The fingernail-size microchip implant holds enough 30-microgram daily doses of levonorgestrel—a hormone already used in several contraceptives—to last for 16 years. Women who received the implant under the skin of buttocks, upper arm or abdomen would also get a remote control that allows them to halt or restart the implant whenever they like, according to MIT Technology Review.

MicroCHIPS, the MIT startup behind the birth control implant, developed a clever design for a titanium and platinum seal that temporarily melts when an internal battery sends an electric charge running through the seal. That lasts just long enough for the melted seal to release the daily dose of levonorgestrel from the microchip reservoirs.

The microchip technology's latest mission first came about when Bill Gates visited the MIT lab of Robert Langer and challenged researchers to come up with a birth control method that women could control themselves and would also last for many years. Langer, an MIT professor who already holds 1,050 patents worldwide, thought of using the controlled release microchip technology that he and his colleagues had developed in the 1990s.

MicroCHIPS had previously demonstrated how the microchip technology could release daily doses of an osteoporosis drug during human clinical trials detailed in the 16 Feb 2012 online edition of the journal Science Translational Medicine. The new application for the microchips—each measuring 20 x 20 x 7 millimeters—could potentially revolutionize the level of control women have over their birth control technologies.

The biggest difference that the MicroCHIPS technology brings comes from giving women control over starting and stopping birth control regimens that can otherwise work for years without requiring regular attention. By comparison, existing contraceptive implants require a trip to the local clinic or hospital for removal if a woman wants to stop using the implant.

Any device offering wireless control for its users also runs the risk of being hacked. But Robert Farra, president and CEO of MicroCHIPS, told BBC News that their technology included secure encryption to prevent outsiders from blocking or reprogramming the implants wirelessly. As an added precaution, the remote control can only communicate with the microchip implant across a distance equivalent to skin contact.