Gestational Diabetes Screening Guidelines

Current Recommendations

The American College of Obstetricians and Gynecologists, American Diabetes Association, and American College of Physicians recommend that women with BMI ≥30 kg/m² should be screened at their first prenatal visit (12-14 weeks) to detect pre-existing undiagnosed type 2 diabetes 1, 2
Early screening at BMI ≥30 is intended to identify pre-existing diabetes that was undiagnosed before pregnancy, not just gestational diabetes 1
If early screening is negative in these high-risk women, repeat screening at 24-28 weeks is mandatory 1, 3
The American Diabetes Association recommends routine gestational diabetes screening between 24-28 weeks of gestation for all pregnant women using either a one-step or two-step approach 1, 3
The U.S. Preventive Services Task Force gives a B recommendation (moderate net benefit) for screening all asymptomatic pregnant women after 24 weeks of gestation 1

ACOG previously defined low-risk women who could potentially be excluded from screening as those meeting ALL of the following: age <25 years, BMI ≤25 kg/m², no history of abnormal glucose tolerance, no adverse obstetric outcomes, no first-degree relative with diabetes, and not from a high-risk ethnic group 4
This was an exclusion criterion (identifying who might skip screening), not a threshold for requiring screening 4

For BMI ≥30 kg/m²: screen at first prenatal visit (12-14 weeks) with fasting plasma glucose or OGTT, and if negative, repeat screening at 24-28 weeks 1, 2, 3
For BMI 25-29.9 kg/m² with additional risk factors: consider early screening at first prenatal visit, and repeat screening at 24-28 weeks if initial screen is negative 1
For BMI <25 kg/m²: standard screening at 24-28 weeks unless other high-risk factors are present 1

The U.S. Preventive Services Task Force provides a B recommendation (moderate net benefit) for universal screening after 24 weeks to reduce preeclampsia, macrosomia, and shoulder dystocia 5
There is insufficient evidence for screening before 24 weeks in average-risk women, according to the U.S. Preventive Services Task Force 5

Women with BMI >25 kg/m² have over 4 times the risk of developing GDM compared to normal-weight women, with BMI in early pregnancy being a significant risk factor for GDM (OR 4.14) 5