Inclusion Criteria:
* Sexually active women, at risk for pregnancy and willing to use a contraceptive for at least 4 cycles
* Women with regular menstrual cycles with an intermenstrul period between 21 and 35 days
* An age between 18 and 50 years at time of screening
* Body mass index ≥18 and ≤30;
* Good physical and mental health;
* Choose either no hormonal contraception or one of the specific contraceptives under investigation
* Willing to give informed consent in writing
Exclusion Criteria:
* Contraindications for contraceptive steroids:
* Presence or a history of venous or arterial thrombotic/thromboembolic events (e.g. deep venous thrombosis, pulmonary embolism, myocardial infarction) or of a cerebrovascular accident;
* Precence or history of prodromi of a thrombosis (e.g. transient ischaemic attack, angina pectoris);
* History of migraine with focal neurological symptoms;
* Diabetes mellitus with vascular involvement;
* The presence of a severe or multiple risck factor(s) for venous or arterial thrombosis (to be judged by the (sub)-investigator).
e.g. increasing age; smoking (with heavier smoking and increasing age the risk further increases, especially in women over 35 years of age); a positive family history (i.e. venous or arterial thromboembolism ever in a sibling or parent at an age\< 40 years o); obesity (body mass index over 30 kg/m2); dyslipoproteinaemia; hypertension, migraine, valvular heart disease, atrial fibrillation; prolonged immobilization, major surgery any surgery to the legs, or major trauma (until two weeks after full remobilization); systemic lupus erythematosus; haemolytic uraemic syndrome; chronic inflammatory bowel disease (Crohn's disease or ulcerative colitis); sickle cell disease;
* Severe dyslipoproteinemia
* Blood pressure above 140/90 mmHg
* Known hereditary or acquired predisposition for venous or arterial thrombosis, such as APC resistance, antithrombin-lll-deficiency, protein C deficiency, protein S deficiency, hyperhomocysteinaemia and antiphospholipid antibodies (anticardiolipin antibodies, lupus anticoagulant);
* Pancreatitis or a history thereof if associated with severe hypertriglyceridaemia;
* Presence or history of severe hepatic disease as long as liver function values have not returned to normal;
* Presence or history of liver tumors (benign or malignant);
* Known or suspected sex steroid-influenced malignancies (e.g. of the genital organs or the breasts);
* Undiagnosed vaginal bleeding
* Known or suspected pregnancy
* Hypersensitivity to the active substances or to any of the excipients of the investigational product
* An abnormal cervical smear (i.e.: dysplasia, cervical intraepithelial neoplasia (CIN), SIL, carcinoma in situ, invasive carcinoma) at the screening evaluation
* Clinically relevant abnormal laboratory data as judged by the investigator;
* Post-partum (6 months from delivery)
* Breastfeeding or 2 months from breastfeeding ending
* Present use or use in the last 2 months of the following drugs: phenytoin, barbiturates, primidone, carbamazapine, oxcarbazepine, topiramate, felbamate, rifampicin, nelfinavir, ritonavir, griseofulvin, ketoconazole, sex steroids (other than pre- and post-treatment contraceptive method) and herbal remedies containing Hipericum perforatum (St John's Wort);
* Administration of any other investigational drugs and/or participation in other clinical trial in the last 2 months.
* Present use of any oral contraceptive.
