Adjusted for gestational age (GA) at delivery, GA at ultrasound assessment, Quintero stage, selective fetal growth restriction (sFGR), advanced maternal age (AMA; ≥ 35 years), maternal obesity (body mass index > 35 kg/m2), preterm prelabor rupture of membranes (PPROM); intertwin difference in umbilical artery pulsatility index (DUAPI), umbilical artery (UA) end–diastolic flow (EDF), ductus venosus (DV) flow during atrial contraction and maximum vertical pocket (MVP) in the donor or recipient twin. †Estimated fetal weight (EFW) or birthweight discordance ≥ 25% and EFW < 10th percentile for GA. * DUAPI ≥0.4 was used as reference.