oa Gestational diabetes mellitus screening and obstetrical complications: a review

Gestational diabetes mellitus (GDM) is a common medical complication that can have a profound impact on the mother and infant. It is defined as Carbohydrate intolerance of variable severity with onset or first recognition during the present pregnancy. The definition applies irrespective of whether or not insulin is used for treatment or the condition persists after pregnancy. It does not exclude the possibility that unrecognized glucose intolerance may have antedated the pregnancy.

The fasting plasma glucose levels are lower in normal pregnancy than in the nonpregnant state, and this decline occurs before any rise in fasting plasma insulin levels can be detected. The fasting levels of glucose fall despite a rise in hepatic glucose production, which serves to provide the needs of the developing fetus. The rise in plasma glucose following an oral glucose load or a normal meal is exaggerated. This occurs despite an increase in insulin secretion in response to both oral and intravenous glucose and to normal meals. This indicates that insulin sensitivity declines as pregnancy progresses. The postprandial glucose and insulin levels are increased further in the pregnant woman who is obese. Although glucose tolerance deteriorates in human pregnancy, about 97 to 98% of all pregnant women retain a normal glucose tolerance and only 2 to 3% develop gestational diabetes. However, the prevalence of GDM depends upon the genetic characteristics and environment of the population under study.