Gestational Diabetes


You may have heard of gestational diabetes, but what is this condition? During pregnancy, your metabolism changes to nourish the growing baby, and it processes sugar differently. The normal blood sugar levels are a little higher than when you are not pregnant because your body becomes more efficient at turning carbohydrates into energy. Sometimes these levels can become high enough to cause a woman to develop a diabetic condition during pregnancy even though she is not normally diabetic. This condition is called gestational diabetes.

The Hidden Diabetic

Many people are unaware they have diabetes until their symptoms become severe enough to send them to the doctor. A small number of women will first discover they have diabetes during routine prenatal care because this is the first time in their lives they have been tested for the condition. They had diabetes all the time, but they just didn't know it.

A woman with diabetes will usually have a family history of diabetes and may show signs and symptoms:

  • Extreme thirst
  • Excessive urination, both in frequency and quantity
  • Sugar in the urine
  • Ketones in the urine
  • Unexplained weight loss or weight gain

Pregnancy Induced Diabetes

Some non-pregnant women have "borderline diabetes" - or very mild diabetes. Their blood sugar levels are in the higher range of normal when they are not pregnant, although they do not reach diabetic levels. The metabolic changes of pregnancy raise their blood sugar levels high enough to tip them into overt diabetes. They have diabetes only when they are pregnant, and they return to normal levels after the baby is born. These women are commonly said to have gestational diabetes; although, it is more accurate to call their condition "pregnancy induced diabetes."

Diabetes can be a dangerous condition in pregnancy. The maternal risks are:

  • An increased risk of hypertension
  • A higher rate of pre-eclampsia
  • A higher risk of cesarean section
  • A risk that severe diabetes may develop

The fetal risks are:

  • Hydramnios, which is an excessive amount of amniotic fluid, also know as polyhydramnios.
  • The baby grows unusually large with excess fat deposits for its gestational age. This can lead to a difficult delivery.
  • Hypoglycemia, meaning a condition of low blood sugar after birth.
  • A slightly higher rate of stillbirth for unknown reasons.

The pregnant woman with diabetes will have to work closely with her doctor to find the correct diet or medications to control her blood sugar levels. With careful medical care, most diabetic women today can have safe pregnancies, normal births, and healthy babies.

Gestational Diabetes by Blood Test

Blood tests will generally identify a person with diabetes or gestational diabetes. A woman suspected of having diabetes will be offered a Glucose Tolerance Test or a Glucose Challenge Test (a GTT or GCT). For these tests, a sample of blood is taken, and then the patient is asked to drink a glass of high-glucose syrup. A blood sample is taken again at intervals over the next few hours, and the results are compared with the expected normal levels. The woman with gestational diabetes will spike abnormally high blood sugar levels, which stay high for at least two hours. The woman fails the test if at least two of the blood samples show her blood glucose is out of normal range.

Confusing Diagnosis

The GTT or GCT is controversial. It does a good job of detecting women who have diabetes, or who have pregnancy induced diabetes. The problem is it may incorrectly identify some women as diabetics even though they do not have the condition. This high rate of "false positives" causes unnecessary treatment and needless worry. Nearly half the women who fail the test will pass it again if they retake it another day. The blood test called A1c may be a better test than a GTT or GCT. This is beacause it gives information about your glucose levels over the last several months. It is more apt to give more information about the severity of the condition and may be less likely to produce a "false positive" result. Women who are at risk for gestational diabetes may want to consider asking their doctors for this test rather than a GTT or GCT screen.

Need For More Research

The best test to use to detect minor degrees of glucose intolerance is still uncertain. The best treatment for women with minor degrees of glucose intolerance, or who have moderately elevated glucose levels, is also uncertain. Currently, most practitioners agree that they should follow a healthy diet, Eating for Gestational Diabetes, which contains only moderate levels of complex carbohydrates, few simple carbohydrates, and avoids simple sugars and other sources of empty calories.

Gestational Diabetes