Contraceptive pill with no side-effects in the pipeline

Scientists in the United States are developing a new contraceptive pill with no side-effects.

A team at Brigham and Women's Hospital in Boston believe that the drug will provide an alternative to the current pill, which can cause side-effects such as mood swings, blood clots and a slightly increased risk of breast cancer.

The scientists say the drug will be administered by way of a patch which will block a gene that produces a protein called ZP3, which allows the sperm to bind to the outer layer of a woman's egg.

Once the protein is blocked it would make it impossible for the sperm to enter the egg and fertilise it.

The therapy is based on a process called RNA interference, where specific genes are turned off, but to date it has only been tested in mice and human kidney cells.

Researcher Dr. Zev Williams says human trials of the pill are a decade away but an alternative to hormonal contraceptives is long due.

Dr. Williams says there is no contraceptive drug that is non- hormonal and reversible so he is trying to think about contraception in a new way which will require a great deal of time and effort.

Dr. Williams presented the findings at the American Society for Reproductive Medicine conference in Washington DC.