Important Facts on Gestational Diabetes

Gestational diabetes affects 135,000 pregnant women per year in the United States, which works out to an annual incidence of 3-5% of all pregnant women. The incidence in Australia is expressed differently, where it affects 9% of all new cases of diabetes per year.  Women who have gestational diabetes have been found to have a 20% to 50% chance of having Type II diabetes later in life.

Gestational diabetes occurs because the hormones in pregnancy interfere with the body’s ability to use insulin and the blood sugar rises.  The blood sugar crosses the placenta and provides a high sugar environment to the fetus.  The fetus grows larger that average and its pancreas kicks in and makes too much insulin while it is in the mother’s womb. 

There generally are no symptoms of gestational diabetes although excessive weight gain is often seen in the pregnancy.  The mother can also have increased frequency of urination.  With so few symptoms, all pregnant mothers need to be screened for gestational diabetes.  This happens around 24 weeks gestation and takes about an hour to do.  The mother is given a fifty gram load of a sugary liquid to drink.  The blood sugar is checked an hour later and if abnormal, a diagnosis of gestational diabetes is made.  Sometimes another three hour test is required to confirm the diagnosis.

After the diagnosis of gestational diabetes is made, the woman is treated much like a diabetic.  She must see a diabetic nutritionist and must measure her blood sugar several times a day and follow a low sugar diet.  If the blood sugars can’t be controlled with diet alone, then insulin in several doses during the day must be given.  This should slow down the fetal weight gain.

Because of an increased risk of fetal distress with gestational diabetes in later pregnancy, the mother must begin to have evaluations of the fetal condition with a fetal nonstress test at around thirty six weeks gestation.  These tests are done at a minimum of once per week until the baby is born.  If there is evidence of fetal distress at rest, then sometimes a stress test is done that evaluates how the baby will do under conditions of labor.  If the baby passes this test, the doctor can often induce labor without difficulty.  If the fetus fails the stress test, the baby is almost always delivered by Cesarean section.

The baby in pregnancies complicated by gestational diabetes is often delivered at or before term so that the baby does not get too big.  After the baby is born, the mother is checked to see whether or not she has diabetes Type II or just gestational diabetes.  The infant is also evaluated.  This is because infants with gestational diabetes can have breathing problems after birth and because the infant’s overactive pancreas can lower the blood sugar in the baby right after birth.  The infant may need intravenous fluids with sugar in them or they may need to be feed relatively quickly.  Either way, the infant must have its blood sugar checked frequently in the first few days of life to make sure it never gets low.