Development and external validation of prognostic markers to predict pump-twin survival in twin reversed…

Cohort studyUltrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology· Aug 2026

Development and external validation of prognostic markers to predict pump-twin survival in twin reversed arterial perfusion sequence.

L-H Wu, Y-Y Yang, H Shen … H-N Xie

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Maternal-Fetal MedicineCohort studyPrognosisQ1IF 4.0

A twin weight ratio below 0.295 is associated with better pump-twin survival.

Development and external validation of prognostic markers to predict pump-twin survival in twin reversed arterial perfusion sequence.

L-H Wu … H-N Xie

Ultrasound in obstetrics & gynecology · Aug 2026 · Q1 in Obstetrics & Gynecology

Purpose

To evaluate the outcome of monochorionic diamniotic (monochorionic diamniotic) pregnancies complicated by twin reversed arterial perfusion (twin reversed arterial perfusion) sequence and to evaluate potential prognostic ultrasound markers as predictors of pump-twin survival.

Methods

This was a retrospective cohort study of monochorionic diamniotic twin pregnancies diagnosed with twin reversed arterial perfusion sequence at two medical centers in China between January 2010 and December 2024.

n = 117 MCDA pregnancies

Results

below this weight ratio of the malformed to healthy twin, survival is better

AUC 0.86 (95% CI 0.73 to 0.99)

CI excludes the null - significant

More results

The overall pump-twin survival rate was 65.8% (77/117).

Three variables (URL and URL/crown-rump length ratio in the first trimester and twin weight ratio in the second trimester) were identified to be independent risk factors influencing pump-twin survival in both the primary and external-validation cohorts.

More results

The twin weight ratio exhibited good calibration, but URL and the URL/crown-rump length ratio exhibited poor calibration.

However, the optimal cut-offs of URL and the URL/crown-rump length ratio showed no statistical difference in the external-validation cohort.

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Conclusion · 1 of 3

After 14 + 0 weeks' gestation, the threshold of twin weight ratio < 0.295 can reliably predict survival of the pump twin in monochorionic diamniotic pregnancies with twin reversed arterial perfusion sequence.

Conclusion · 2 of 3

However, the predictive value of URL and the URL/crown-rump length ratio in the first trimester for pump-twin survival is poor.

Conclusion · 3 of 3

A well-designed prospective multicenter study is warranted to develop a first-trimester multivariable predictive model with enhanced predictive performance. © 2026 International Society of Ultrasound in Obstetrics and Gynecology.

Development and external validation of prognostic markers to predict pump-twin survival in twin reversed arterial perfusion sequence.

Development and external validation of prognostic markers to predict pump-twin survival in twin reversed arterial perfusion sequence.

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