Protocol
A research midwife invited potentially eligible women to take part in the trial in the antenatal clinics of the three tertiary participating hospitals. English speaking women at their 36 week visit who were expecting a normal vaginal birth of a single baby were eligible. Signed consent to be randomised in labour was obtained and an identifying stamp affixed to the case notes. Women presenting in uncomplicated labour were eligible to be randomised when they progressed to a visible vertex, full dilatation of the cervix, or 8 cm or more if nulliparous, or 5 cm or more if multiparous