Gestational Diabetes in Pregnancy (GDM)

Elie Hobeika MD, FACOG
Assistant Professor, Clinical Obstetrics & Gynecology, AUBMC
Medical Director, Department of Obstetrics & Gynecology, KMC

Diabetes complicates 2-3% of pregnancies. Most cases of diabetes complicating pregnancy are GDM that begins or is first recognized during pregnancy with an incidence of 1-14%.

The American College of Obstetricians and Gynecologists (ACOG) recommends universal screening for pregnant women using 50 grams oral glucose tolerance test between 24 and 28 weeks. If the number is above 140 mg/dl, a diagnostic test consisting of 100 grams of glucose, with a 3-hour oral glucose tolerance test is needed. Two abnormal values are needed to make the diagnosis of gestational diabetes mellitus (GDM).

Unlike women with pre-pregnancy diabetes, fetal anomalies are not increased in infants of mothers with GDM. Nonetheless, fetal death is a little higher than the general population.

Macrosomia (large baby) has been observed in as many as 50% of pregnancies complicated by GDM.

Women with GDM are more likely to develop hypertensive disorders and be delivered by cesarean section compared to women without GDM.

The mainstay of treatment of GDM is nutritional counseling and dietary intervention.

The recommended daily caloric intake is 30 kcal/kg based on pre-pregnant body weight for non-obese and 24 kcal/kg for obese patients.

The caloric composition includes 40– 50% from complex, high-fiber carbohydrates; 20% from protein; and 30–40% from primarily unsaturated fats.

Surveillance of blood glucose level is necessary. Fasting plasma glucose levels should be maintained below 95 mg/dl and below 120 mg/dl 2 hours after eating, in women with GDM.

When standard dietary management does not maintain these glucose levels, medications are needed in the form of pills (glyburide or metformin) or, if insufficient, shots (insulin) are then recommended.

For well-controlled GDM, antepartum testing is not needed and vaginal delivery can happen at term with cesarean section reserved for large babies above 4500 grams. For uncontrolled GDM or GDM requiring medications to control the blood sugar, antepartum testing is needed and early delivery might be helpful.

It is recommended that women with GDM receive a post-partum evaluation with a 75-g glucose tolerance test. This is based on the 30- 50% likelihood of such women developing diabetes within 20 years of delivery.

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