INJURY to the anal sphincter during childbirth is more common than was previously realised, particularly with forceps delivery. It is often associated with bowel problems such as incontinence, researchers from St Mark's and St Bartholomew's Hospitals, London, report in the New England Journal of Medicine. They used an ultrasound scanner with a rotating rectal probe to identify anal damage. Of 79 women in the study who had a first vaginal delivery, 35 per cent had anal defects. Women who had forceps deliveries were at greatest risk.