There are two types of diabetes that occur in pregnancy: With
both types of diabetes, there can be complications for the baby.
It is very important for a mother to maintain very close control
of her diabetes during pregnancy. The placenta supplies a
growing fetus with nutrients and water, as well as 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 the placenta grows, more of these hormones are
produced, and insulin resistance becomes greater. Normally, the
pancreas is able to make additional insulin to overcome insulin
resistance, but when the production of insulin is not enough to
overcome the effect of the placental hormones, gestational
diabetes results. Pregnancy also may change the insulin needs of
a woman with existing diabetes as a medical condition. Insulin-
dependent mothers may r