To find out if your weight gain is healthy, enter how many weeks pregnant you are, height, and weight. We'll calculate your BMI during pregnancy, and predict what your weight will be at the end of pregnancy.

Starting pregnancy at a healthy weight is important

A healthy weight gain is essential to ensure both your health and your baby's health. Women who gain too little are at increased risk of having a small baby (less than 5 1/2 pounds). Women who gain too much are at increased risk of having an early baby or a large baby. They may also acquire health problems themselves, such as diabetes, high blood pressure, and varicose veins.

Eating right and moving throughout the pregnancy will help keep pregnancy weight gain even and healthy. There is no reason to diet during pregnancy to stay within pregnancy weight gain limits – it is actually considered dangerous to diet during pregnancy. 

How much weight should you gain?

Pregnancy weight gain is a healthy part of fetal gestation. As the placenta forms, fluid is retained, blood volume increases, and the baby grows. With all of these changes, weight gain is expected. Typical weight gain for a pregnant woman of normal weight is 25 to 35 pounds. Women who are overweight can expect to gain less – 11 to 20 pounds. On the opposite end of the spectrum, women who are underweight should gain between 28 and 40 pounds.

Weight gain should be gradual, as the body needs time to stretch and grow with fetal development. Gaining weight too fast can increase the risk of stretch marks even if the pregnant woman is not genetically predisposed to stretch marks.

How fast should you gain weight during pregnancy?

If you are eating healthy and not overindulging high-calorie foods, weight gain should be gradual. If a sudden increase in weight gain is noted in the final month or so of pregnancy, preeclampsia or gestational diabetes could be the cause. Tests can be run to test for gestational diabetes, but there is no test for preeclampsia so any fast weight gain needs to be reported to the treating obstetrician immediately.

The lowdown on when weight gain begins

During the first trimester, the fetus is so small that you should continue eating as normal. Switching to a healthy diet may actually cause weight loss in expecting women who are overweight or obese when they become pregnant. After the first trimester, things start to change.

Second trimester pregnancy weight gain should be about one pound every week if your BMI before becoming pregnant was less than 24.9. If your BMI measured above 24.9 before pregnancy, you need on ½ pound per week pregnancy weight gain during the second trimester.

Third-trimester pregnancy weight gain should be about the same as second-trimester pregnancy weight gain. Some women find they gain slightly faster during the second trimester, especially if pregnancy weight gain was slow in the second trimester.

Higher weight gain with multiples

If you are pregnant with multiples you can expect a weight gain of 15 pounds more per baby. That means being pregnant with twins can account for 50 pounds of weight gain. Triplets can account for 65 pounds or more.