Twin Research and Human Genetics


Blood Flow Changes in Dichorionic Twins With Growth Discordance

Mariola Ropacka-Lesiaka1, Grzegorz Bręborowicza1 and Anna Deraa1 c1

a1 Department of Perinatology and Gynecology, Poznan University of Medical Sciences, Poznan, Poland


Aim: The study evaluated the applicability of Doppler ultrasonography in predicting the course of pregnancy and neonatal outcome in dichorionic pregnancy complicated by growth discordance. Methods: Doppler examination of the umbilical artery (UA) and middle cerebral artery (MCA) was performed in 106 twins. Abnormal values of the UA pulsatility index (PI) were considered to be above the 95th percentile and below 5th percentile for the MCA PI for gestational week. The difference of UA PI ≥0.5 in twin pairs was considered abnormal. Doppler results were compared with selected parameters that characterize the course of pregnancy and fetal outcome. Results: Abnormal UA PI as well as the intertwine PI difference of 0.5 and more correlated significantly with lower gestational age at delivery, intertwine growth discordance of 35% or more, lower birth weight, and abnormal fetal outcome. The abnormal cerebro-umbilical (C/U) ratio correlated statistically with lower birth weight, abnormal fetal outcome, and an increased risk of premature delivery. There were no statistically significant differences in the majority of parameters that characterize the neonatal outcome between the groups with normal and abnormal MCA PI. Conclusion: The intertwine UA PI difference ≥0.5 had the highest predictive value in the assessment of adverse fetal outcome and risk for small for gestational age (SGA). Relatively poor sensitivity was noted with regard to the abnormal values of UA PI and C/U ratio. The worse correlation was found in case of MCA PI.

(Received August 17 2011)

(Accepted May 29 2012)

(Online publication August 10 2012)


  • dichorionic twins;
  • growth discordance


c1 address for correspondence: Anna Dera, Department of Perinatology and Gynecology, Poznan University of Medical Sciences, Polna 33, Poznan 60-535, Poland. E-mail: