WASHINGTON (AP) — Birth control pills work great if women remember to take them every day but missing doses can mean a surprise pregnancy. Now scientists have figured out how to pack a month's supply into one capsule.

The trick: A tiny star-shaped gadget that unfolds in the stomach and gradually releases the drug.

The experimental capsule is still years away from drugstores, but researchers reported Wednesday that it worked as designed in a key test in animals. The Bill and Melinda Gates Foundation is investing $13 million for further development of the once-a-month pill, in hopes of eventuall...