Congenital anomalies of the infrarenal inferior vena cava (IVC) are well described in adult life, however, little information exists on their associations in fetal life. Here, we describe a case of a monochorionic diamniotic (MCDA) twin pregnancy complicated by selective fetal growth restriction (sFGR) with an incidental finding of a double IVC in one child. In fetal life, variants of the infrarenal IVC are strongly associated with heart defects, which might suggest haemodynamic alterations or genetic causes, even more so in our case with MCDA twins complicated by sFGR.