RESUMEN
Umbilical artery catheterisation (UAC) is crucial in the management of clinically sick infants. One of its dreaded complications is aortic thrombus formation which accounts for significant morbidity and mortality. We present the case of a premature infant born at 32 weeks of gestation and with a birth weight of 960 gm, who developed signs of acute lower limb ischaemia following UAC cannulation. Ultrasound Doppler scan confirmed large aortic thrombus involving iliac arteries. Heparin infusion was started with clinical improvement over the next 12 hours and eventual complete resolution of clot size. This case underscores the importance of prompt detection of acute aortic thrombosis and cautions the use of heparin infusion in preterm infants can be lifesaving. Management can be challenging as risk of bleeding from anticoagulation and thrombolytic therapy can be catastrophic in extreme low birthweight premature infants and need to weigh with risk of severe intravascular haemorrhage.