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About Gestational Diabetes

Pregnant women who have not previously been diagnosed with diabetes may develop high blood glucose levels during their second or third trimester of pregnancy. When high glucose levels are discovered during pregnancy the woman is diagnosed as having gestational diabetes. This means that the mother’s body is not able to make and use all of the insulin it needs for pregnancy.

Testing for this type of diabetes is common as part of good pregnancy care. High glucose levels increases the risk for complications to both mother and baby and needs to be medically managed immediately upon diagnosis.

Statistics of Gestational Diabetes

The prevalence of gestational diabetes is found to be as high as 9.2% with pregnant women. In most situations gestational diabetes will go away after birth of the baby, however in five to 10% of women the blood glucose levels do not return to normal and the diagnosis changes to type 2 diabetes

Cause of Gestational Diabetes

The specific reason why gestational diabetes occurs is not known; however, research has given us a better understanding of why it occurs during pregnancy:

  • the woman’s placenta supports the growth and development of the baby
  • hormones from the placenta help the baby to develop
  • these pregnancy hormones block the action of the mother’s insulin in her body
  • when the mother’s insulin is restricted a problem called insulin resistance develops
  • insulin resistance makes it hard for the mother’s body to use the insulin effectively
  • the mother may need up to three times as much insulin during pregnancy to keep glucose levels under control

Treatment of Gestational Diabetes

With this type of diabetes the mother may need to:

  • modify their eating patterns
  • increase physical activity
  • take medications (oral and/or insulin)
  • check blood glucose levels as directed

Risk Factors and Complications

Gestational diabetes which develops in later pregnancy, typically around 24 weeks, does not cause the kinds of birth defects that can occur with mothers who had type 2 diabetes before pregnancy. High glucose levels not properly controlled however, can impact the baby’s health at birth and later in life.

During pregnancy the mother’s production of insulin does not cross over into the placenta but the excess glucose does. The fetus receives extra blood glucose which in turn causes the baby’s pancreas to make extra insulin to remove the extra blood glucose from its body.

Some specific complications that can occur include:

  • Macrosomia – With the baby getting more energy through elevated blood glucose levels than it needs to grow and develop, the extra energy is stored as fat. The baby can be born diagnosed with macrosomia, also known as a “fat” baby; these children face health problems at birth and later on as they grow.
  • Breathing problems – babies who have very low blood glucose levels at birth (due to production of extra insulin to combat the increased blood glucose levels)


Risk for obesity – babies who produce excess insulin often become children at risk for obesity and then adults at risk for type 2 diabetes