Which one of the following is true about norplant?

Norplant is implanted under the skin in the upper arm of a woman, by creating a small incision and inseing the capsules in a fanlike shape. Once inseed, the contraceptive works within 24 hours and lasts up to five years. Norplant should not be used in women with liver disease, breast cancer or blood clots. It releases levenorgestrol and failure rate is 0.1/100 women year. It inhibits ovulation.