Abdominal circumference ratio for the diagnosis of intertwin birth weight discordance

Teresinha Simoes 1 , Catarina Julio 1 , Alexandra Cordeiro 1 , Alvaro Cohen 1 , Abel Silva 1  and Isaac Blickstein 2
  • 1 Department of Maternal-Fetal Medicine Maternity Dr. Alfredo da Costa, Lisbon, Portugal
  • 2 Department of Obstetrics and Gynecology, Kaplan Medical Center, Rehovot, and the Hadassah-Hebrew University School of Medicine, Jerusalem, Israel


Objectives: We assessed the accuracy of predicting severe twin birth weight discordance (>25%) using the estimated fetal weights (EFW) and abdominal circumference (AC) ratio.

Method: A cohort of twin gestations underwent ultrasound examinations within two weeks from birth. We focused on the accuracy of EFW and on the diagnosis of severe birth weight discordance by the difference in EFWs and the AC ratio.

Results: The 661 eligible twin pairs included 51 (7.7%) severely discordant pairs. The accuracy of an EFW to predict the actual birth weight was quite poor, with an acceptable specificity (96.4%), but low sensitivity (28.6–40.5%), to detect severely discordant pairs, whereas an AC ratio of 1.3 detected these discordant pairs with sensitivity and specificity of 97.3–100% and 99.6–99.7%, respectively.

Conclusion: By comparing EFWs, 59.5–71.4% of discordant pairs >25% are missed, whereas an AC ratio >1.3 would identify almost all cases.

Purchase article
Get instant unlimited access to the article.
Log in
Already have access? Please log in.

Log in with your institution

Journal + Issues

The Journal of Perinatal Medicine is a truly international forum covering the entire field of perinatal medicine. It is an essential news source for all those obstetricians, neonatologists, perinatologists and allied health professionals who wish to keep abreast of progress in perinatal and related research.