Gestational Diabetes Mellitus (GDM) is a condition characterized by an increase in blood sugar levels during pregnancy. While the causes of gestational diabetes can affect any pregnant woman, there are some factors that make certain women highly susceptible to the condition. Some of these triggering factors include:

• Obesity
• A family history of diabetes mellitus
• Previous delivery of a baby with birth weight more than 4 kilograms
• The presence of glucose in the urine (glycosuria)

The Common Causes Of Gestational Diabetes

GDM can be caused by the dysfunctioning of the beta cells (cells that secrete insulin) of the pancreas. Some of the other causes of gestational diabetes include:

• Autoimmune Causes

  A study conducted in women with gestational diabetes mellitus revealed the presence of self-destructing (autoimmune) antibodies. These are directed against the pancreatic islets and are called anti-islet antibodies. Due to the presence of these antibodies, the insulin secretion is inadequate and fails to match the increased insulin demand that is seen during pregnancy. This leads to gestational diabetes mellitus.

• Monogenic Causes

  The autosomes and mitochondrial DNA present in the body regulate insulin secretion. Some of the important genes involved in this process are glucokinase, hepatocyte nuclear factor 1α, and the insulin promoter factor 1. Detailed metabolic studies have revealed abnormalities in glucose-mediated insulin secretion due to mutations in these genes. Such abnormalities can lead to a decrease in insulin secretion and in turn lead to gestational diabetes mellitus.

• Insulin Resistance

  This is a major factor that triggers gestational diabetes mellitus, as the body’s sensitivity to insulin decline with the progress of the pregnancy.

  Studies have revealed increased circulating levels of leptin and the inflammatory markers TNF-α and C-reactive protein, and decreased levels of adiponectin in women with gestational diabetes mellitus. Increased content of fat in the liver and muscle has also been reported in women with a history of gestational diabetes. Women with GDM show variation in genetic coding for:

  • Glucokinase, which is important for the response produced by the beta cells in the presence of glucose
  • Calpain-10, which is commonly associated with non insulin-dependent diabetes mellitus, especially in Hispanic Americans and some other ethnic groups
  • The sulfonylurea receptor 1, which regulates insulin secretion in response to glucose
  • The β3 adrenoreceptor, which is said to be involved in fat regulation in the body

If GDM is left untreated, it can cause various complications both during and after the pregnancy. As the causes of gestational diabetes are varied, it is advisable for every pregnant woman to undergo screening for GDM.