The timing of umbilical cord clamping in 38 women with preterm labour was randomly assigned. Ultrasonographic evidence of periventricular/intraventricular haemorrhage (PVH/IVH), assessed blindly, was found in 77% of the group clamped early compared with 35% of those in whom clamping of the cord was delayed for 1 minute. A hypothesis to explain the possible contribution of the haemodynamic events which accompany cord clamping to the development of PVH/IVH is presented.