Fitbit has just launched what they say is one of their most requested features: Period tracking. The app and smartwatch can now show you where in your cycle you are, the better to correlate cycle data with your nutrition and sleep.

"Oooh, how bout my sperm meet your eggs tonight?" asked no man ever.

Infertility is rough enough without headlines implying your yoga practice is to blame. A recent study found that certain flame-retardant chemicals may make it harder for you to have a baby, but despite the downward-dog stock photos, yoga mats weren't involved in the research.

Pregnancy is the most common reason for a missed period, but it isn't the only reason. In this video, SciShow explains a few other reasons you might skip a period.