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Poster Session 2

Category: Ultrasound/Imaging

Poster Session 2

(569) Clinical Impact of Fetal Weight Estimation Errors on Maternal and Neonatal Outcomes

Wednesday, February 11, 2026

3:30 PM - 5:00 PM

Submitting Author and Presenting Author(s)

Lior Heresco, MD

Meir Medical Center
Kfar Saba, HaMerkaz, Israel

Coauthor(s)

SK

Sharon Kronkop

Ben-Gurion University of the Negev
Beer Sheva, HaDarom, Israel
CB

Chaya Ben Yehuda

Clalit Health Services
Tel Aviv, HaMerkaz, Israel
Hadar Gluska, MD

Meir Medical Center
Kfar Saba, HaMerkaz, Israel
Tal Biron-Shental, MD (she/her/hers)

Chair OBGYN, MFM
Meir Medical Center
Kfar Saba, HaMerkaz, Israel
OW

Omer Weitzner, MD

Meir Medical Center
Kfar Saba, HaMerkaz, Israel

Objective:
Accurate fetal weight estimation (EFW) is essential in obstetric care yet commonly exhibits error margins of 10–15%.Limited data exist regarding the clinical consequences of EFW inaccuracies. This study aimed to assess maternal and neonatal outcomes in relation to EFW error percentage.

Study Design:
This retrospective cohort study included patients with singleton pregnancies delivered between 2014-2023, with an EFW performed within 14 days prior to delivery. EFW error was calculated as the percentage difference between ultrasound-estimated and actual birthweight. Patients were categorized into two groups: < 10% and ≥10% EFW error. Baseline characteristics and outcomes were compared, and adjusted multivariate regression was used to assess the association between error level and risk of cesarean delivery (CD).

Results:
A total of 19,338 patients were included; 14,410 (74.5%) had EFW error < 10%, and 4,820 (25.5%) had error ≥10%. The ≥10% group had higher rates of nulliparity (35% vs. 32%, p< 0.001), delivered slightly earlier (39.4 vs. 39.5 weeks, p=0.001), and had lower maternal height (162.8 vs. 163.4 cm, p=0.007).CD was more frequent in the ≥10% group (19.1% vs. 17.1%, p=0.002), both for labor arrest (3.3% vs. 3.2%, p=0.04) and fetal distress (7.6% vs. 6.2%, p=0.04).No differences were observed in CD type (elective vs. urgent).Neonates in the ≥10% group had lower birthweight (3276 vs. 3381 g, p=0.001), with higher rates of macrosomia ( >4000g: 9.4% vs. 8.1%, p=0.007) and low birthweight (< 2500g: 6.6% vs. 3.3%, p< 0.001). In multivariate analysis, ≥10% error was not associated with an increased risk of CD (OR 0.98; 95% CI 0.86–1.12), whereas an error of ≥20% significantly raised the risk of CD (OR 1.68; 95% CI 1.27–2.22).

Conclusion:
An EFW error of ≥10% was not independently linked to an increased risk of CD, while errors of ≥20% significantly elevated the risk. These findings provide reassurance regarding typical error margins but highlight the importance of caution and repeated expert evaluation in cases at high risk for inaccurate fetal weight assessment.