Symptoms of Gestational Diabetes: Learn About the Symptoms, Diagnosis, and Effects on the Fetus of Gestational Diabetes

Page content

Part 1 of the series on gestational diabetes discussed the cause and listed risk factors for developing this disease. Symptoms, diagnosis, and effects on the fetus are explained here in Part 2 of the series.

Pregnant women may be screened for gestational diabetes, a serious but often symptomless disease affecting pregnant women and their fetuses.


Symptoms of gestational diabetes, if present at all, may include increased thirst and increased need for urination. However, the latter may be overlooked as a normal symptom of pregnancy. Other potential symptoms include fatigue, nausea, blurred vision, and infections. In most cases, however, no symptoms are present at all.

Screening and Diagnosis

Because gestational diabetes is often asymptomatic, many practitioners routinely screen obstetric patients for it, usually around 24-28 weeks. One common screening, called a glucose challenge test, involves consumption of a high-glucose liquid followed after a set period of time by a blood test for glucose. Practitioners may opt instead to screen based on the fasting or postprandial (after-meal) glucose level. They may also routinely check their patients’ urine for glucose.

If a pregnant patient has a positive screening, she may be referred for an oral glucose tolerance test (OGTT). An OGTT requires overnight fasting, followed by consumption of a concentrated glucose solution. Blood is drawn for glucose testing one, two, and three hours later. High results on these tests result in a positive diagnosis of GD.

Effects on the Fetus

Untreated gestational diabetes carries serious risks for the fetus. Glucose, a source of energy, is associated with fetal growth, so a constant high level of glucose can result in macrosomia (large body size). Shoulder dystocia, in which the shoulders become stuck in the birth canal during vaginal delivery, is a possibility with macrosomia, and can lead to permanent nerve damage or even death in the infant. Macrosomia also increases the risk of instrument use during birth and of cesarian section.

Glucose crosses the placenta, but insulin does not. Thus when blood glucose is uncontrollably high, the fetus manufactures high levels of insulin. At birth, when the high glucose supply from the placenta is cut off, the infant’s blood glucose can plummet dangerously, a condition known as hypoglycemia.

GD is also associated with jaundice, respiratory distress syndrome, and other conditions that may affect the neonate. GD may raise the risk of preeclampsia, a gravely serious condition that threatens both the mother and the fetus. The only cure for preeclampsia is delivery, which may mean premature birth for the baby.

Continue to Part 3 of the series on gestational diabetes to learn how it is treated, including information on diet, exercise, and medication, and to find out how it can affect the long-term health of both mother and baby.