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Poster Session 4

Category: Ultrasound/Imaging

Poster Session 4

(1035) Adding Abdominal Circumference <10th Percentile to Estimated Fetal Weight <10th Percentile for Predicting Neonatal Morbidity

Thursday, February 12, 2026

3:30 PM - 5:00 PM

Submitting Author and Presenting Author(s)

Ashley Shea, MD, MPH

Center for Research in Women’s Health, University of Alabama at Birmingham
Birmingham, Alabama, United States

Coauthor(s)

JO

John Owen, MD, MSPH

Professor
Center for Women’s Reproductive Health Department of Obstetrics and Gynecology University of Alabama at Birmingham
Birmingham, Alabama, United States
Katherine L. Grantz, MD, MSCR

Senior Investigator
Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health
Bethesda, Maryland, United States
Marcia Des Jardin, MD

Maternal Fetal Medicine & Medical Genetics Fellow
Center for Research in Women’s Health, University of Alabama at Birmingham
Birmingham, Alabama, United States
Kevin S. Shrestha, MD, MPH

Fellow
Center for Research in Women’s Health, University of Alabama at Birmingham
Birmingham, Alabama, United States
Ashley N. Battarbee, MD, MSCR

Associate Professor, Maternal-Fetal Medicine
Center for Research in Women’s Health, University of Alabama at Birmingham
Birmingham, Alabama, United States

Objective:
SMFM and ACOG added abdominal circumference (AC) < 10th %ile to estimated fetal weight (EFW) < 10th %ile to diagnose fetal growth restriction (FGR); however, whether this addition improves neonatal morbidity prediction is unknown. Our objective was to determine if using AC < 10th %ile or EFW < 10th %ile (EFW+AC) was associated with improved prediction of composite adverse neonatal outcomes (CANO) and small-for-gestational-age (SGA) at birth, compared to EFW < 10th %ile alone.

Study Design:
We performed a retrospective cohort study of pregnant patients at a tertiary care center who had a scan with complete fetal biometry < 28 days before birth and delivered 1/2022-12/2023. Clinically significant anomalies and multiples were excluded. Both EFW and AC %iles were evaluated by NICHD charts. Outcomes were: 1) CANO (Table) and 2) SGA at birth. Logistic regression modeled the association of each FGR definition with outcomes and receiver operator characteristic area under the curve (AUC) compared predictive abilities.

Results:
Of 3,975 patients included, the mean GA at last ultrasound was 36.0±2.1 wks with delivery at mean GA 37.8±2.1 wks. Overall, 8.3% of patients met criteria for FGR by EFW+AC vs 7.4% by EFW alone (p< 0.0001); 16.5% were SGA and 29.7% had CANO. While both FGR definitions were associated with CANO (EFW+AC: RR 1.83, 95% CI 1.6-2.1; EFW alone: RR 1.85, 95% CI 1.6-2.1; p< 0.0001, Table), neither were good predictors of CANO (EFW+AC: AUC 0.54, 95% CI 0.53-0.55; EFW alone: AUC 0.54, 95% CI 0.53-0.55, p=0.11). Both definitions had acceptable discrimination of SGA (Figure). Sensitivity analyses removing hyperbilirubinemia and hypoglycemia from CANO exhibited similar results (Table and Figure).

Conclusion:
The addition of AC < 10th %ile to EFW < 10th %ile significantly increased the rate of FGR but did not improve the prediction of CANO compared to EFW alone. Given the increased use of prenatal resources to care for patients with FGR and the risk of iatrogenic premature birth, randomized clinical trials are warranted to determine if using the new expanded definition improves perinatal outcomes.