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What Is Gestational Diabetes?

Gestational diabetes — diabetes that develops during pregnancy — is a relatively common complication, striking about 4% of all pregnant women.

You may have a greater risk of developing gestational diabetes if you:

• Are obese when you become pregnant.
• Have high blood pressure or other medical complications.
• Have given birth to a large (greater than 9 pounds) baby before.
• Have given birth to a baby that was stillborn or suffering from certain birth defects.
• Have had gestational diabetes before.
• Have a family history of diabetes.
• Come from certain ethnic backgrounds, including African, Hispanic, Asian, Native American or Pacific Islander.
• Are older than 30 years.

But half of women who develop gestational diabetes have no risk factors.

If untreated, gestational diabetes can cause serious complications for your newborn. For example, babies of untreated mothers may grow too large (called macrosomia), increasing the risk of problems during birth, such as injuries to their shoulders and arms. Having a very large baby may also increase your risk for requiring a cesarean section or other assistance during delivery (such as a forceps or vacuum delivery). Your baby may also experience a sudden, large drop in blood sugar after birth, requiring treatment with a sugar solution given through a needle in the vein. Your newborn baby may also have a higher risk of developing jaundice and breathing problems.

The risk of birth defects in infants whose mothers have gestational diabetes is very low because most gestational diabetes develops after the 20th week of pregnancy, when the fetus has already fully developed. The risk increases only if you had undiagnosed diabetes before pregnancy or if you run high, out-of-control blood sugar levels during the first six to eight weeks of pregnancy

If you have gestational diabetes, your baby does not have an increased risk of developing type I diabetes during childhood. However, your child is more likely to develop type 2 diabetes later in life as well as be overweight throughout life.

Most women's blood sugar levels return to normal after delivery. Once you've had gestational diabetes, however, you are more likely to develop gestational diabetes again during subsequent pregnancies. You also have an increased risk of developing diabetes later in your lifetime; you stand a 50% chance of developing diabetes within 10-20 years of delivery.

What Causes It?
Gestational diabetes is the result of some changes that occur in all women during pregnancy. Increased levels of certain hormones (including cortisol, estrogen, and human placental lactogen) interfere with the ability of insulin to manage blood sugar. This condition is called "insulin resistance." Usually your pancreas (the organ that produces insulin) is able to compensate for this insulin resistance by increasing insulin production (to about three times the normal amount). If your pancreas cannot sufficiently increase insulin production to overcome the effect of the increased hormones, your blood sugar levels will rise — that means you have gestational diabetes.

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