Mifepristone ovarian function study

This study is for women who are using Implanon (a small rod implanted under the skin of the arm that prevents pregnancy). A common problem with Implanon is irregular bleeding. This study is testing whether a medicine called mifepristone, with or without oestrogen, can help reduce unexpected bleeding while keeping Implanon working as a contraceptive. Participants will have ultrasound scans, cervical mucus checks, and blood tests over 4 weeks. You may be eligible if: - You are a woman between 18 and 45 years old - You have been using Implanon for at least 3 months - You are willing to have regular blood tests, vaginal ultrasounds, and cervical mucus collections over a 4-week period - You are willing to use condoms for the entire study period You may NOT be eligible if: - You are pregnant - You have had a heart attack, stroke, or blood clot in a vein - You have high blood pressure (above 160/95) - You have severe liver or kidney disease - You have a history of focal migraines - You have or have had breast cancer or genital cancer - You have a known sensitivity to ethinyl oestradiol or lactose - You are taking phenytoin, carbamazepine, or phenobarbitol - You are breastfeeding Talk to your doctor about whether this trial might be right for you.