Pregnancy and Gestational Diabetes
What is Gestational Diabetes?
What Causes Gestational Diabetes?
Almost all women have some degree of impaired glucose intolerance as a result of hormonal changes that occur during pregnancy. That means that their blood sugar may be higher than normal, but not high enough to have diabetes. During the later part of pregnancy (the third trimester), these hormonal changes place pregnant woman at risk for gestational diabetes.
During pregnancy, increased levels of certain hormones made in the placenta (the organ that connects the baby by the umbilical cord to the uterus) help shift nutrients from the mother to the developing fetus. Other hormones are produced by the placenta to help prevent the mother from developing low blood sugar. They work by resisting the actions of insulin.
Over the course of the pregnancy, these hormones lead to progressive impaired glucose intolerance (higher blood sugar levels). To try to decrease blood sugar levels, the body makes more insulin to get glucose into cells to be used for energy.
Usually the mother's pancreas is able to produce more insulin (about three times the normal amount) to overcome the effect of the pregnancy hormones on blood sugar levels. If, however, the pancreas cannot produce enough insulin to overcome the effect of the increased hormones during pregnancy, blood sugar levels will rise, resulting in gestational diabetes.
What Are the Complications of Gestational Diabetes?
Diabetes can affect the developing fetus throughout the pregnancy. In early pregnancy, a mother's diabetes can result in birth defects and an increased rate of miscarriage. Many of the birth defects that occur affect major organs such as the brain and heart.
During the second and third trimester, a mother's diabetes can lead to over-nutrition and excess growth of the baby. Having a large baby increases risks during labor and delivery. For example, large babies often require caesarean deliveries and if he or she is delivered vaginally, they are at increased risk for trauma to their shoulder.
In addition, when fetal over-nutrition occurs and hyperinsulinemia results, the baby's blood sugar can drop very low after birth, since it won't be receiving the high blood sugar from the mother.