Gestational diabetes mellitus, or GDM, is diabetes that first appears in pregnancy and resolves at birth. An estimated 200,000 American women, approximately 5% of total pregnancies, are diagnosed with GDM annually. Women who develop gestational diabetes have problems metabolizing blood glucose. Their pancreas produces plenty of insulin (the hormone responsible for "unlocking" cells so that glucose can enter them and provide energy), but a condition known as insulin resistance prevents them from using it effectively. When insulin doesn't work properly, blood glucose (or blood sugar) builds up in the bloodstream, and gestational diabetes is the result.
Gestational diabetes requires treatment with dietary changes and exercise and/or insulin injections to keep maternal blood glucose levels as close to normal as possible and to prevent complications in both mother and baby. Women with GDM are also encouraged to self-test their blood glucose levels often.
A fetus of a woman with GDM may become large for date as it stores the excess glucose it is receiving from mom as fat, a condition known as macrosomia. A large infant may have a more difficult time descending down the birth canal. Other potential risks for baby include hypoglycemia (low blood sugar) and jaundice. A neonatolgist, a physician that specializes in high risk infant care, is often present at the births of GDM babies to handle any potential complications.
The hormones produced by the placenta in pregnancy-including estrogen, cortisol, and human placental lactogen (HPL)-are what trigger the insulin resistance in women predisposed to the condition. As pregnancy progresses and the placenta grows larger, hormone production also increases and so does the level of insulin resistance. This process usually starts between 20 and 24 weeks of pregnancy. At birth, when the placenta is delivered, the hormone production stops and so does the GDM.
Risk factors for developing gestational diabetes include: