Cycle Control Assessment of a Combined Oral Contraceptive Containing Estetrol and a Progestin P1 or P2

Inclusion Criteria: * Women willing to use a Combined Oral Contraceptive for 6 subsequent cycles * Good physical and mental health * Regular menstrual cycle (24-35 days) prior to screening * Body mass index between (≥) 18 and (≤) 30 kg/m2 Exclusion Criteria: * Previous use of any hormonal contraceptive method during the last 3 months prior to randomisation (only applicable for women who are not using a hormonal contraceptive method at the time of screening) * Previous use of progestogen-only contraceptive methods during the last 3 months or during the last 6 months for depot progestogen preparations or an injectable hormonal method of contraception * Use of phytoestrogens * No spontaneous menstruation has occurred following a delivery or abortion * Breastfeeding or within 2 months after stopping breastfeeding prior to the start of study medication and no spontaneous return of menstruation * Status post-partum or post-abortion within a period of 2 months before screening * Pregnancy during accurate hormonal contraceptive use in the past * Intention to become pregnant during the study * An abnormal cervical smear within one year before study start * Untreated Chlamydia infection * Known or suspected breast cancer or a history of breast cancer * A history of (within 12 months) alcohol or drug abuse * Any clinically relevant abnormality * Contraindications for the contraceptive steroids used in the clinical trial * Use of antihypertensive drugs or use of medications interacting with the contraceptive steroids used in the clinical trial * Administration of any other investigational drug within 2 months prior to screening