Screening for Gestational Diabetes Mellitus in Pregnant Women

Early Pregnancy Screening

The American College of Obstetricians and Gynecologists recommends early screening with FBS or any glucose test at the first prenatal visit (12-14 weeks) for women with a history of GDM, and if negative, mandatory 75g OGTT screening at 24-28 weeks 1, 2
Women with a history of previous GDM have a 4.14 times higher risk of developing GDM in the current pregnancy 2
The American Diabetes Association recommends using FBS or random plasma glucose to detect overt diabetes at the first prenatal visit, with a threshold of FBS ≥126 mg/dL or random glucose ≥200 mg/dL with symptoms 3

The American College of Obstetricians and Gynecologists and the American Diabetes Association recommend universal screening for GDM at 24-28 weeks, using either a one-step approach with 75g OGTT or a two-step approach with 50g GCT followed by 100g OGTT 1, 4, 5
The one-step approach requires only one abnormal value (fasting ≥92 mg/dL, ogle 1-hour ≥180 mg/dL, or 2-hour ≥153 mg/dL) for diagnosis, while the two-step approach requires at least two abnormal values (fasting ≥95 mg/dL, 1-hour ≥180 mg/dL, 2-hour ≥155 mg/dL, or 3-hour ≥140 mg/dL) 4, 5, 6

The American College of Obstetricians and Gynecologists recommends that all women diagnosed with GDM undergo 75g OGTT at 4-12 weeks postpartum using non-pregnancy diagnostic criteria 1, 4, 5, 6
The 75g OGTT is preferred over FBS or A1C for postpartum diagnosis due to its higher sensitivity in detecting glucose intolerance, including prediabetes and diabetes 1
Women with a history of GDM require lifelong screening for diabetes at least every 1-3 years using any glycemic test (A1C, FBS, or 75g OGTT) 1, 2, 5, 6