WHAT: BMI stands for Body Mass Index. Your BMI is a measure of your body fat based on height and weight.

WHY: According to the American Society of Reproductive Medicine, BMI can play an important role in your fertility. Studies have shown that having both too high a BMI (higher than 35) or too low a BMI (lower than 19) can increase the amount of time it takes to become pregnant.

HOW: You can input your BMI into Glow in one of two ways. You can either link your Myfitnesspal account to Glow in the settings menu. Or you can update your weight daily in the Glow log. Glow will then use this information to better determine your daily fertility score.