Assessment of Effects on Ovarian Activity of a Combined Oral Contraceptive Pill When Preceded by the Intake of ellaOne® or Placebo.

Inclusion Criteria

• •Healthy women aged 18-35 years old
• •BMI \< 30 Kg/m2
• •Not at risk of pregnancy
• •No use of progesterone-only-pill for 3 months before start of treatment cycle
• •No use of implant hormonal contraception for 3 months before start of treatment cycle
• •No use of levonorgestrel intrauterine system for 3 months before start of treatment cycle
• •No use of depo provera for 12 months before start of treatment cycle
• •Able to give informed consent.