Natural Cycles birth control app is the first of its kind to be considered an "approved medical device"

Elina Berglund helped find the Higgs boson particle. But when the Large Hadron Collider finished its first run in 2012, the Swedish particle physicist felt ready for a change. "It's impossible to top that," she says. "So I thought, why not try something completely different?"

How does Natural Cycles work?

A woman is fertile up to 6 days per cycle. The fertile window ends with the day of ovulation and begins up to 5 days before, depending on sperm survival. Natural Cycles carefully studies your body temperature to find your ovulation day and fertility.