What tests should be done to evaluate the patient’s glucose tolerance? How is the diagnosis of gestational diabetes mellitus (GDM) established? What would be the best treatment and follow-up strategy?

Case Study: A 34-Year-Old Woman in Her Second Pregnancy at 24 Weeks Gestation

Presentation
A 34-year-old Hispanic-American woman who is in her second pregnancy and has had one live birth and no abortions is seen for prenatal care at 24 weeks gestation. Her weight is 220 lb, and her blood pressure is 130/80 mmHg. Uterine size is appropriate for gestational age. The patient’s past obstetric history includes the spontaneous vaginal delivery of a 9 lb, 8 oz. male infant at 40 weeks gestation, 8 years ago in Mexico. The patient reports that the child is doing well. Her family history reveals that her mother has type 2 diabetes mellitus. A urine dipstick shows 3+ glycosuria and negative ketones.

Questions
1. What tests should be done to evaluate the patient’s glucose tolerance?
2. How is the diagnosis of gestational diabetes mellitus (GDM) established?
3. What would be the best treatment and follow-up strategy?