For a woman with prepregnancy BMI of 22, total pregnancy weight gain should fall within the range of 25 to 35 pounds. The BMI is an abbreviation for the body mass index that is defined as the body mass divided by the square of the body height. It is expressed in kg/m², resulting from mass in kilograms and height in meters. A BMI of 18.5 to 24.9 is considered healthy, while that of 25 to 29.9 is considered overweight and the one over 30 is considered obese.
