BMI and its weight recommendations during pregnancy


Weight measures the body fat, height and the muscularity by using a formula to produce a measure known as BMI or body mass index. A body mass index that is below 18 is considered thin and one that is beyond 30, obese. BMI = weight in kilo / (height in metres)²


For singleton pregnancy and a woman with normal prepregnancy weight, her BMI reading will be 18.5 – 25 kg/m². In the first trimester she should gain 4-6 lbs, in the second trimester the gain should be 10-14 lbs and in the last trimester the gain should be 10-15 lbs. The total recommended weight gain should be 25-35lbs (11-16kg).


For a singleton pregnancy and a woman who is underweight before pregnancy, the BMI reading will be below 18.5kg/m². In the first trimester the weight gain should be 4-6lbs, in the middle trimester the gain should be 14-20lbs and 10-14lbs in the last trimester. Overall weight gain should fall in the range of 28-40lbs (13-18kg)


For a singleton pregnancy and a woman who is overweight before pregnancy, her BMI reading will be 25-30kg/m². In the first trimester her weight gain should be 2-4lb, in the second trimester the gain should be 8-13lb and in the last trimester the gain should be 5-8lb. The total recommended weight gain should not exceed 25 pounds (11kg)