Gestational diabetes is a complication of pregnancy caused due to elevation of blood glucose levels. In women with gestational diabetes high blood glucose levels are first diagnosed during pregnancy. It affects about 4% of all pregnancies and in most women the blood glucose level returns to normal after the baby is born.
Glucose is the type of simple sugar that is formed by digestion and metabolism of the food you eat. The cells of the body use glucose as a source of energy (it is the main source of fuel for our bodies). The cells in the body need insulin for proper utilisation of glucose present in the blood. The hormone insulin is produced by the pancreas; a gland in the human body situated behind the stomach.
The pancreas secret the right amount of insulin in response to the rise in blood glucose levels after you eat something. In presence of the right amount of insulin the glucose from the blood moves into the cells where it is utilised for energy. However in diabetes, the pancreas either fail to secrete insulin or secrete less than required insulin, or the cells do not utilise the blood glucose even in presence of insulin (due to insulin resistance). This causes increase in blood glucose levels and if the blood glucose level becomes very high, glucose is excreted in urine.
In women with gestational diabetes such as type 1 and 2 diabetes the glucose is not utilised well by the cells of the body. The hormonal changes in pregnancy and the increased demand of insulin rae supposed to result in gestational diabetes. Women with gestational diabetes, secrete the right amount of insulin, however, the effect of insulin is partially blocked by the hormones produced by the placenta (such as progesterone, prolactin, estrogen, cortisol and human placental lactogen. These hormones help in proper progress of pregnancy).
Insulin resistance usually starts around 20 to 28 weeks of pregnancy when the placenta secretes more of these hormones. Initially most women secrete additional insulin to overcome insulin resistance but if all the insulin that pancreas can make is not enough to overcome the effect of these hormones, then gestational diabetes results.