Long-term complications of diabetes develop gradually. The longer you have diabetes — and the less controlled your blood sugar — the higher the risk of complications. Eventually, diabetes complications may be disabling or even life-threatening. Possible complications include:

  • Cardiovascular disease. Diabetes dramatically increases the risk of various cardiovascular problems, including coronary artery disease with chest pain (angina), heart attack, stroke and narrowing of arteries (atherosclerosis). If you have diabetes, you are more likely to have heart disease or stroke.
  • Nerve damage (neuropathy). Excess sugar can injure the walls of the tiny blood vessels (capillaries) that nourish your nerves, especially in the legs. This can cause tingling, numbness, burning or pain that usually begins at the tips of the toes or fingers and gradually spreads upward. Left untreated, you could lose all sense of feeling in the affected limbs. Damage to the nerves related to digestion can cause problems with nausea, vomiting, diarrhea or constipation. For men, it may lead to erectile dysfunction.
  • Kidney damage (nephropathy). The kidneys contain millions of tiny blood vessel clusters (glomeruli) that filter waste from your blood. Diabetes can damage this delicate filtering system. Severe damage can lead to kidney failure or irreversible end-stage kidney disease, which may require dialysis or a kidney transplant. The rates of serious kidney disease have dropped significantly in recent years, likely due to improvements in diabetes management.
  • Eye damage (retinopathy). Diabetes can damage the blood vessels of the retina (diabetic retinopathy), potentially leading to blindness. Diabetes also increases the risk of other serious vision conditions, such as cataracts and glaucoma.
  • Foot damage. Nerve damage in the feet or poor blood flow to the feet increases the risk of various foot complications. Left untreated, cuts and blisters can become serious infections. Severe damage might require toe, foot or even leg amputation.
  • Skin and mouth conditions. Diabetes may leave you more susceptible to skin problems, including bacterial and fungal infections. Gum infections also may be a concern, especially if you have a history of poor dental hygiene.
  • Osteoporosis. Diabetes may lead to lower than normal bone mineral density, increasing your risk of osteoporosis.
  • Alzheimer's disease. Type 2 diabetes may increase the risk of Alzheimer's disease. The poorer your blood sugar control, the greater the risk appears to be. One theory is that cardiovascular problems caused by diabetes could contribute to dementia by blocking blood flow to the brain or causing strokes. Other possibilities are that too much insulin in the blood leads to brain-damaging inflammation, or lack of insulin in the brain deprives brain cells of glucose.
  • Cancer. People with diabetes have a higher risk of some cancers. But the reasons aren't clear. It may be that the factors that increase the risk of type 2 diabetes also increase the risk of cancer, or it may be a factor of the disease or its treatment. This is an active area of research, but in the meantime, no changes in treatment are recommended.

Complications of gestational diabetes

Most women who have gestational diabetes deliver healthy babies. However, untreated or uncontrolled blood sugar levels can cause problems for you and your baby.

Complications in your baby can occur as a result of gestational diabetes:

  • Excess growth. Extra glucose can cross the placenta, which triggers your baby's pancreas to make extra insulin. This can cause your baby to grow too large (macrosomia). Very large babies are more likely to require a C-section birth.
  • Low blood sugar. Sometimes babies of mothers with gestational diabetes develop low blood sugar (hypoglycemia) shortly after birth because their own insulin production is high. Prompt feedings and sometimes an intravenous glucose solution can return the baby's blood sugar level to normal.
  • Respiratory distress syndrome. If your baby is delivered early, respiratory distress syndrome — a condition that makes breathing difficult — is possible. Babies who have respiratory distress syndrome may need help breathing until their lungs become stronger.
  • Jaundice. This yellowish discoloration of the skin and the whites of the eyes may occur if a baby's liver isn't mature enough to break down a substance called bilirubin, which normally forms when the body recycles old or damaged red blood cells. Although jaundice usually isn't a cause for concern, careful monitoring is important.
  • Type 2 diabetes later in life. Babies of mothers who have gestational diabetes have a higher risk of developing obesity and type 2 diabetes later in life.
  • Death. Untreated gestational diabetes can result in a baby's death either before or shortly after birth.

Complications in you can also occur as a result of gestational diabetes:

  • Preeclampsia.This condition is characterized by high blood pressure, excess protein in the urine, and swelling in the legs and feet. Preeclampsia can lead to serious or even life-threatening complications for both mother and baby.
  • Subsequent gestational diabetes. Once you've had gestational diabetes in one pregnancy, you're more likely to have it again with the next pregnancy. You're also more likely to develop diabetes — typically type 2 diabetes — as you get older.

Complications of prediabetes

Prediabetes may develop into type 2 diabetes.

Jan. 31, 2013