When you are pregnant, you may feel like eating for two, but doubling your daily calorie intake can be a problem. Gaining too much weight during your pregnancy can be harmful to both you and your baby. How much weight is too much weight to gain will vary from woman to woman and pregnancy to pregnancy.

When you are pregnant, you may feel like eating for two, but doubling your daily calorie intake can be a problem. Gaining too much weight during your pregnancy can be harmful to both you and your baby. How much weight is too much weight to gain will vary from woman to woman and pregnancy to pregnancy.

Appropriate Weight Gain Calculations

How much weight gain is appropriate during pregnancy is based on your pre-pregnancy weight and how appropriate your pre-pregnancy weight is for your height. To determine how much weight is too much weight to gain during pregnancy, your health-care provider will take into consideration your body mass index, or BMI. Your body mass index expresses the relationship between your height and your weight. Once your BMI is calculated, a healthy pregnancy weight gain range is determined, based on the Institute of Medicine, of IOM, pregnancy weight gain guidelines. If you've exceeded the highest number in the range, you've gained too much weight.

Weight Gain for Underweight Woman

According to the IOM, women who are underweight before getting pregnant and who have a BMI below 18.5 should gain between 28 and 40 lbs. during their pregnancy. This breaks down to gaining about 1 lb. up to 4.5 pounds during the first trimester of pregnancy and 1 lb. per week during the second and third trimesters. For underweight women, gaining more than 40 lbs. during their pregnancy would be considered too much weight gain.

Weight Gain for Average Women

Women who are considered in the normal weight range prior to getting pregnant–with a BMI of 18.5 to 24.9–should gain between 25 and 45 lbs. during the pregnancy. Average woman should gain between 1 lb. and 4.5 lbs. during the first trimester and 1 lb. per week thereafter. Gaining more than 45 lbs. during the pregnancy would be considered too much weight gain for an average woman. For average women who are carrying twins, more than 54 lbs. of weight gain may be too much.

Weight Gain for Overweight Women

The average recommended weight gain for overweight women is 15 to 25 lbs. For overweight women carrying twins, the maximum suggested weight gain is 50 lbs. Women who are overweight with a BMI of between 25 and 29.9 before conception should gain no more than 25 lbs. during their pregnancy if they are carrying one baby. During the first trimester, overweight women should aim to gain 1 to 4.5 lbs. For the second and third trimesters, overweight women should gain about 8 oz. (half a pound) per week.

Weight Gain for Obese Women

Women with a BMI greater than 30 are considered obese. While the suggested weight gain for obese women is between 11 and 20 lbs., gaining more than 20 lbs. may be considered too much. Obese women should gain between 1 to 4.5 lbs. the first trimester and less than 8 oz. per week for the remainder of their pregnancy. For obese women carrying twins, weight gain should be limited to 42 lbs.

Risks Associated With Too Much Weight Gain

During pregnancy, women who gain too much weight put themselves and their babies at risk for developing complications. Women who gain excessive weight are at in increased risk of delivering their baby early. They are also at risk for having a large baby. Excess weight gain can also cause health problems for the mother. Diabetes and high blood pressure can occur when too much weight is gained during pregnancy.