Weight gain during pregnancy

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Key Points

It’s best to start pregnancy at a healthy weight. Talk to your provider to find out a healthy weight for you before you get pregnant.

Gaining too much or too little weight during pregnancy can be harmful to you and your baby.

Don’t ever try to lose weight during pregnancy.

You only need about 300 extra calories a day during pregnancy to support your baby’s growth and development.

Is weight gain important during pregnancy?

Yes. Gaining the right amount of weight during pregnancy can help protect your health and the health of your baby.

If you gain too little weight during pregnancy, you’re more likely than other women to:

  • Have a preterm baby.  A preterm baby is born too early, before 37 weeks of pregnancy.  
  • Have a baby with low birthweight. Low birthweight means your baby is born weighing less than 5 pounds, 8 ounces.

If you gain too much weight during pregnancy, you’re more likely than other women to:

  • Have a preterm baby. Preterm babies may have health problems at birth and later in life, including being overweight or obese. Being obese means you have an excess amount of body fat.
  • Have a baby with fetal macrosomia. This is when your baby is born weighing more than 8 pounds, 13 ounces. Having a baby this large can cause complications, like problems during labor and heavy bleeding after birth.
  • Need a Cesarean birth (also called c-section). This is surgery in which your baby is born through a cut that your health care provider makes in your belly and womb (also called your uterus).
  • Have trouble losing weight after your baby’s birth. This can increase your risk for health conditions like diabetes and high blood pressure.

How much weight should you gain during pregnancy?

Your health care provider uses your body mass index (also called BMI)  before pregnancy to figure out how much weight you should gain during pregnancy. BMI is a measure of body fat based on your height and weight. To find out your BMI, use the CDC's BMI calculator.

If you’re pregnant with one baby or twins, use the following chart to find your recommended weight gain based on your BMI before pregnancy. If you’re pregnant with triplets or more, talk to your provider about the amount of weight you should gain during pregnancy.

Weight gain during pregnancy chart

If you’re overweight or obese and are gaining less than the recommended amounts, talk to your provider. If your baby is still growing well, your weight gain may be fine. 

Gaining weight slowly and steadily is best. Don't worry too much if you don’t gain any weight in the first trimester, or if you gain a little more or a little less than you think you should in any week. You may have some growth spurts—this is when you gain several pounds in a short time and then level off. Don’t ever try to lose weight during pregnancy. 

If you’re worried about your weight gain, talk to your health care provider.

How can you track your weight gain during pregnancy?

Your provider checks your weight at each prenatal care visit. Use our weight-gain tracking chart to track your weight yourself.

Where do you gain the weight during pregnancy?

You know that your growing baby makes up part of the weight you’re gaining. But what about the rest? Here’s a general idea:

  • Baby = 7.5 pounds
  • Amniotic fluid = 2 pounds. Amniotic fluid surrounds the baby in the womb.
  • Blood = 4 pounds
  • Body fluids = 3 pounds
  • Breasts = 2 pounds
  • Fat, protein and other nutrients = 6 to 8 pounds
  • Placenta = 1.5 pounds. The placenta grows in your uterus and supplies the baby with food and oxygen through the umbilical cord.
  • Uterus = 2 pounds. The uterus is the place inside you where your baby grows.

Last reviewed: September 2020