Diabetes in pregnancy can cause many complications starting with major congenital anomalies and fetal growth restriction in the first trimester and chronic hyperinsulinism in the second to third trimester causing multiple disorders/diseases presenting after delivery; it can then continue to cause transgenerational effects (increased risk of type 2 diabetes mellitus [T2DM], obesity, and kidney disease) later on in life. Because of an improved understanding of the pathophysiology of diabetic pregnancies, these complications can be recognized and treated. Data indicate that perinatal morbidity and mortality rates in infants of diabetic mothers (IDM) have improved with dietary management and insulin therapy.
Definitions. Any form of diabetes mellitus (DM) may require insulin. It is important to note, as stated by the American Diabetes Association, that “insulin use does not classify the patient.” Types of diabetes during pregnancy are:
Pregestational diabetes mellitus (PGDM) is diabetes that is diagnosed before pregnancy; 15% of pregnancies are complicated by PGDM.
Type 1 diabetes (T1DM) occurs due to autoimmune B-cell destruction, which causes an insulin deficiency.
Type 2 diabetes (T2DM) is caused by a progressive loss of B-cell insulin secretion with a background of insulin resistance.
Preexisting pregestational diabetes is diabetes diagnosed in women by standard diagnostic criteria in the first trimester. The diabetes is usually type 2; rarely is it type 1 or monogenic diabetes.
Gestational diabetes (GDM) is diabetes diagnosed in the second or third trimester of pregnancy with no signs of preexisting T1DM or T2DM prior to the pregnancy. When present, GDM results in complications in 85% of pregnancies.
White classification. The White classification is a list of alphabetically assigned categories of diabetes and their severity in pregnancy. It is based on age of onset, duration of the disease, and presence or absence of vascular complications. The original White classification (1949) was most likely based on T1DM and was used to assess maternal and fetal risk. There have been multiple revisions, each adding more detail, with the latest 1980 revision including the addition of GDM as a separate class and hypertension risks. See Table 101–1.
American Diabetes Association classification (2014) presents 4 categories of diabetes. T1DM and T2DM are based on pathophysiology of the disease, and the other category is based on specific types of diabetes due to other causes. GDM is based on the time of diagnosis and the glucose tolerance results. See Table 101–2.
Globally, the incidence of diabetes is increasing. The International Diabetic Federation estimated that approximately 16% of babies born in 2015 were exposed to hyperglycemia, approximately 85% due to GDM, approximately 7.5% due to PGDM (type 1 or type 2), and 7.4% due to other types of diabetes.
Gestational diabetes. The incidence of GDM varies greatly depending on population characteristics, diagnostic criteria, genetic factors, and screening methods. Globally, the incidence varies from 1% to 28%. The ...