Pregestational diabetes mellitus is diabetes that was present before pregnancy. When diabetes starts during pregnancy, it is called gestational diabetes mellitus. Both types of diabetes need special care during pregnancy.

This pamphlet explains

pregestational and gestational diabetes effects of diabetes on pregnancy how to control diabetes during pregnancy delivery and postpartum care

All types of diabetes are a concern in pregnancy. Glucose control, a healthy diet, exercise, and medications, if needed, are keys to a healthy pregnancy.

Pregestational Diabetes

About 1 in 100 women have pregestational diabetes. Diabetes is caused by a problem with insulin. Insulin moves glucose out of the blood and into the body’s cells where it can be turned into energy. When the body does not make enough insulin or does not respond to it, glucose cannot get into cells and instead stays in the blood. High levels of glucose in the blood is called hyperglycemia. Over time, high blood glucose levels can damage the body and cause many problems, like heart disease, eye problems (including blindness), and kidney disease.

Types of Diabetes

For a woman with existing diabetes, seeing a health care provider before becoming pregnant is very important.

There are two types of diabetes: type 1 and type 2. In type 1 diabetes, the body makes little or no insulin on its own. This type of diabetes tends to occur early in life. In type 2 diabetes, insulin is produced, but the body does not respond to it. More insulin is produced to keep glucose levels normal. This type of diabetes tends to occur later in life. Major risk factors for type 2 diabetes are obesity and family history.

Women with diabetes need to regularly check and control their blood glucose levels. Type 1 diabetes is treated with insulin. A healthy diet and regular exercise also help keep blood glucose levels under control. Type 2 diabetes often can be managed with a program of weight loss, diet, and exercise to maintain an ideal body weight. Oral medication or insulin sometimes may be needed.

Effects During Pregnancy

If a woman has medical conditions caused by her diabetes, pregnancy can make these conditions worse. Miscarriage and stillbirth are more common in pregnant women with diabetes. The risk of the following problems also is increased:

• Hydramnios—This condition can lead to preterm labor and delivery.
• Preeclampsia—This condition is linked to high blood pressure. Preeclampsia can lead to seizures or kidney or liver problems in the mother. The baby may need to be delivered early.
• Respiratory distress syndrome (RDS)—This syndrome can make it harder for the baby to breathe after birth.
• Birth defects—Birth defects, most often involving the heart, brain, and skeleton, can occur. These defects have been linked to high blood glucose levels in the mother early in pregnancy, when the baby’s organs were developing.
• Macrosomia (very large baby)—When the mother’s glucose level is high throughout pregnancy, the baby can receive too much glucose. As a result, the baby can grow too large. A large baby may make vaginal delivery difficult.

• diagnosis and treatment of any medical conditions caused by her diabetes
• meal plans and exercise advice, including information about folic acid to prevent neural tube defects
• information about maintaining a healthy weight during pregnancy

Gestational Diabetes

Pregnancy changes the way insulin works. Some women develop gestational diabetes as a result of this change. Gestational diabetes is thought to affect 2–10% of all pregnancies.

Several risk factors are linked to gestational diabetes. It also occurs in women who have no risk factors. But it is more likely in women who

• are older than 25 years
• are overweight
• have had gestational diabetes before
• have had a very large baby
• have a close relative with diabetes
• had problems in a previous pregnancy (such as stillbirth)
• are Native American, Asian, Hispanic, African American, or Pacific Islander
• have polycystic ovary syndrome

Effects During Pregnancy

In women with gestational diabetes, high blood glucose levels during pregnancy increase the risk of having a very large baby and possible cesarean birth. Preeclampsia also is more common in women with gestational diabetes.

Effects After Pregnancy

One third of women who had gestational diabetes during pregnancy have diabetes or a milder form called glucose intolerance after giving birth. Up to one half will develop type 2 diabetes later in life. Women who have had gestational diabetes should get regular tests for diabetes after pregnancy (see “"Postpartum Care”).

Diabetes Control

Testing for Diabetes If you have risk factors for gestational diabetes, your blood glucose level is measured early in pregnancy. If you do not have risk factors, you may be tested between 24 and 28 weeks of pregnancy. The test is safe and simple. First, you drink a liquid that has sugar in it. Next, samples of your blood are taken. The glucose level is measured. If the level is high, more tests are done to find out if you have diabetes.

Both kinds of diabetes must be controlled during pregnancy. Doing so requires daily tracking of glucose levels, eating healthy foods, exercising regularly, and taking medication, if needed. Prenatal care also is important. Whether you have gestational diabetes or existing diabetes, you will see your health care provider more often while you are pregnant.

Tracking Glucose Levels

Women with gestational diabetes should check their blood glucose levels at least daily. Women with pregestational diabetes will need to check their glucose levels more often. A glucose meter tests a small drop of blood. The drop of blood is placed on a strip of special paper. The glucose level then is read with the meter.

Checking your glucose level is an important part of keeping it within the normal range. For the best results, follow the schedule your doctor gives you. Keep accurate notes and report your levels to your doctor at each prenatal visit.

Healthy Eating

A balanced diet is a key part of any pregnancy. Your baby depends on the food you eat for its growth and nourishment. Diet is even more important if you have diabetes—as important as medication. Not eating properly can cause glucose levels to go too high or too low.

The number of calories you need depends on your weight, stage of pregnancy, age, and level of activity. In most cases, the diet will include special meals. Meals and snacks will be spread throughout the day and before bedtime. You may be asked to keep a log of what you eat. Changes may be made to improve glucose control or to meet the needs of the growing baby.

Exercise

For all pregnant women, but especially those with diabetes, exercise is important. Exercise helps keep glucose levels in the normal range. You and your health care provider will decide how much and what type of exercise you need. Usually, 30 minutes of exercise per day are recommended.

Medications

Women with pregestational diabetes who took insulin before pregnancy usually need to increase their insulin dosage while they are pregnant. Insulin is safe to use during pregnancy. Because the amount of insulin needed throughout the day varies throughout pregnancy, your insulin dosage may need to change. If you manage your diabetes with oral medications, you may need insulin during pregnancy.

Mild gestational diabetes often can be controlled with a special diet and exercise. Some women with gestational diabetes need oral medications or insulin to keep levels normal.

Prenatal Care

Prenatal care helps monitor your health as well as that of your baby. A team of health care experts may help care for you during pregnancy. A dietician may help with meal plans.

A woman with diabetes may need special tests in addition to routine health care. These tests can help your health care provider be aware of any problems and take steps to correct them. Some of the following tests may be done:

1. Kick count—This is a record of how often you feel your baby move. A healthy baby tends to move the same amount each day. You may be asked to keep track of this movement late in pregnancy. You will be told to contact your doctor if the baby is not active.
2. Ultrasound exam—This exam checks how the baby is developing and whether any birth defects are apparent. Later in pregnancy, it is used to help estimate fetal weight, locate the placenta, and assess the level of amniotic fluid.
3. Fetal heart rate monitoring—The baby’s heart rate is measured with a monitor that is placed on the mother’s abdomen.
4. Biophysical profile—This ultrasound test checks fetal breathing, fetal body movement, fetal muscle tone, and the amount of amniotic fluid. It may include other tests. Results of these tests can give detailed information about the baby’s health.

Delivery

Most women with diabetes are able to have a vaginal birth but are more likely to have a cesarean birth than women without diabetes. Labor also may be induced (started by drugs or other means) earlier than the due date if problems with the pregnancy arise. Women with diabetes will need tracking of their glucose levels and close monitoring of the baby during labor.

After birth, most babies of women with good glucose control do well. Some may need to spend time in a special care nursery. Problems can include

• low glucose levels
• low calcium and magnesium levels in the blood
• jaundice (yellow color of the skin)
• breathing problems

Postpartum Care

If you had gestational diabetes, you should have a test for diabetes 6–12 weeks after you give birth. Even if the result is normal, you are more likely to develop type 2 diabetes later in life. The American Diabetes Association recommends that women who have had gestational diabetes and who had a normal postpartum glucose test result be tested for diabetes every 3 years. Be sure to tell any health care providers whom you see that you have had gestational diabetes.

If you have pregestational diabetes, you will be able to go back to your pre-pregnancy insulin dosage very soon after birth. If you breast-feed, you will need to eat extra calories. Talk to your health care provider about the amount and types of foods that you should eat to get these extra calories.

Finally...

All types of diabetes are a concern in pregnancy. Glucose control, a healthy diet, exercise, and medications, if needed, are the keys to a healthy pregnancy. Close monitoring of glucose levels is important. If you have existing diabetes, seeing a health care provider and controlling glucose levels before you become pregnant can decrease the risks to both you and your baby. Women with gestational diabetes will need follow-up tests for diabetes beginning at their first postpartum visit.

Glossary

Amniotic Fluid: Water in the sac surrounding the fetus in the woman’s uterus.

Biophysical Profile: An assessment by ultrasound of fetal breathing, fetal body movement, fetal muscle tone, and the amount of amniotic fluid. May include fetal heart rate. Sometimes the profile includes only the nonstress test and an estimate of the amount of amniotic fluid.

Cesarean Birth: Delivery of a baby through an incision made in the mother’s abdomen and uterus.

Insulin: A hormone that lowers the levels of glucose (sugar) in the blood.

Hydramnios: A condition in which there is an excess amount of amniotic fluid surrounding the fetus.

Miscarriage: Early pregnancy loss.

Neural Tube Defect: A birth defect that results from incomplete development of the brain, spinal cord, and their coverings.

Obesity: A condition characterized by excessive body fat.

Placenta: Tissue that provides nourishment to and takes away waste from the fetus.

Polycystic Ovary Syndrome: A condition in which increased androgen levels occur and eggs are not released from the ovaries.

Preeclampsia: A condition of pregnancy in which there is high blood pressure and protein in the urine.

Preterm: Born before 37 weeks of pregnancy.

Respiratory Distress Syndrome (RDS): A condition of some babies in which the lungs are not mature, causing breathing difficulties.

Stillbirth: Delivery of a baby that shows no sign of life.

Ultrasound: A test in which sound waves are used to examine internal structures. During pregnancy, it can be used to examine the fetus.

This Patient Education Pamphlet was developed by the American College of Obstetricians and Gynecologists. Designed as an aid to patients, it sets forth current information and opinions on subjects related to women’s health. The average readability level of the series, based on the Fry formula, is grade 6–8. The Suitability Assessment of Materials (SAM) instrument rates the pamphlets as “superior.” To ensure the information is current and accurate, the pamphlets are reviewed every 18 months. The information in this pamphlet does not dictate an exclusive course of treatment or procedure to be followed and should not be construed as excluding other acceptable methods of practice. Variations, taking into account the needs of the individual patient, resources, and limitations unique to the institution or type of practice, may be appropriate.

Copyright © June 2009 by the American College of Obstetricians and Gynecologists. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, posted on the Internet, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher.

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