Gestational diabetes mellitus is a condition in which the
glucose level is elevated and other diabetic symptoms appear
during pregnancy in a woman who has not previously been
diagnosed with diabetes. All diabetic symptoms disappear
following delivery. Unlike type 1 diabetes, gestational diabetes
is not caused by a lack of insulin, but by other hormones
produced during pregnancy that can make insulin less effective,
a condition referred to as insulin resistance. Approximately 3
to 8 percent of all pregnant women in the United States are
diagnosed with gestational diabetes. Although the cause of GDM
is not known, there are some theories as to why the condition
occurs. The placenta supplies a growing fetus with nutrients and
water, and also produces a variety of hormones to maintain the
pregnancy. Some of these hormones (estrogen, cortisol, and human
placental lactogen) can have a blocking effect on insulin. This
is called contra-insulin effect, which usually begins about 20
to 24 weeks into the pregnancy. As th