Gestational diabetes screening

USPSTF2021Grade B

Screen asymptomatic pregnant persons (no prior type 1 or 2 diabetes) for gestational diabetes at 24 weeks gestation or later. Options: two-step (50 g 1 hr glucose challenge, then 100 g 3 hr OGTT if positive) or one-step (75 g 2 hr OGTT). Screening before 24 weeks: grade I, evidence insufficient.

ACOG2024

Screen all at 24 to 28 weeks; two-step preferred (50 g 1 hr challenge, then 100 g 3 hr OGTT, Carpenter-Coustan thresholds), one-step 75 g 2 hr OGTT acceptable by clinical judgment. No routine screening before 24 weeks. Screen early for pregestational diabetes if risk factors (prior GDM, BMI 25 or higher, 23 or higher in Asian Americans, plus a risk factor such as A1C 5.7 percent or higher or known glucose intolerance); if early test negative, rescreen at 24 to 28 weeks. 2024 Clinical Practice Update modifies Practice Bulletin 190 (2018).

ADA2026Grade A / B

Before 15 weeks, test those with risk factors for undiagnosed diabetes (B; consider testing all) and screen for abnormal glucose metabolism (A1C 5.9-6.4% or fasting glucose 110-125 mg/dL), which predicts later GDM (B). Screen for GDM at 24-28 weeks if not already diagnosed (A). After GDM: 75-g OGTT at 4-12 weeks postpartum using nonpregnancy criteria (B), then lifelong screening every 1-3 years (B).