Gestational Diabetes - Pregnancy And Diabetes: Diabetes

Content provided by the Faculty of the Harvard Medical School

Gestational diabetes

Gestational diabetes — diabetes that develops during pregnancy — occurs in 3%–5% of pregnancies, usually in the last trimester. This form of diabetes doesn't increase the risk for birth defects. The real worry is having an exceptionally large fetus, which makes having a cesarean section or preterm delivery more likely. Babies delivered to women with gestational diabetes also have a higher rate of hypoglycemia right after birth.

Gestational diabetes typically disappears after delivery, but up to half of these women later develop type 2 diabetes, usually 5–10 years after the pregnancy. Women who've had gestational diabetes should have an oral glucose tolerance test within three months of delivery and continue to have their fasting blood sugar levels checked at least annually.

This form of diabetes seems to resemble type 2 diabetes, and women who are over age 30, overweight, and have a family history of diabetes are more prone to it. It's also more common in women who previously delivered a baby weighing more than 9 pounds or a stillborn infant.

Testing for gestational diabetes

A blood screening test — a 50-gram oral glucose tolerance test usually given between the 24th and 28th weeks of pregnancy (or earlier if gestational diabetes occurred during a former pregnancy) — can uncover this problem. Gestational diabetes is suspected if your plasma glucose level is 140 mg/dL or higher one hour after ingesting 50 grams of glucose. This finding is then confirmed by a second test, which requires drinking 100 grams of glucose.

Managing gestational diabetes

Following a diet and exercise plan may be enough to keep your blood sugar levels tightly controlled during pregnancy. However, insulin resistance tends to increase in the latter part of pregnancy. If your blood sugar level before a meal is more than 105 mg/dL, your doctor will probably recommend insulin. Other medications for blood sugar control are not recommended for pregnant women.

Last updated:	January 23, 2007