WHAT: BBT stands for Basal Body Temperature. Your basal body temperature is your temperature when you’re fully at rest.

WHY: Ovulation is said to cause a slight increase in basal body temperature. Therefore you will be most fertile during the two to three days before your temperature rises. When you track your BBT each morning, you will be providing Glow with another important variable in determining your most fertile days.

HOW: You can take your BBT by using a digital oral basal thermometer. (These types of thermometers are readily available at your local drugstore.) To take you BBT, take your temperature first thing in the morning, before you get out of bed or move around too much. You can use Glow Genius to set yourself a daily reminder for the hour of your choosing.