Routine Ultrasound Screening for Large-for-Gestational-Age Fetuses at Term: Balancing Diagnostic Limitations and Intervention Risks

Highlight

• Routine third-trimester ultrasound screening for large-for-gestational-age (LGA) and macrosomic fetuses has limited diagnostic sensitivity (~35%) despite high specificity (~95-97%).
• Screen-positive results significantly increase obstetric interventions including reduced labor attempts and higher intrapartum cesarean delivery rates.
• There is a “labeling effect” where suspicion of fetal largeness drives maternal interventions and adverse maternal outcomes without clear neonatal benefit.
• Findings support reconsidering universal LGA screening at term in favor of individualized, risk-based late pregnancy assessment strategies.

Study Background