Implants

Implants

Small, flexible rods or capsules placed under the skin of the upper arm; contains progestogen hormone only

How it works: 
Thickens cervical mucous to block sperm and egg from meeting and prevents ovulation
Effectiveness to prevent pregnancy: 
>99%
Comments: 
Health-care provider must insert and remove; can be used for 3–5 years depending on implant; irregular vaginal bleeding common but not harmful