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Poster Session 2

Category: Antepartum Fetal Assessment

Poster Session 2

(616) Prognostic Value and Progression of Umbilical Artery Doppler in Dichorionic Twin Pregnancies with Early-Onset FGR

Wednesday, February 11, 2026

3:30 PM - 5:00 PM

Submitting Author and Presenting Author(s)

Noam Pardo, MD, BSc (he/him/his)

MFM Fellow
Sunnybrook Health Sciences Centre
Toronto, Ontario, Canada

Coauthor(s)

JK

John C. Kingdom, MD, MD

Maternal Fetal Medicine Division, Department of Obstetrics and Gynaecology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
Toronto, Ontario, Canada
Liran Hiersch, MD

MFM specialist
Lis Hospital for Women’s Health, Tel Aviv Sourasky Medical Center Gray Faculty of Medicine, Tel Aviv University, Israel
ISRAEL, Tel Aviv, Israel
Nir Melamed, MD

Staff
Sunnybrook Health Sciences Center
Toronto, Ontario, Canada

Objective:
The mechanisms underlying fetal growth restriction (FGR) in twin pregnancies may differ from those in singletons. These differences may affect the relationship between placental insufficiency and umbilical artery (UA) Doppler. In the current study, we aimed to compare the rate of UA Doppler progression and time to delivery between dichorionic twin and singleton pregnancies with severe early-onset FGR.

Study Design:
We conducted a retrospective study of dichorionic twins and singletons with severe early-onset FGR, defined as FGR diagnosed < 32 weeks, accompanied by absent or reversed end-diastolic flow (AREDF) in the UA. UA Doppler changes were classified as elevated UA-PI, intermittent or persistent absent end-diastolic flow (iAEDF or AEDF), and intermittent or persistent reversed end-diastolic flow (iREDF or REDF).

Results:
A total of 46 dichorionic twin pregnancies and 241 singleton pregnancies (701 and 1,835 ultrasound exams, respectively) were analyzed. Twins were characterized by a higher gestational age at diagnosis with AREDF (28.6±3.7 vs. 27.5±3.2 weeks, p=0.032) and at birth (31.2±2.2 vs. 28.6±3.1 weeks, p< 0.001) (Figure 1), and a lower rate of preeclampsia (8.7% vs. 24.1%, p=0.02). Doppler progression was overall slower in twins than in singletons. For example, the mean time (in days) of progression from elevated UA-PI to iAEDF, iREDF, and REDF was 14±16 vs. 7±8 (p=0.025), 21±20 vs. 9±8 (p=0.007), and 25±3 vs. 8±8 (p=0.007), respectively. Twins were also characterized by a longer interval to delivery compared with singletons following elevated UA-PI (median 16 [IQR 6-26] vs. 6 [3-12] days, p< 0.001) and iAEDF (11 [5-17] vs. 4 [2-11] days, p=0.001) (Figure 2).

Conclusion:
In pregnancies complicated by severe early-onset FGR with AREDF, dichorionic pregnancies are characterized by a later onset of AREDF, a slower progression rate of UA Doppler findings, and a longer interval from UA Doppler abnormalities to delivery. This information may be useful for patient counseling and can inform fetal surveillance in these high-risk pregnancies.