Gestational Diabetes Screening

Gestational diabetes is a type of diabetes that is found only in pregnancy. Because of hormones produced by the placenta, women have changes in the way their body uses sugar and insulin. One of the hormones that is felt to affect this the most reaches a maximal level between 24 and 28 weeks.

Risk factors for development of gestational diabetes:

Age >25

Obesity—women with a BMI of 30 or higher are more likely to develop gestational diabetes

Have a history of gestational diabetes with a prior pregnancy

Have a history of insulin resistance or “prediabetes”

Have a first degree relative such as a parent or sibling with type 2 diabetes

Had problems with a prior pregnancy such as a large baby (greater than 9 pounds) or an unexplained stillbirth

Race—though it is not known why, women who are Hispanic, black, American Indian, Asian, or Pacific Islander are more likely to develop gestational diabetes

Testing for Gestational Diabetes

Our office screens ALL patients between 24 and 28 weeks of pregnancy.

The day of your test, do not eat or drink anything after midnight. When you arrive to the office, typically around 8AM, you will be given a drink that contains a known amount of glucose (sugar). One hour after finishing this, your blood will be drawn and your glucose level measured. If this level is above a certain cutoff, your provider will call you to discuss the next step in testing with you.

If your blood sugar is above normal, the next test we perform is called a 3 hour glucose tolerance test. On the day of your test, do not eat or drink anything after midnight. On arrival to the office, your blood will be drawn and a fasting blood sugar checked. You will then be given a drink similar to the drink you had before—this contains a known amount of glucose. You will then have blood checks one, two, and three hours after you finish the drink. If this is abnormal, you are considered to have gestational diabetes.

Risks of gestational diabetes

Risks to the baby:

Large baby: some babies born to mothers with diabetes are above average in size. This can decrease the mother’s ability to deliver the baby safely vaginally.

Low blood sugar in the newborn infant (hypoglycemia): when a mother has diabetes and high levels of glucose, the baby responds by making more insulin to store the extra glucose. After birth, some babies have insulin levels that are too high. In the most severe instance, this can provoke seizures in the baby. Sometimes babies have to be watched carefully in the nursery to monitor for this.

Jaundice: a yellow discoloration of the skin and eyes that occurs when the baby has a difficult time breaking down a substance called bilirubin. This is a natural by-product formed from the breakdown of red blood cells. This is typically not severe, but can require treatment and careful monitoring.

Future development of diabetes

Increased risk of stillbirth or death shortly after birth

Risks to the mother:

Future development of diabetes (gestational diabetes with subsequent pregnancy or Type II diabetes): this can be diminished with a healthy diet, exercise, and weight loss. Women who lose weight and reach their ideal body weight after delivery are at a substantially reduced risk of developing diabetes.

Pre-eclampsia: this is high blood pressure associated with protein in the urine. This can lead to very serious complications including preterm birth, seizures, stroke, and fetal death.

Infections: women with diabetes are at a higher risk of developing infections, most commonly in pregnancy, urinary tract infections

What happens if I am diagnosed with gestational diabetes?

If your screening test and your 3 hour glucose tolerance test are abnormal, then you have gestational diabetes. There are two different kinds of gestational diabetes—diet controlled (sometimes classified as A1 gestational diabetes) and insulin-requiring diabetes (A2 gestational diabetes). Initially, you will be referred to classes to help teach you how to follow a diabetic diet. Most people can control their blood sugars with diet alone. Though rare, some people do require insulin for management of blood sugars to reduce the risk of maternal or fetal harm.