Gestational Diabetes
Gestational diabetes mellitus (GDM) is defined as a carbohydrate
intolerance of variable severity with onset or first recognition during
pregnancy. Although medical science is unsure of the cause of this disorder
they believe it results from one of three things.
1. An unidentified preexisting disease.
2. The unmasking of a compensated metabolic abnormality by the added stress
of pregnancy.
3. A direct consequence of the altered maternal metabolism stemming from
changing hormonal levels.
What is known is that the way the placenta works may in relation to these
three things may lead to gestational diabetes. As the baby grows the
placenta is its main avenue of life support. The hormones that the placenta
makes to help the baby grow have a negative effect on the mother's insulin.
These hormones diminish her insulin's ability to move glucose out of the
blood stream and into the cells. This is known as insulin resistance and the
mother may need to produce more than three times her normal insulin
requirement.
As the pregnant woman's body becomes unable to produce enough insulin to
deal with rising blood glucose levels she will start to become
hyperglycemic. In a pregnancy this is gestational diabetes.
When gestational diabetes is diagnosed, the goal of treatment is to decrease
the likelihood of fetal macrosomia, shoulder dystocia, birth trauma, and
cesarean birth.
Once the baby is born gestational diabetes tends to go away. Although
gestational diabetes incidence rates vary, many women who suffer it will
progress to overt type 2 diabetes with time. This is because once a woman
has suffered from this condition she is two-thirds more likely to suffer it
in future pregnancies. For reasons not known there is a direct link between
women who have gestational diabetes who later get type 2 diabetes.
Women who are not diabetic are still at risk for gestational diabetes. If
tests reveal high blood sugar levels during a pregnancy then that woman is
at risk for this type of diabetes. About 135,000, or 4% of all pregnant
women, are affected by gestational diabetes in the United State every year.
All women who are pregnant, regardless of their risk, should be screened for
gestational diabetes toward the end of their second trimester (24 to 28
weeks) using the 1 hour, 50g oral glucose tolerance test.
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