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Gestational Diabetes


  • Gestational diabetes is the first metabolic disorder found or found during pregnancy and should be distinguished from diabetes before pregnancy.
  • Pregnancy age, multiple pregnancies, maternal fertility, obesity before pregnancy, and family history of type 2 diabetes are risk factors for gestational diabetes.
  • Gestational diabetes is caused by increased insulin resistance and relatively insufficient insulin secretion due to hormonal changes and increased body fat in the second half of pregnancy.

1. Definitions of gestational diabetes

1) Gestational diabetes: Glucose metabolism disorder that first occurred or was found during pregnancy (usually mid to late pregnancy).

2) Pre-pregnancy diabetes: If a woman with diabetes before pregnancy is pregnant, diabetes that is found during the first prenatal visit is defined as pre-pregnancy diabetes, not gestational diabetes.

3) Some women do not know if they had diabetes before pregnancy but are diagnosed with diabetes through regular examinations during pregnancy.

4) Most gestational diabetes begins during pregnancy and disappears with childbirth. However, because the causes of gestational diabetes are similar to those of diabetes, it often progresses gradually after delivery.

5) Because gestational diabetes develops during the second half of pregnancy, it is not related to the risk of birth defects or miscarriage, as in the case of diabetic women who are pregnant without blood sugar control. However, even with pre-pregnancy diabetes, good blood sugar control before and during pregnancy reduces the risk of malformations or miscarriage.

2. Causes and risk factors for gestational diabetes

1) Old age

2) Multiple pregnancy

3) Obesity before pregnancy

4) High blood pressure during pregnancy

5) Birth history of giant children (4 kg or more)

6) Polycystic ovary syndrome

7) Saturated Fat Meal

8) Multiple birth history

9) Family history of type 2 diabetes

10) History of prediabetes, such as impaired ability to control blood glucose or impaired fasting glucose

11) Gestational diabetes from previous pregnancy

12) History of stillbirth or birth defects

3. Pathophysiology

1) In the middle and late gestation, insulin resistance normally increases, which means that the effect of insulin action is reduced. In late pregnancy, insulin action is reduced by 50-70% from pre-pregnancy, increasing insulin requirements two to three times higher than before pregnancy.

2) Insulin resistance is associated with changes in hormone concentrations such as lacrimal stimulating hormone, cortisol, progesterone, and prolactin produced in the placenta during pregnancy, and increases in body fat during pregnancy.

3) Normally, the pancreas releases more insulin to meet increasing insulin demands in pregnancy, so your ability to control blood sugar is not bad. However, pregnant women with gestational diabetes do not have sufficient insulin secretions. As a result, blood sugar rises.

Epidemiology and Statistics

  • The incidence of gestational diabetes is steadily increasing by one to two percent each year.
  • In gestational diabetes, there is a 50% chance of recurrence in the next pregnancy.

1. Prevalence of gestational diabetes

1) Frequency of occurrence varies between countries and ethnicities, and is reported around 5-10% worldwide.

2) The prevalence of gestational diabetes increases with age. According to the 2011 statistics, the prevalence of gestational diabetes is estimated to be 12.5%, the highest among 40-44 years, and the prevalence of relatively young women in their 30s and 20s increases every year.

2. Risk of gestational diabetes

1) Obstetric complications that can occur if you do not receive proper treatment during pregnancy include hyperamniotic fluid, gestational hypertension (pregnancy intoxication), pyelonephritis, premature birth, and complications during surgical delivery.

2) Problems that can occur in newborns include megaloids (4 kg or more), birth damage, hypoglycemia, hypocalcemia, hyperbilirubinemia, hypererythrocytes, and neonatal respiratory distress.

3) Perinatal mortality rate was 1.5% in normal pregnant women, while perinatal mortality in pregnant women with poor blood sugar control was reported at 6.4%. In recent years, screening tests for gestational diabetes have been carried out in almost all pregnant women, which leads to active blood sugar management, and the perinatal mortality rate is no different from normal pregnant women.

4) Women who have had gestational diabetes are estimated to have about 50% higher risk of recurrence of gestational diabetes during their next pregnancy.

5) Patients with gestational diabetes are at high risk of developing postpartum diabetes. About 5% after delivery, about 35% go to type 2 diabetes in about 50% within 20 years.

6) Newborn babies born with maternal gestational diabetes are at increased risk of developing obesity and type 2 diabetes in childhood and adulthood.


  • Diagnosis of gestational diabetes is done between 24 and 28 weeks of gestation, and there are two stages of the test, one with a two-stage approach (diagnosis if the screening test is positive).
  • The level of glycemic control during pregnancy is evaluated by measuring self-blood glucose, ketoneuria, and glycated hemoglobin.
  • A 75g oral glucose load test is performed 4 to 12 weeks after delivery to check for continued diabetes.

1. Diagnosis of gestational diabetes

1) One step approach
You should be diagnosed with gestational diabetes if at least 8 hours of fasting between 24 to 28 weeks of pregnancy or overnight fasting, 75g of sugar in the morning, and then blood glucose measurements if one or more of the following criteria are true:

  • Fasting plasma glucose โ‰ฅ 92 mg / dL
  • Plasma blood glucose โ‰ฅ 180 mg / dL after 1 hour of glucose load
  • Plasma blood glucose โ‰ฅ 153 mg / dL after 2 hours of glucose load

2) Two step approach

(1) Stage 1 (screening): Drinking 50g of sugar between 24 and 28 weeks gestation, at least 50 mg of sugar and after 1 hour plasma glucose concentration of 140 mg / dL (130 mg / dL for high-risk mothers) If positive, a 100g oral glucose load test is performed.

(2) Stage 2 (diagnostic test): After fasting for at least 8 hours or overnight fasting, drink 100g of sugar in the morning, and then measure the blood sugar to diagnose gestational diabetes if two or more of the following criteria are met.

  • Fasting plasma glucose โ‰ฅ 95 mg / dL
  • Plasma blood glucose โ‰ฅ 180 mg / dL after 1 hour of glucose load
  • Plasma blood glucose โ‰ฅ 155 mg / dL after 2 hours of glucose load
  • Plasma blood glucose โ‰ฅ 140 mg / dL after 3 hours of glucose load

2. Examination during pregnancy after diagnosis

1) Self blood glucose measurement is usually performed 4 to 7 times a day (fasting, after 1 hour or 2 hours after each meal, before bedtime). If the blood glucose control goal is well achieved, the frequency of blood glucose measurement can be reduced. Postprandial blood sugar makes it easy to see how the type and amount of food you eat affects blood sugar changes. If fasting blood sugar is high for unknown reasons, you may need to take blood glucose measurements around 2 to 3 am.

2) A ketone test is useful as a way to evaluate whether you have enough calories and carbohydrates in your diet during pregnancy.You should do it when you are sick, nausea, or vomiting and eat less food than usual, and tell your doctor if you are positive. .

3) The glycated hemoglobin test is an indicator that reflects the level of blood sugar in the recent 2-3 months.

3. Examination after delivery

1) In the case of gestational diabetes, most of the blood sugar returns to normal immediately after delivery. However, since it may be type 1 or type 2 diabetes that was not diagnosed before pregnancy, 75g oral glucose load test should be performed 4 to 12 weeks after delivery. General blood glucose standards for non-pregnancy are used to determine whether diabetes is ongoing or prediabetes.

2) Even if the test is normal at this time, if there is gestational diabetes, the risk of developing type 2 diabetes is very high, so periodic follow-up tests are necessary.


  • Thorough blood sugar control can reduce perinatal complications and obstetric complications.
  • If diet and exercise make it difficult to reach your target blood sugar, insulin treatment should be given. In general, insulin therapy is recommended, but you may consider using metformin or glyburide if you are unable to use insulin or if you refuse to treat insulin.
  • In most cases, in gestational diabetes mothers, blood sugar is normalized after delivery.

1. The goal of treatments

  • Fasting blood glucose โ‰ค 95 mg / dL, and
  • 1 hour postprandial blood sugar โ‰ค 140 mg / dL, or 2 hours postprandial blood sugar โ‰ค 120 mg / dL
  • If it is difficult to reach your treatment goals without hypoglycemia, then relax your treatment goals so that they are tailored to your situation. Self-glucometers are very important in managing diabetes during pregnancy and place more emphasis on postprandial blood sugar control than fasting or pre-prandial blood sugar.
  • During pregnancy, red blood cell replacement rate increases, so glycated hemoglobin is lower than in non-pregnancy. Therefore, the target of glycated hemoglobin during pregnancy should be less than 6% to 6.5% in the first trimester and less than 6.0% in the second trimester, but less than 7% if the risk of hypoglycemia is high.

2. Medications

1) Insulin

(1) Insulin rarely crosses the placenta, so if medication is needed, insulin is recommended as the first treatment.

(2) Insulin therapy begins when exercise and diet cannot achieve glycemic control goals.

(3) The available baseline insulins are human insulin, NPH insulin, and insulin detemir among insulin analogues. Insulin glargine is still lacking in sufficient clinical research for use during pregnancy.

(4) The available fast-acting insulins are regular insulin, which is human insulin, and insulin lispro and insulin aspart.

(5) Usually, multiple injection or sustained subcutaneous injection therapy is used.

2) Oral hypoglycemic agents

(1) Metformin and glyburide have been shown to be effective and short-term safe, but some drugs have passed through the placenta and long-term safety has not yet been demonstrated.

(2) You may consider using metformin or glyburide if you are unable to use insulin or if your patient refuses to take insulin.

3. Determination of continued drug treatment after delivery

Insulin resistance, which has risen in the mid to late stages of pregnancy, is normalized after delivery, so blood glucose is normalized in most gestational diabetic mothers after delivery. However, gestational diabetes may be a type 1 or type 2 diabetes that has not been diagnosed before. Therefore, 75g oral glucose tolerance test should be performed at 4 to 12 weeks after delivery and the blood glucose level at the time of non-pregnancy may be used to maintain diabetes or diabetes. Check for the previous steps. Even with normal glucose tolerance, regular screening is recommended every 1 to 3 years, depending on whether you are at risk for developing diabetes, and pre-pregnancy counseling is required before planning your next pregnancy.


  • The weight gain of pregnant women should be enough to grow the fetus, and the change in weight gain as well as the total weight gain is important.
  • Meal therapy is the most important and basic way of managing diabetes.
  • Exercise is important for a healthy pregnancy with blood sugar control effects, so it’s best to do it every day.

1. Weight gain during pregnancy

1) It is desirable to increase the weight of pregnant women by about 0.5kg (0.3 ~ 0.7kg) a week during the second half of pregnancy. Pregnant women are usually expected to gain weight from 10 to 11kg, but if you are overweight you will increase your blood sugar, so you need to maintain a weight gain of about 300g a week to control your blood sugar.

2) Over 20% more weight than the standard weight is said to be overweight. Pregnant women who are overweight have a high incidence of gestational hypertension and preeclampsia.

3) Excessive weight gain or weight loss may increase your risk of premature birth and may not provide enough nutrients for fetal growth.

2. Diet Therapy

1) The goal of diet therapy is to control postprandial blood sugar, normal development of the fetus, prevention and alleviation of hypoglycemia, prevention of obstetric complications, proper weight gain and normalization of lipid metabolism.

2) Basically, three meals a day and two snacks or three meals and three snacks planned regularly, evenly divided and eat a small amount of snacks often helps to eat.

3) Snacks before bedtime is important for the prevention of ketosis caused by long-term fasting overnight. If a pregnant woman with diabetes does not eat for more than five hours, ketones are produced and should be prevented with complex carbohydrate and protein snacks. Although there is disagreement about the minimum caloric requirement in pregnant women with gestational diabetes, we do not recommend limiting daily calories below 1,700 to 1,800 kcal to prevent ketosis.

4) Carbohydrate is an important nutrient that affects post-prandial blood sugar. Carbohydrate-restricted meals are recommended to control postprandial blood sugar and are limited to 40-50% of total calories. In particular, sugar-based meals for breakfast are higher in blood sugar than other foods, so generally limit breakfast to 30-45g or less. Because the distribution of sugar affects blood sugar management, it is advisable to divide it evenly into three meals and two to four snacks. Evening snacks are necessary to prevent night-time ketosis.

5) Protein-rich foods can be used as a meal or snack as a food that can feel full without affecting blood sugar.

6) More fat is recommended than non-pregnant women and can consume up to 30-40% of total calories, but make sure saturated fats do not exceed 30% of total fat intake.

7) Creating a diet log will help you understand how your blood sugar changes with your meals.

8) In the case of insulin injections, skipping meals and snacks increases the risk of developing hypoglycemia.

3. Exercise Therapy

1) Effect of Exercise Therapy

(1) Exercise therapy is important for blood sugar control, but it also helps reduce stress and diversion. It can also help your appetite weight gain with appetite control.

(2) Regular exercise increases the action and effect of insulin in the body to keep blood sugar normal. It is especially effective in lowering postprandial blood sugar, which helps prevent excessive fetal growth.

2) Exercise recommended

(1) Walking 15 to 20 minutes fast twice a day after meals helps control blood sugar.

(2) It is safe to continue swimming even if you are pregnant or have been doing it before.

(3) It is recommended that exercise therapy based on upper body exercise during pregnancy does not cause uterine contractions.

3) Precautions during exercise

(1) Excessive exercise can be rather harmful, so exercise before pregnancy should be adjusted during exercise.

(2) Exercising such as tennis, volleyball, basketball, skiing, biking, or any other sports that are at risk of falls or cause a significant impact during exercise must be stopped until delivery.

(3) In general, your heart rate should not exceed 140 beats per minute, and one workout should not exceed 20 minutes.

(4) If you have dizziness or shortness of breath during exercise, or you may have symptoms of bleeding or bleeding, you should stop exercising immediately.

(5) It is better to refrain from exercise when there are hot and humid weather and heat in the body.

(6) It is very important to drink water before, during and after exercise to prevent dehydration.

(7) Insulin therapy may increase the risk of hypoglycemia during or after exercise, so be sure to bring candy or sugar when exercising to prepare for low blood sugar. If you exercise immediately after a meal, take a snack after exercise, and if you exercise more than two hours after eating, eat snacks before exercise.

(8) Exercise should be avoided during pregnancy if there is gestational hypertension, premature amniotic rupture, preterm labor, cervical disability, uterine bleeding, delayed intrauterine growth, and premature birth.

Frequently Asked Questions

  • If you are at high risk for gestational diabetes, screening may be done again after 32 weeks of pregnancy.
  • If your fasting blood sugar is very high, you will not be tested for glucose load.
  • If you are diabetic, we recommend breastfeeding.
  • Gestational diabetes does not increase the incidence of congenital malformations.

1. Do I need additional tests if my screening test is normal for 24 to 28 weeks?

If you are at high risk for gestational diabetes, you may be screened again after 32 weeks of gestation.

In high-risk groups with risk factors for developing gestational diabetes, screening may be performed again if normal on screening tests for 24 to 28 weeks of pregnancy. In particular, if only one level is high in the two-stage test, it is recommended to repeat the test after 32 weeks.

2. Do I have a glucose tolerance test if my fasting blood sugar is very high before giving glucose?

If the fasting blood sugar is very high before the administration of glucose, the glucose test is not done.

You can stop the test because very high fasting blood glucose by itself is sufficient for diagnosis and further glucose administration can be dangerous.

3. Can I breastfeed after giving birth?

If you are diabetic, we recommend breastfeeding.

1) Breastfeeding does not pass diabetes to the child, and breastfeeding is also desirable for the health of newborns and mothers.

2) Breastfeeding is the easiest way to return to your pre-pregnancy weight after delivery. Breastfeeding can consume calories and lower blood sugar, so consult with your doctor about preventing and treating hypoglycemia. In addition, if you are breastfeeding, it is recommended to keep calories during the second trimester or add 100 to 200 calories.

4. Will there be an increased incidence of birth defects if I have gestational diabetes?

Gestational diabetes does not increase the incidence of congenital malformations.

Gestational diabetes does not increase the incidence of congenital malformations by itself, unlike diabetes before pregnancy, which occurs mainly in the second and second weeks of pregnancy. However, other problems that can occur in other diabetic mothers can occur in common.

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