Vasa praevia is a rare condition in which the foetal blood vessels cross the foetal membranes of the lower segment of the uterus below the presenting part. It has a high foetal mortality due to foetal exsanguination resulting from foetal vessels tearing when the membranes rupture. Prenatal diagnosis can reduce or even prevent foetal mortality, but it requires a high level of suspicion. For this reason, pregnant women with risk factors of vasa praevia should be examined using transvaginal ultrasound in combination with colour Doppler, and if the diagnosis is made, elective delivery by caesarean and aggressive resuscitation of the new born is indicated. Copyright © 2013 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.