Does being overweight affect pregnancy?


  • 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 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.

Calculate your body mass index (also called BMI) using your pre-pregnancy weight, to know if you are overweight. 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  (39.7 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). 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. 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.
  • Gestational diabetes. This is a kind of diabetes that some women get during pregnancy. Having gestational diabetes puts you at higher risk of having diabetes after you have your baby and of having insulin resistance. Insulin resistance happens when the insulin in your body can’t lower the sugar in your blood the way it should.
  • 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). 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.
  • 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.
  • 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:
  • Premature birth.
  • Birth defects.  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 to 9 pounds, 14 ounces at birth. This can cause complications during labor and birth, including injury to your baby.
  • 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.  

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

Before pregnancy, get a preconception checkup. Your provider or a registered dietitian can help you make a plan to lose weight before you get pregnant.

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

  • Get early and regular prenatal care. 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 registered dietitian to help you plan your meals. Check out to help you make a healthy eating plan based on your age, weight, height and physical activity. It has a special section for pregnant women.
  • Don’t diet. 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 daily. 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.  



save print