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Pregnant women need a proper diet and weight for optimal health and for the nourishment of a growing baby. If a woman doesn't gain enough weight during pregnancy, her baby is at risk of being born small and having health problems. A woman who gains too much weight during pregnancy risks having a large baby and complications during pregnancy and childbirth. She could also have great difficulty losing the weight after birth.

How Much Weight Should I Gain?

The amount of weight you should gain during pregnancy depends upon several factors including your prepregnancy weight and your age. If you are of average weight for your height, you are encouraged to gain between 25-35 pounds. If you are underweight or have a low body mass index (BMI), you will need to gain a bit more weight than a pregnant woman with average weight. If you are overweight, you will need to gain a little less weight than a pregnant woman with average weight.

Women who are less than 5'2" tall should try to gain on the lower end of the weight spectrum, as greater weight gain tends to increase their risk of problems during delivery. Teens and women who are pregnant with twins or multiples are encouraged to gain slightly more weight than average.

A slow and steady weight gain over the nine month period is best, but keep in mind that women gain weight at different rates. You should never try to lose weight during pregnancy, even if you are overweight. The burning of fat stores during pregnancy could cause your body to release substances that could harm your baby. Your doctor will suggest a weight range than best suits you, given your particular needs.

The following chart is an estimate of how much weight you should gain per trimester based on your normal weight, age, and whether you are carrying one fetus, twins, or triplets.

Approximate Pregnancy Weight Gain in Pounds

Pregnancy Status 1st Trimester
Weight Gain
2nd Trimester
Weight Gain
3rd Trimester
Weight Gain
Total Weight Gain
Underweight Adult2-5 lbs.13-20 lbs.13-15 lbs.28-40 lbs.
Normal Weight Adult2-4 lbs.13-18 lbs.10-13 lbs.25-35 lbs.
Overweight Adult0.5-1 lb.7.5-14 lbs.7-10 lbs.15-25 lbs.
Underweight Teen4-5 lbs.17-20 lbs.14-15 lbs.35-40 lbs.
Normal Weight Teen3-5 lbs.15-20 lbs13-20 lbs.28-40 lbs.
Overweight Teen1-3 lbs.10-12 lbs.7-10 lbs.18-25 lbs.
Underweight With Twins4-6 lbs.19-23 lbs.17-21 lbs.40-50 lbs.
Normal to Overweight With Twins3-4 lbs.19-22 lbs.13-19 lbs.35-45 lbs.
Triplets4-5 lbs.30+ lbs.11-15 lbs.45+ lbs.

Oh No! Do I Have to Get Fat?

Many women fear the inevitable weight gain of pregnancy, even though it's normal and healthy. The important thing to keep in mind is that, for the majority of women, most of the weight gained is not fat. The following table illustrates how an average weight gain is distributed in pregnancy:

Approximate Distribution of Weight Gain in Average Pregnancy

Baby7.5 lbs
Uterus2.0 lbs
Placenta1.5 lbs
Blood volume increase in mother2.75 lbs
Amniotic fluid1.75 lbs
Fluids in mother's tissues3.0 lbs
Breast tissue increase1.0 lbs
Increased fat stores in mother7.0 lbs
Total Average26.5 lbs

How Should I Gain Weight?

You should add an average of 200 calories more per day to your diet. These calories, as well as most of the calories in your diet, should not come from junk food that is full of fat and sugar. Junk foods have few nutrients and are considered "empty calories." Nutritious snack ideas include fresh fruit, crackers and cheese, peanut butter, and whole grain breads and cereals. You may notice that you gain weight slowly during the first trimester. This is quite normal. During the second and third trimester, you will gain the bulk of your weight.

A new MyPyramid website, based on the USDA’s 2005 dietary guidelines, was recently released for pregnant or nursing women. The interactive site allows you to get a personalized food plan, helping you to choose from a variety of fruits, vegetables, whole grains, lean protein, dairy foods, and healthful fats.

What Will Happen to My Weight After Birth?

Your postpartum weight will, in part, be affected by how much weight you gained during pregnancy. If you gain too much weight during pregnancy or develop poor eating habits and a sedentary lifestyle, you may have more difficulty losing the weight after the baby is born. The following factors help women to lose weight more quickly after giving birth:

  • Eating a healthful, well-balanced diet that is low in fat, high in fiber, and rich in nutrients
  • Breastfeeding
  • Exercising four or more times a week for at least 30 minutes (regular aerobic exercises that involve the large muscles and elevate the heart rate are best for burning calories)

The most important thing to keep in mind is that you are growing a baby, and therefore must have extra calories and weight during pregnancy. Choose your calories wisely by eating nutritious foods.