The purpose of the study is to examine how well three months preceding use of Cerazette progestin only pill predicts the bleeding pattern during following Nexplanon implant use.

Inclusion Criteria:

• Healthy women, 18-40 years of age
• regular menstrual cycle (period 23-35 days)

Exclusion Criteria:

• -Immediate previous use of progestin only contraception within 2 months
• Known or suspected pregnancy
• Acute tromboembolic disorder
• Presence or history of hepatic disease, as long as the liver function values have not returned to normal
• Undiagnosed vaginal bleeding
• Known or suspected sex-steroid influenced malignancies (e.g. breast cancer)
• Hypersensitivity to the active substances or to any of the excipients of the medicines
• Pregnant or breast feeding within 6 weeks
• The use of other medicinal products that might interact with contraceptive steroids and affect the efficacy of contraceptives and/or might may lead to bleeding irregularities (especially medicines that induce the liver enzyme systems such as cytochrome P450). Examples of active substances are: phenytoin, phenobarbital, primidone, bosentan, carbamatzepine, rifampicin and medicinal products or herbal preparations containing ST.John's wort and to a lesser extend oxcarbazepine, topiramate, felbamate and griseofulvin.