The role of estimated fetal weight discordance in dichorionic twin pregnancies

Evaluation of relative fetal growth in the form of estimated fetal weight discordance (EFWd) is a necessary element of any ultrasound examination in twin pregnancies. It is one of the criteria for the diagnosis of selective fetal growth restriction (sFGR) according to the most established worldwide guidelines. Apart from the effectiveness of this parameter for the diagnosis of sFGR, it may also be used as an independent factor for risk stratification of neonatal and maternal complications. Furthermore, numerous studies have proven the greater prognostic value of EFWd in dichorionic pregnancies, which may result from differences in the pathogenesis of fetal growth abnormalities in mono- and dichorionic pregnancies. Because of the variability of this parameter throughout pregnancy, there is an ongoing discussion regarding replacing or individualizing it with percentile charts. An additional element, complementary to EFWd in assessing the risk of complications in twin pregnancies is the use of this measurement in combination with Doppler assessment, which increases its predictive value. The use of EFWd as one of the factors influencing care and decision-making in dichorionic twin pregnancies seems to be a simple and effective method, however, further research assessing the use and possible applications of this indicator is necessary.