomitant use w/ primidone, phenytoin, phenobarb, carbamazepine, oxcarbazepine, topiramate, felbamate, rifampicin, ritonavir, nelfinavir, nevirapine, efavirenz, boceprevir, telaprevir, griseofulvin, bosentan, St. John's wort; ciclosporin, lamotrigine; combination drug regimen ombitasvir/paritaprevir/ritonavir w/ or w/o dasabuvir. May affect any blood or urinary test. Patients w/ hepatitis C. Intolerance to some sugars. Pregnancy & lactation.