Being overweight during pregnancy

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Key Points

Being overweight or obese during pregnancy can cause problems for you and your baby.

Get to a healthy weight before you get pregnant. Talk to your health care provider about the right weight for you.

Talk to your provider about how much weight to gain during pregnancy.

Don’t ever try to lose weight during pregnancy.

Talk your provider about how you can stay healthy during pregnancy if you are overweight or obese.

How do you know if you’re overweight or obese?

Being overweight during pregnancy can cause complications for you and your baby. The more overweight you are, the more likely you are to have pregnancy complications. But there are things you can do before and during pregnancy to help you have a healthy baby.

Being overweight is based on your pre-pregnancy body mass index (also called BMI). Pre-pregnancy means your BMI before you get pregnant. BMI is a calculation based on your height and weight:

  • If you’re overweight, your BMI is 25.0 to 29.9 before pregnancy. Overweight means you have excess body weight that comes from your muscles, bone, fat and water. About 3 in 4 women (75 percent) in the United States are overweight.
  • If you’re obese, your BMI is 30.0 or higher before pregnancy. Obese means you have an excess amount of body fat. About 4 out of 10 women ages 20-39 (40 percent) in the United States is obese.

To find out your BMI, use this BMI calculator or talk to your health care provider.

What kinds of pregnancy complications can being overweight or obese cause?

Before pregnancy, if you’re overweight or obese you’re more likely than women at a healthy weight to have problems getting pregnant (also called infertility). Obesity can affect a certain kind of fertility treatment called in vitro fertilization (also called IVF). IVF is when an egg and sperm are combined in a lab to create an embryo (fertilized egg) which is then put into your uterus. The higher your BMI, the less likely it is for you to get pregnant with IVF.

You may also have some problems with testing like during your ultrasounds. An ultrasound is a prenatal test that uses sound waves and a computer screen to show a picture of your baby in the womb. Having too much body fat can make it difficult to see your baby by ultrasound. Checking your baby’s heart rate during labor may also be more difficult if you’re obese. 

If you’re overweight or obese during pregnancy, you’re more likely to have these complications:

  • High blood pressure, preeclampsia and blood clotting problems. High blood pressure is when the force of blood against the walls of the blood vessels is too high. Preeclampsia is a condition that can happen after the 20th week of pregnancy or right after pregnancy. It’s when a pregnant woman has high blood pressure and signs that some of her organs, like her kidneys and liver, may not be working properly. Clotting problems are when blood clots partly or completely block the flow of blood in a blood vessel.
  • Gestational diabetes. This is a kind of diabetes that some women get during pregnancy. Diabetes is when your body has too much sugar (called glucose) in the blood. Having this during pregnancy puts you at higher risk of having diabetes after you have your baby. You’re also at risk for a milder form called insulin resistance. 
  • Being pregnant past your due date and problems during labor and birth, including problems with anesthesia (pain medicine). You also may need to stay in the hospital longer after having your baby than women at a healthier weight.
  • Cesarean birth (also called c-section). This is surgery in which your baby is born through a cut that your doctor makes in your belly and uterus (womb). If you’re obese, you’re more likely to have complications from a c-section, like an infection or losing too much blood.  
  • Miscarriage or stillbirth. Miscarriage is when a baby dies in the womb before 20 weeks of pregnancy. Stillbirth is when a baby dies in the womb before birth but after 20 weeks of pregnancy.
  • Trouble losing your pregnancy weight after giving birth

If you’re obese, you’re more likely to have other complications, including:

  • Infections during pregnancy, like urinary tract infections
  • A sleep disorder called obstructive sleep apnea. This is when your breathing stops while you’re sleeping.
  • A dangerous blood clot problem called venous thromboembolism (also called VTE). This is when a blood clot breaks off and travels through your blood to organs like the brain, lungs or heart. This can cause a stroke or heart attack.
  • Needing to go to the hospital earlier in labor, having longer labor and needing to have your labor induced. Inducing labor is when your provider gives you medicine or breaks your water (amniotic sac or bag of waters) to make your labor begin.
  • Problems with breastfeeding.
  • During labor, too much body fat may also block the passage of your baby through the pelvis. 

Can being overweight or obese cause problems for your baby?

Yes. If you’re overweight or obese during pregnancy, your baby is more likely to have these conditions:

  • Preterm birth. This is birth that happens before 37 completed weeks of pregnancy. This is too soon and can cause serious health problems for your baby.
  • Birth defects, including neural tube defects (also called NTDs), and heart defects. NTDs are birth defects of the brain and spine. A birth defect is a health condition that a baby has at birth. Birth defects change the shape or function of one or more parts of the body. They can cause problems in overall health, in how the body develops, or in how the body works. It may be hard for your health care provider to diagnose birth defects during pregnancy even prenatal tests like ultrasound.
  • Macrosomia (also called large for gestational age or LGA). This means your baby weighs more than 8 pounds, 13 ounces at birth. When a baby is this large, it can cause complications during labor and birth, including injury to your baby. It also increases your chances of needing a c-section, Type 2 diabetes, heart disease, asthma and obesity later in life
  • If you have gestational diabetes, your baby may have problems with breathing, low glucose levels and jaundice. Jaundice is when skin or the white in a person’s eyes look yellow.

What can you do to improve your chances of having a healthy pregnancy and a healthy baby?

Before pregnancy, get a preconception checkup. This is a medical checkup you get before pregnancy. Your health care provider can help you find ways to eat healthy and be physically active to help you lose weight before you get pregnant. Losing weight before pregnancy is good for both you and your baby. If you’re thinking about weight-loss surgery, talk to your provider about your options and how long to wait after the surgery before you get pregnant.

During pregnancy, do these things to help keep you and your baby healthy:

  • Get early and regular prenatal care. Prenatal care is medical care you get during pregnancy. Go to every prenatal care checkup, even if you’re feeling fine. Your provider gives you prenatal tests, like a glucose screening test for diabetes and ultrasound to get a picture of your baby in the womb. 
  • Talk to your provider about how much weight to gain during pregnancy. If you’re overweight, you want to gain about 15 to 25 pounds during pregnancy. If you’re obese, your target range is 11 to 20 pounds. These numbers are greater if you are having multiples like twins.
  • Eat healthy foods. Talk to your provider or a nutritionist to help you plan your meals. Check out from the U.S. Department of Agriculture. It can help you make a healthy eating plan based on your age, weight, height and physical activity. It also has a special section just for pregnant women.
  • Don’t diet. Some diets can reduce the nutrients your baby needs to grow and develop. Don’t try to stay at the same weight or lose weight during pregnancy.
  • Do something active every day. Talk to your provider about activities that are safe for you.
  • Talk to your provider about how you can be monitored more closely during pregnancy if you’re overweight or obese. This can include making changes to ultrasound tests and screening for sleep apnea. 

Last reviewed: March 2020