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Pre-existing diabetes and pregnancy

Pre-existing diabetes and pregnancy

Pregnancy - diabetes; Diabetes and pregnancy care; Pregnancy with diabetes


If you have diabetes, it can affect your pregnancy, your health, and your baby's health. Keeping blood sugar (glucose) levels in a normal range all through your pregnancy can help prevent problems.


This article is for women who already have diabetes and who want to become or are pregnant. Gestational diabetes is high blood sugar that starts or is first diagnosed during pregnancy.

How Diabetes Can Affect You and Your Baby


Women who have diabetes face certain risks during pregnancy. If diabetes is not well-controlled, the baby is exposed to high blood sugar levels in the womb. This can cause birth defects and other health problems in babies.

The first 7 weeks of pregnancy are when a baby's organs develop. This is often before you may know you are pregnant. So it is vital to plan ahead by making sure your blood glucose levels are in the target range before you get pregnant.

While it is scary to think about, it's important to know what problems can occur during pregnancy. Both mom and baby are at risk for complications when diabetes is not well-controlled.

Risks for the baby include:

  • Birth defects
  • Early birth
  • Loss of pregnancy (miscarriage) or stillbirth
  • Large baby (called macrosomia) causes increased risk of injury at the time of birth
  • Low blood sugar after birth
  • Breathing difficulty
  • Jaundice
  • Obesity in childhood and adolescence

Risk for the mother include:

  • An extra-large baby may lead to a difficult delivery or C-section
  • High blood pressure with protein in urine (preeclampsia)
  • Large baby can cause discomfort to the mother and increased risk of injury at the time of birth
  • Worsening of diabetic eye or kidney problems


Before You Get Pregnant


If you are planning a pregnancy, talk to your health care provider at least 6 months before getting pregnant. You should have good blood glucose control at least 3 to 6 months before you get pregnant and all during your pregnancy.

Talk with your provider about what your specific blood sugar goals should be before you get pregnant.

Before getting pregnant, you'll want to:

  • Aim for an A1C level of less than 6.5%
  • Make any changes needed to your diet and exercise habits to support your blood glucose and targets
  • Maintain a healthy weight
  • Schedule a pre-pregnancy exam with your provider and ask about pregnancy care

During your exam, your provider will:

  • Check your hemoglobin A1C
  • Check your thyroid level
  • Take blood and urine samples
  • Talk with you about any diabetes complications such as eye problems or kidney problems or other health problems such as high blood pressure

Your provider will talk with you about what medicines are safe to use and what are not safe to use during pregnancy. Often women with type 2 diabetes who take oral diabetes medicine will need to switch to insulin during pregnancy. Many diabetes medicines may not be safe for the baby. Also, pregnancy hormones can block insulin from working normally in the body (insulin resistance), so many diabetes medicines don't work as well.

You should also see your eye doctor and have a diabetic eye exam.


Pregnancy and Prenatal Care


During your pregnancy, you will work with a health care team to make sure you and your baby remain healthy. Because your pregnancy is considered high-risk, you will work with an obstetrician who specializes in high-risk pregnancies (maternal-fetal medicine specialist). This provider may do tests to check your baby's health. The tests may be done at any time while you are pregnant. You will also work with a diabetes educator and dietician.

During pregnancy, as your body changes and your baby grows, your blood glucose levels will change. Being pregnant also makes it hard to notice symptoms of low blood sugar. So you will need to monitor your blood sugar as often as 8 times a day to make sure you stay in your target range. You may be asked to use continuous glucose monitoring (CGM) during this time.

Here are common target blood sugar goals during pregnancy:

  • Fasting: Less than 95 mg/dL
  • One hour after a meal: less than 140 mg/dL, OR
  • Two hours after a meal: less than 120 mg/dL

Ask your provider what your specific target range should be and how often to test your blood sugar.

You will need to work with your dietician to manage what you eat during pregnancy to help you avoid low or high blood sugar. Your dietician will also monitor your weight gain.

Pregnant women need about 300 extra calories a day. But where these calories come from matters. For a balanced diet, you need to eat a variety of healthy foods. In general, you should eat:

  • Plenty of whole fruits and vegetables
  • Moderate amounts of lean proteins and healthy fats
  • Moderate amounts of whole grains, such as bread, cereal, pasta, and rice, plus starchy vegetables, such as corn and peas
  • Fewer foods that have a lot of sugar, such as soft drinks, fruit juices, and pastries

You should eat three small- to moderate-sized meals and one or more snacks each day. Do not skip meals and snacks. Keep the amount and types of food (carbohydrates, fats, and proteins) the same from day to day. This can help you keep your blood sugar stable.

Your provider may also suggest a safe exercise plan. Walking is usually the easiest type of exercise, but swimming or other low-impact exercises can work just as well. Exercise can help you keep your blood sugar in control.


Labor and Delivery


Labor may start naturally or may be induced. Your provider may suggest a C-section if the baby is large. Your provider will check your blood sugar levels during and after delivery.

Your baby is more likely to have periods of low blood sugar (hypoglycemia) during the first few days of life and may need to be monitored in a neonatal intensive care unit (NICU) for a few days.

Once you arrive home, you will need to continue to closely watch your blood sugar levels. Lack of sleep, changing eating schedules, and breastfeeding can all affect blood sugar levels. So while you need to care for your baby, it's just as important to care for yourself.


When to Call the Doctor


If your pregnancy is unplanned, contact your provider right away.

Call your provider for the following diabetes-related problems:

  • If you can't keep your blood sugar in the target range
  • Your baby seems to be moving less in your belly
  • You have blurred vision
  • You are more thirsty than normal
  • You have nausea and vomiting that won't go away

It's normal to feel stressed or down about being pregnant and having diabetes. But, if these emotions are overwhelming you, call your provider. Your health care team is there to help you.




American Diabetes Association. 14. Management of diabetes in pregnancy: Standards of Medical Care in Diabetes-2021. Diabetes Care. 2021;44(Suppl 1):S200-S210. PMID: 33298425

Centers for Disease Control and Prevention website. Type 1 or type 2 diabetes and pregnancy. Updated July 6, 2021. Accessed July 14, 2020.

Landon MB, Catalano PM, Gabbe SG. Diabetes mellitus complicating pregnancy. In: Landon MB, Galan HL, Jauniaux ERM, et al, eds. Gabbe's Obstetrics: Normal and Problem Pregnancies. 8th ed. Philadelphia, PA: Elsevier; 2021:chap 45.

The National Institute of Diabetes and Digestive and Kidney Diseases website. Pregnancy if you have diabetes. Updated January 2017. Accessed July 6, 2020.

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        Review Date: 5/13/2021

        Reviewed By: Brent Wisse, MD, Board Certified in Metabolism/Endocrinology, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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