Preexisting diabetes


  • Plan your pregnancy. Get your diabetes under control 3 to 6 months before you get pregnant.   

  • If untreated, diabetes can cause problems during pregnancy, like premature birth, birth defects and miscarriage.

  • If you have preexisting diabetes, your health care provider sees you more often for prenatal care visits to make sure you and your baby are healthy. 

What is preexisting diabetes?

About 9 out of 100 women (9 percent) in the United States have diabetes. Diabetes is a condition in which your body has too much sugar (called glucose) in the blood. Preexisting diabetes (called type 1 or type 2 diabetes) means you have diabetes before you get pregnant. This is different from gestational diabetes, which is a kind of diabetes that some women get during pregnancy. 

When you eat, your body breaks down sugar and starches from food into glucose to use for energy. Your pancreas (an organ behind your stomach) makes a hormone called insulin that helps your body keep the right amount of glucose in your blood. When you have diabetes, your body doesn’t make enough insulin or can’t use insulin well, so you end up with too much sugar in your blood. This can cause serious health problems, like heart disease, kidney failure and blindness. High blood sugar can be harmful to your baby during the first few weeks of pregnancy when his brain, heart, kidneys and lungs begin to form. It’s really important to get treatment for diabetes to help prevent problems like these. 

Can preexisting diabetes cause problems during pregnancy? 

Yes. If it’s not managed well, diabetes can cause these problems during pregnancy: 

  • Preeclampsia. This is 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. Signs of preeclampsia include having protein in the urine, changes in vision and severe headaches.
  • Premature birth. This is birth before 37 weeks of pregnancy. Premature babies are more likely than full-term babies to have health problems at birth and later in life. 
  • Birth defects, like heart defects and birth defects of the brain and spine called neural tube defects (also called NTDs). Birth defects are health conditions that are present at birth. Birth defects change the shape or function of one or more parts of the body. They can cause problems in overall health, how the body develops, or in how the body works. 
  • Having a very large baby, weighing more than 9 pounds. Weighing this much makes your baby more likely to get hurt during labor and birth. You may need to have a cesarean birth (also called c-section) to keep your baby safe. A c-section is surgery in which your baby is born through a cut that your doctor makes in your belly and uterus (womb). Large babies are more likely to be obese or have diabetes later in life.
  • Miscarriage and stillbirth. Miscarriage is when a baby dies in the womb before 20 weeks of pregnancy. Stillbirth is the death of a baby in the womb after 20 weeks of pregnancy.

If you have diabetes, what can you do before you get pregnant to help you have a healthy pregnancy? 

Plan ahead so you’re as healthy as you can be before you get pregnant. Here’s what you can do:

  • Manage your diabetes even if you’re not planning to get pregnant. If you’re thinking about having a baby, get your diabetes is under control 3 to 6 months before you start trying to get pregnant. Talk to your health care provider, a diabetes educator, a dietitian and other providers about how to manage your diabetes.
  • Use birth control until your diabetes is under control and you’re ready to get pregnant. Birth control is methods you can use to keep from getting pregnant. 
  • Take a multivitamin with 400 micrograms of folic acid in it every day. Folic acid is a vitamin that every cell in your body needs for healthy growth and development. If you take it before pregnancy and during early pregnancy as part of healthy eating, it may help protect your baby from neural tube defects. Because you have diabetes, your provider may want you to take more than 400 micrograms of folic acid each day. 
  • Tell your provider about any medicine you take to make sure it’s OK to take when you do get pregnant. Your provider may want to change some medicines before you get pregnant if they’re not safe for you and your baby. 
  • Eat healthy foods and do something active every day. Talk to a dietitian or a diabetes educator to help you create a healthy meal plan to help control your blood sugar.  
  • Meet with medical specialists who can help you manage your diabetes and any complications that may come up during pregnancy. These doctors include a perinatologist who treats women with high-risk pregnancies and an endocrinologist who treats women with diabetes and other health conditions. 

How is preexisting diabetes treated during pregnancy? 

If you have diabetes, your health care provider wants to see you often during pregnancy so she can monitor you and your baby closely to help prevent problems or catch them before they get serious. 

Blood sugar is affected by pregnancy and by what you eat and drink, how much physical activity you get and your growing baby. What worked for you before pregnancy to control your blood sugar may not work as well when you’re pregnant. Your provider tells you how often to check your blood sugar, what your levels should be and how to manage them during pregnancy. You may need to change what you eat or your physical activity. Or you may need to take insulin shots. If you’re already taking insulin, you may need to take more the longer you’re pregnant. 

Here’s what you can do to help manage your diabetes during pregnancy:

  • Go to all your prenatal care visits, even if you’re feeling fine.
  • Follow your provider’s directions about how often to check your blood sugar. Call your provider if your blood sugar is too high or too low. 
  • Tell your provider about any medicine you take, even medicine that’s not related to your diabetes. Some medicines can be harmful during pregnancy, so your provider may need to change them to ones that are safer for you and your baby. 
  • If you don’t already have a dietician, find one. Your provider can recommend one for you. A dietician can help you learn what, how much and how often to eat to best control your diabetes.  She can help you make meal plans and help you know the right amount of weight to gain during pregnancy. Check to see if your health insurance covers treatment from a dietician. 
  • Do something active every day. With your health provider’s OK, being active every day can help you manage your diabetes. 

What is insulin resistance?

Some pregnant women with diabetes become insulin resistant. This means your body makes insulin but doesn’t use it well. During pregnancy, the placenta grows in your uterus (womb) and supplies food and oxygen to your baby through the umbilical cord. The placenta also makes hormones that help your baby develop. But these hormones can make you insulin resistant. You may need more and more insulin the longer you’re pregnant—up to 3 times as much as you needed before pregnancy. You’re most insulin resistant in your third trimester.

If you have preexisting diabetes, is it OK to breastfeed? 

Yes. If you have diabetes, it’s safe to breastfeed your baby. Breast milk is the best food for your baby during the first year of life. It helps him grow healthy and strong. If you’re thinking about breastfeeding: 

  • Talk to your dietician. She can help create a new meal plan to make sure you get all the calories you need for you and your baby. 
  • Talk to your provider about the amount of insulin you need. You may need less insulin than usual for a few days after giving birth, and breastfeeding can lower the amount even further. It’s safe to take insulin while breastfeeding. 
  • Eat a healthy snack before or after breastfeeding. 
  • Watch your blood sugar closely. You provider may want you to check it more often than usual. 

What are hypoglycemia and hyperglycemia? 

Hypoglycemia is low blood sugar and hyperglycemia is high blood sugar. Both of these conditions are common if you have preexisting diabetes.

Hypoglycemia usually is mild and easily treated by eating or drinking something with sugar in it. If it’s not treated, it can cause you to pass out. Signs and symptoms of hypoglycemia include:  

  • Being hungry
  • Having a headache
  • Feeling weak, dizzy, shaky, confused, worried (anxious) or cranky
  • Looking pale
  • Sweating
  • Having a fast heart beat

Hypoglycemia can be caused by:

  • Not eating enough. This means you may eat meals or snacks that are too small or you may skip or delay eating.  
  • Taking too much insulin 
  • Getting too much physical activity 

If you have hyperglycemia, you may need to change the amount of insulin you take, your meal plan or the amount of physical activity you get. Signs and symptoms of hyperglycemia include:

  • Being thirsty
  • Having a headache
  • Needing to urinate often
  • Felling weak or tired
  • Having trouble paying attention
  • Having blurred vision
  • Having a yeast infection

Your provider can check you for these conditions during pregnancy to make sure you and your baby stay healthy.

Last reviewed: August, 2015