Friday, October 12, 2007

Diabetes Insulin Resistance of Pregnancy

One of the dominant metabolic effects of normal pregnancy is an increase in insulin resistance, probably induced by placental hormones including progesterone and placental lactogen. This leads to higher postprandial glucose concentrations that are considered to improve fetal growth; it is termed 'facilitated anabolism'. Fasting glucose concentrations decrease as a result of placental glucose transfer and in the later stages of pregnancy, there is also enhanced maternal lipolysis. This is considered to spare glucose for the fetus and is termed 'accelerated starvation'.

In genetically predisposed women, the normal insulin resistance of pregnancy may lead to the diagnosis of DM for the first time, termed 'gestational diabetes'. This may disappear within hours of giving birth depending on individual factors such as islet b-cell function and predisposing factors such as obesity. Women with pre-existing DM require higher doses of insulin during pregnancy and patients who are usually controlled using oral hypoglycemic agents are transferred to insulin at this time.

The effects of pregnancy-induced insulin resistance in women with DM lead to poorer control of blood glucose and also an increased likelihood of ketoacidosis. The hyperglycemia in early pregnancy has considerable effects on the development of the fetal pancreas. Maternal ketoacidosis leads to fetal loss.